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#2117344 - 07/14/13 02:42 AM refinishing nitrocellulose
berninicaco3 Offline
Full Member

Registered: 06/14/13
Posts: 103
Loc: iowa city, ia
I'm refinishing my nitrocellulose piano.
The old finish is crazed.

Just want to verify a detail.

I'm taking real time to sand it, wherever it is actually loose and flaking. And where a flake has come loose, I'll sand the whole area to make sure I don't have a low spot.

But that is ALL I must do, correct?

Where the finish is intact, but crackled, I can respray over it, and the new nitrocellulose will melt into the old?
smoothing it out, restrengthening the old finish, covering over the crackles, restoring some gloss?

I'm more familiar with shellac, but a buddy is teaching me to spray nitro. First time working with it, and first time repairing an old nitro finish. Just wanted to double check this point.

If I don't have to sand the ENTIRE case, to just smooth it out with some new fresh coats-- that would be awesome.
Other areas, like the music desk, that show extreme damage-- I've sanded to bare wood and then restained to match before spraying.


Edited by berninicaco3 (07/14/13 02:43 AM)

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#2117359 - 07/14/13 03:51 AM Re: refinishing nitrocellulose [Re: berninicaco3]
Jim Dunleavy Offline
Full Member

Registered: 02/27/05
Posts: 228
Loc: The Original Washington (UK)
The most critical thing you need to do is make sure all traces of wax furniture polish have been removed.

No other finish will stick over wax polish.

Here's a link to an article on how to remove polish - link .
_________________________
Jim (amateur musician and composer..and piano tinkerer).

Restoration Project Videos

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#2117371 - 07/14/13 04:57 AM Re: refinishing nitrocellulose [Re: berninicaco3]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7426
Loc: France
Where it is cracked it may need to be stripped, in my opinion

a satin finish is easier
_________________________
It is critical that you call your Senators and Representatives and ask them to cosponsor S. 2587 and H.R. 5052. Getting your legislators to cosponsor these bills


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#2117680 - 07/14/13 08:10 PM Re: refinishing nitrocellulose [Re: berninicaco3]
Nash. Piano Rescue Offline
Full Member

Registered: 12/08/09
Posts: 384
Loc: East Nashville,TN Scottsville...
How did you establish that the old finish was Nitro-celluose? If you take a flake of finish and put it in a jar with denatured alcohol and it dissolves it is Shellac not Lacquer.

Nitro-Cellulose is reduced at a ratio of 1 to 1 with reducer if you are spraying it. Make sure you use the right type and you cannot use reducer for acrylic enamel which is a common error.

Find Mohawk paints website and take a look at the catalog. They are based in North Carolina. They carry a wide variety of piano related finishing products.
_________________________
J. Christie
Nashville Piano Rescue
www.NashvillePianoRescue.com
East Nashville
Bowling Green, KY
Scottsville KY.
Chamber of Commerce
Member/Sponsor

Putting inspiration in the hands of area musicians
Through restoration/renovation

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#2117800 - 07/14/13 10:50 PM Re: refinishing nitrocellulose [Re: Nash. Piano Rescue]
phacke Online   content

Gold Supporter until November 11 2014


Registered: 10/18/12
Posts: 492
Loc: CO, USA
Originally Posted By: Nash. Piano Rescue
...

Nitro-Cellulose is reduced at a ratio of 1 to 1 with reducer if you are spraying it. Make sure you use the right type and you cannot use reducer for acrylic enamel which is a common error.

Find Mohawk paints website and take a look at the catalog. They are based in North Carolina. They carry a wide variety of piano related finishing products.


M. J.Christie,

Can we suppose then you are not talking about the Mohawk 'Piano Lacquer' product, which does not particularly recommend reducing, or...?

http://www.mohawk-finishing.com/mhk_cds/product_pds/m610-130x%20piano%20lacquer.pdf

Which of their lacquer products do you like?

Best wishes -
_________________________
phacke

Steinway YM (1933)
...Working on:
G. F. Händel: Suite in G minor (HWV 452)
J. S. Bach, Sonata No. 1 in B minor (BWV 1014) duet with violin

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#2117957 - 07/15/13 10:42 AM Re: refinishing nitrocellulose [Re: berninicaco3]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7426
Loc: France
products to clean silicones are availeable.

sanding is said to be enough, but there is always a risk (craters)

cracked lacquer is stripped, then the whole finish is done again, cracks does not close when sprayed.
_________________________
It is critical that you call your Senators and Representatives and ask them to cosponsor S. 2587 and H.R. 5052. Getting your legislators to cosponsor these bills


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#2117990 - 07/15/13 12:05 PM Re: refinishing nitrocellulose [Re: berninicaco3]
Nash. Piano Rescue Offline
Full Member

Registered: 12/08/09
Posts: 384
Loc: East Nashville,TN Scottsville...
I actually found Mohawk products by accident when I joined professional refinishers group. I can understand not reducing the gloss lacquer because you will lose sheen without adding hardener but I use two products of theirs mainly but I am curious about their gloss black and may try that out too.

The high build clear piano lacquer is awesome. The type of grain filling I do is old school and will wear a person out. It requires rubbing the surface of the wood with a filler caked burlap bag, after brushing, squee-gee- ing ( sherwin williams oil based Sherwood) until it is basically glass smooth and sometimes there will be a tiny spot missed. The clear Mohawk stuff takes care of that within 2 coats.

As far as the black goes I use the Satin Black colored Lacquer. I will get you a part number if you can't find it. It's reduced 1-1 and the air supply needs to be cool which is one of the secrets of using nitro-cellulose. If you don't have air you can get a tank of dry nitrogen and regulate that. Electric HVLP equipment will not work as the air coming from the hose is too hot unless you can run it through some bags of ice.

I bought 4 gallons of Mohawk products and then they called me to get me dealers rates which will save you like 12 dollars a gallon. They do sell 5 gallon cans but the hazmat shipping charge makes it cheaper to buy 1 gallon cans.
_________________________
J. Christie
Nashville Piano Rescue
www.NashvillePianoRescue.com
East Nashville
Bowling Green, KY
Scottsville KY.
Chamber of Commerce
Member/Sponsor

Putting inspiration in the hands of area musicians
Through restoration/renovation

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#2118004 - 07/15/13 12:39 PM Re: refinishing nitrocellulose [Re: berninicaco3]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7426
Loc: France
Good top to stay away of warm air or too warm room with nitro. The product needs some time to flow on the part, too hot weather gives you a not so nice orange skin defect.
The products I use are cut with thinner. If not they are not nitro but polyurethane.

I heard that new types of nitro lacquer are now used with very little volatile solvents, but they need a cooking.
_________________________
It is critical that you call your Senators and Representatives and ask them to cosponsor S. 2587 and H.R. 5052. Getting your legislators to cosponsor these bills


Top
#2118006 - 07/15/13 12:46 PM Re: refinishing nitrocellulose [Re: berninicaco3]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7426
Loc: France
Originally Posted By: berninicaco3
I'm refinishing my nitrocellulose piano.
The old finish is crazed.

Just want to verify a detail.

I'm taking real time to sand it, wherever it is actually loose and flaking. And where a flake has come loose, I'll sand the whole area to make sure I don't have a low spot.

But that is ALL I must do, correct?

Where the finish is intact, but crackled, I can respray over it, and the new nitrocellulose will melt into the old?
smoothing it out, restrengthening the old finish, covering over the crackles, restoring some gloss?


I'm more familiar with shellac, but a buddy is teaching me to spray nitro. First time working with it, and first time repairing an old nitro finish. Just wanted to double check this point.

If I don't have to sand the ENTIRE case, to just smooth it out with some new fresh coats-- that would be awesome.
Other areas, like the music desk, that show extreme damage-- I've sanded to bare wood and then restained to match before spraying.


That may be all if your base coat is OK, but usually a hard base is sprayed to lock the grain, seal the wood, level, then sanded lightly, then the finish is used.

Undercoat can be polyurethane, that build up more than nitro
_________________________
It is critical that you call your Senators and Representatives and ask them to cosponsor S. 2587 and H.R. 5052. Getting your legislators to cosponsor these bills


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#2118013 - 07/15/13 12:56 PM Re: refinishing nitrocellulose [Re: berninicaco3]
Gene Nelson Offline
1000 Post Club Member

Registered: 09/10/04
Posts: 1471
Loc: Old Hangtown California
An amalgamator will help flatten the checking.
_________________________
RPT
PTG Member

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#2118058 - 07/15/13 02:32 PM Re: refinishing nitrocellulose [Re: berninicaco3]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7426
Loc: France
"An amalgamator will help flatten the checking."

Hi Gene is it the English name ? we use a fluid called "Egalisateur" (' Evener' , if I translate literally )

On Nitro high gloss lacquer or on Nitro lacquer that can be sprayed, then rubbed as French polish.
The product is some sort of solvent plus thinner and allow the lacquer to moisten, get smoother, eventually tense when the product dries. helps with blemishes, white clouds, may allow any captured moisture to go away on a recent finish)

Indeed it may be worth a try, (with a rubber, or spraying the product, it may be sold in spray cans or in bottles) but usually when the lacquer is cracked, any work will be at the surface, then the cracks will come back soon later.

Very often also the undercoat is not NItro, but Polyurethane. I also have find polyester as undercoat, and shellac as finish (in the end not pure shellac, but a mix of shellac and cellulose, that was sprayed then rubbed by hand on the polyester coat - German pianos 60's era)

It is important to test with alcohol, acetone, nitro thinner, to understand what is (what are) the original products used.

On polyurethane or polyester you may use any kind of lacquer, PU thinner can thin/cut NItro lacquer, also.

polyester will make a white scratch (and can be cracked)


Edited by Olek (07/15/13 02:49 PM)
_________________________
It is critical that you call your Senators and Representatives and ask them to cosponsor S. 2587 and H.R. 5052. Getting your legislators to cosponsor these bills


Top
#2118061 - 07/15/13 02:48 PM Re: refinishing nitrocellulose [Re: Gene Nelson]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7426
Loc: France
Originally Posted By: Gene Nelson
An amalgamator will help flatten the checking.


excuse me but what is "checking" ?


Edited by Olek (07/15/13 02:48 PM)
_________________________
It is critical that you call your Senators and Representatives and ask them to cosponsor S. 2587 and H.R. 5052. Getting your legislators to cosponsor these bills


Top
#2118195 - 07/15/13 08:19 PM Re: refinishing nitrocellulose [Re: berninicaco3]
Minnesota Marty Offline

Platinum Supporter until October 5 2014


Registered: 05/15/12
Posts: 7239
Loc: Rochester MN
Keep in mind that the piano is a 1936 5'6" Kimball in a mahogany finish. None of the 'Polys' would have been used with a finish from that era. Since it shows signs of checking, it would indicate a lacquer finish, as opposed to shellac or varnish. There is no suitable way to use a solvent to 'soften or re-wet' a finish from this era to erase the damage. Spot refinishing can be attempted, but they are visibly noticeable (obvious) unless done by a very experienced craftsman.

The best results are obtained by stripping the entire instrument and then refinish with the choice of any of the modern materials.
_________________________
Marty in Minnesota

It's much easier to bash a Steinway than it is to play one.

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#2118294 - 07/15/13 11:41 PM Re: refinishing nitrocellulose [Re: Olek]
phacke Online   content

Gold Supporter until November 11 2014


Registered: 10/18/12
Posts: 492
Loc: CO, USA
Originally Posted By: Olek
Originally Posted By: Gene Nelson
An amalgamator will help flatten the checking.


excuse me but what is "checking" ?


Cracking at the surface. Web search 'checking lacquer' brings up some images.

Best wishes-
_________________________
phacke

Steinway YM (1933)
...Working on:
G. F. Händel: Suite in G minor (HWV 452)
J. S. Bach, Sonata No. 1 in B minor (BWV 1014) duet with violin

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#2118303 - 07/16/13 12:08 AM Re: refinishing nitrocellulose [Re: Olek]
phacke Online   content

Gold Supporter until November 11 2014


Registered: 10/18/12
Posts: 492
Loc: CO, USA
Originally Posted By: Olek


On polyurethane or polyester you may use any kind of lacquer, PU thinner can thin/cut NItro lacquer, also.

polyester will make a white scratch (and can be cracked)


Hello again Mr. Oleg,

And, how do you repair such white scratch?

May I use this forum as a confessional?

When I was much younger, I enjoyed opening the lid of my aunt's brand new Schimmel grand piano to play it in all its grandeur (beautiful walnut, chestnut, or cherry, I don't know). This is European piano with the polyester finish, as you know. She used to keep a ceramic-base table lamp on a cloth on the piano top. So in removing the lamp to open the lid, one day, I put a terrible gouge. Yes, I can attest that there is a white scratch that results. Some polish on hand dulled the white, but obviously did't go far to fix it. I never had the courage to tell her, I put the cloth and the lamp back. Some years later I got married and I told my wife the story of the scratch. Then, my wife met my aunt and discussed the story as if my aunt already knew that I had done this damage (but at the time she didn't). Many years had passed however.

So how do you repair such white scratch?
(I am also curious if this is a professional service you provide?)

From this experience, and also with my parent's upright, I am of the opinion that lamps of any kind are one of the most dangerous things for the piano.

Best wishes -


Edited by phacke (07/16/13 12:09 AM)
_________________________
phacke

Steinway YM (1933)
...Working on:
G. F. Händel: Suite in G minor (HWV 452)
J. S. Bach, Sonata No. 1 in B minor (BWV 1014) duet with violin

Top
#2118308 - 07/16/13 12:20 AM Re: refinishing nitrocellulose [Re: Nash. Piano Rescue]
phacke Online   content

Gold Supporter until November 11 2014


Registered: 10/18/12
Posts: 492
Loc: CO, USA
Hello Mr. JChristie,

Thank you for your comments. I have a follow-up question and a few things I can add.

>>"The high build clear piano lacquer is awesome. "
Is this a lacquer that you reduce 1:1 when you use?

>>"The type of grain filling I do is old school and will wear a person out. It requires rubbing the surface of the wood with a filler caked burlap bag, after brushing, squee-gee- ing ( sherwin williams oil based Sherwood) until it is basically glass smooth"

I though the above was the New School. The old school (my impression, at least) being that you apply a coat of lacquer that pops the grain, you then sand the peaks of the swelled grains, and repeat a few times till totally smooth.

>>"Electric HVLP equipment will not work as the air coming from the hose is too hot unless you can run it through some bags of ice."

I have read that, as long as you are not running it continuously, a long hose can help. Anyway, what is the symptom in the applied lacquer if the air into the gun is too hot?

Thanks again -

Originally Posted By: Nash. Piano Rescue
I actually found Mohawk products by accident when I joined professional refinishers group. I can understand not reducing the gloss lacquer because you will lose sheen without adding hardener but I use two products of theirs mainly but I am curious about their gloss black and may try that out too.

The high build clear piano lacquer is awesome. The type of grain filling I do is old school and will wear a person out. It requires rubbing the surface of the wood with a filler caked burlap bag, after brushing, squee-gee- ing ( sherwin williams oil based Sherwood) until it is basically glass smooth and sometimes there will be a tiny spot missed. The clear Mohawk stuff takes care of that within 2 coats.

As far as the black goes I use the Satin Black colored Lacquer. I will get you a part number if you can't find it. It's reduced 1-1 and the air supply needs to be cool which is one of the secrets of using nitro-cellulose. If you don't have air you can get a tank of dry nitrogen and regulate that. Electric HVLP equipment will not work as the air coming from the hose is too hot unless you can run it through some bags of ice.

I bought 4 gallons of Mohawk products and then they called me to get me dealers rates which will save you like 12 dollars a gallon. They do sell 5 gallon cans but the hazmat shipping charge makes it cheaper to buy 1 gallon cans.
_________________________
phacke

Steinway YM (1933)
...Working on:
G. F. Händel: Suite in G minor (HWV 452)
J. S. Bach, Sonata No. 1 in B minor (BWV 1014) duet with violin

Top
#2118314 - 07/16/13 12:39 AM Re: refinishing nitrocellulose [Re: berninicaco3]
phacke Online   content

Gold Supporter until November 11 2014


Registered: 10/18/12
Posts: 492
Loc: CO, USA
Originally Posted By: berninicaco3
I'm refinishing my nitrocellulose piano.

Where the finish is intact, but crackled, I can respray over it, and the new nitrocellulose will melt into the old?
smoothing it out, restrengthening the old finish, covering over the crackles, restoring some gloss?


Hello, berninicaco3 -

I feel like I have hijacked your thread. I have an amateur opinion on the matter.

To do a good job you have to do what Marty wrote, but of course you can spray new stuff on to old stuff (I see furniture fixers do this all the time) unless your new stuff has solvents that eat away at the old stuff. I think you have to test in a small area to see if the old and new materials have satisfactory compatibility if you want to go that route.

Best wishes -
_________________________
phacke

Steinway YM (1933)
...Working on:
G. F. Händel: Suite in G minor (HWV 452)
J. S. Bach, Sonata No. 1 in B minor (BWV 1014) duet with violin

Top
#2118329 - 07/16/13 01:29 AM Re: refinishing nitrocellulose [Re: berninicaco3]
Gene Nelson Offline
1000 Post Club Member

Registered: 09/10/04
Posts: 1471
Loc: Old Hangtown California
Egalisateur sounds like it does about the same job as amalgamator.
Not a cure but it helps.
I use a brush to work it and help persuade the damage to semi liquefy and spread/flatten.
More finish can be added to fill.
Checking is as previously mentioned.
The finish shrinks and cracks or checks develope.

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#2118341 - 07/16/13 01:40 AM Re: refinishing nitrocellulose [Re: berninicaco3]
Gene Nelson Offline
1000 Post Club Member

Registered: 09/10/04
Posts: 1471
Loc: Old Hangtown California
Egalisateur
Interesting word - derived from egalitarian - I suppose it fits the finish better than people.
_________________________
RPT
PTG Member

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#2118363 - 07/16/13 02:08 AM Re: refinishing nitrocellulose [Re: phacke]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7426
Loc: France
Originally Posted By: phacke
Originally Posted By: Olek


On polyurethane or polyester you may use any kind of lacquer, PU thinner can thin/cut NItro lacquer, also.

polyester will make a white scratch (and can be cracked)


Hello again Mr. Oleg,

And, how do you repair such white scratch?

May I use this forum as a confessional?

When I was much younger, I enjoyed opening the lid of my aunt's brand new Schimmel grand piano to play it in all its grandeur (beautiful walnut, chestnut, or cherry, I don't know). This is European piano with the polyester finish, as you know. She used to keep a ceramic-base table lamp on a cloth on the piano top. So in removing the lamp to open the lid, one day, I put a terrible gouge. Yes, I can attest that there is a white scratch that results. Some polish on hand dulled the white, but obviously did't go far to fix it. I never had the courage to tell her, I put the cloth and the lamp back. Some years later I got married and I told my wife the story of the scratch. Then, my wife met my aunt and discussed the story as if my aunt already knew that I had done this damage (but at the time she didn't). Many years had passed however.

So how do you repair such white scratch?
(I am also curious if this is a professional service you provide?)

From this experience, and also with my parent's upright, I am of the opinion that lamps of any kind are one of the most dangerous things for the piano.

Best wishes -


Hello, yes I sometime repair, polyester damage, small ones, white cracks can be hidden with car products (black wax) or black copal, or polyester but it is very difficult, more easy to repair chips than long streaks.

Products for cars can help masking the damage in frontal viewing, it may still be apparent with lateral light or view. A good cheap solution, coral varnish (hard) is another. French polish if well applied gives a good aspect for 20 years (if applied on a crazed poly or finish) then cracks show up again.


Edited by Olek (07/16/13 06:46 AM)
_________________________
It is critical that you call your Senators and Representatives and ask them to cosponsor S. 2587 and H.R. 5052. Getting your legislators to cosponsor these bills


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#2118401 - 07/16/13 05:53 AM Re: refinishing nitrocellulose [Re: berninicaco3]
Jon Page Offline
Full Member

Registered: 03/13/09
Posts: 258
Loc: Harwich Port, Cape Cod, Massac...
You are headed for a disaster. You need to strip the old finish completely. Otherwise, it will lift or craze even more when you apply a new lacquer finish. If it doesn't, or if you use a water based finish to avoid a retraction, eventually the crazing will bleed thru after a few years. There's no quick or cheap workaround to a good finish.
_________________________
Regards,

Jon Page
Piano technician/tuner
Harwich Port, Cape Cod, Massachusetts, USA
http://www.pianocapecod.com

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#2118418 - 07/16/13 07:11 AM Re: refinishing nitrocellulose [Re: Gene Nelson]
Jean Claude Offline
Full Member

Registered: 09/18/11
Posts: 357
Loc: France
Originally Posted By: Gene Nelson
Egalisateur
Interesting word - derived from egalitarian - I suppose it fits the finish better than people.


Egalisateur is from the French égal meaning equal hence 'equaliser' (Lat. aequalis)


Edited by Jean Claude (07/16/13 07:15 AM)

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#2118474 - 07/16/13 10:18 AM Re: refinishing nitrocellulose [Re: berninicaco3]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7426
Loc: France
Thankiou!

The product is used to work the surface, so defects or traces are leveled.

Probably it could be simply sprayed or brushed heavily, but it is better to work with it than yo leave the work to the product, seem to me.
_________________________
It is critical that you call your Senators and Representatives and ask them to cosponsor S. 2587 and H.R. 5052. Getting your legislators to cosponsor these bills


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#2119384 - 07/18/13 12:47 AM Re: refinishing nitrocellulose [Re: Olek]
Steven Bolstridge Offline
Full Member

Registered: 06/13/05
Posts: 197
Loc: Fitzgerald ,GA
It needs to be stripped and finished properly. Sanding can make the final finish uneven and blotchy. Why do all this work on a hunch or a gamble?
_________________________
piano tuner/technician

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#2119504 - 07/18/13 08:17 AM Re: refinishing nitrocellulose [Re: Steven Bolstridge]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7426
Loc: France
Originally Posted By: Steven Bolstridge
It needs to be stripped and finished properly. Sanding can make the final finish uneven and blotchy. Why do all this work on a hunch or a gamble?


It can be done if the undercoat is not cracked or whitened, and if you spray satin or matt finish.

If stripped, the grain have to be closed which means a lot of product and coats.

Cellulose finishes once the undercoat is done can mean as much as 8 coats, as the thickness of the lacquer , for one spraying is really small. But coats can be done at 30 minutes interval, in quiet temperature (too hot and the spray dry before attaining the case)

Better use Polyurethane if the complete lacquering have to be done. this is really toxic and smell strong.

Or apply a French polish, but one need to know how to do, what to use, etc (dismount whatever is necessary).

The low pressure guns mean the spraying is done near the surface. AT last it apply 65% of the product (standard spray guns 30%, the rest goes in the air)

here the top have been fine sanded, spots of colour on water stains and 3 lacquer passes.

_________________________
It is critical that you call your Senators and Representatives and ask them to cosponsor S. 2587 and H.R. 5052. Getting your legislators to cosponsor these bills


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#2119526 - 07/18/13 09:20 AM Re: refinishing nitrocellulose [Re: berninicaco3]
Nash. Piano Rescue Offline
Full Member

Registered: 12/08/09
Posts: 384
Loc: East Nashville,TN Scottsville...
Just an added note on sanding for novices. Avoid the draw to rotary sanders. I use a lot of air equipment mainly because it is more efficient but stay with the inline straight type sanders over anything that spins to avoid sanding swirls.

In the wood finishing world they say give all your rotary sanders to the competitors you don't like Ha !
_________________________
J. Christie
Nashville Piano Rescue
www.NashvillePianoRescue.com
East Nashville
Bowling Green, KY
Scottsville KY.
Chamber of Commerce
Member/Sponsor

Putting inspiration in the hands of area musicians
Through restoration/renovation

Top
#2119828 - 07/18/13 08:18 PM Re: refinishing nitrocellulose [Re: Minnesota Marty]
OperaTenor Offline
2000 Post Club Member

Registered: 04/13/06
Posts: 2380
Loc: Sandy Eggo, California
Originally Posted By: Minnesota Marty
Keep in mind that the piano is a 1936 5'6" Kimball in a mahogany finish. None of the 'Polys' would have been used with a finish from that era. Since it shows signs of checking, it would indicate a lacquer finish, as opposed to shellac or varnish. There is no suitable way to use a solvent to 'soften or re-wet' a finish from this era to erase the damage. Spot refinishing can be attempted, but they are visibly noticeable (obvious) unless done by a very experienced craftsman.

The best results are obtained by stripping the entire instrument and then refinish with the choice of any of the modern materials.


Shellac crackles more than any other type of finish. I'm currently refinishing my 1925 Chickering Ampico A, which had a horribly crackled shellac finish. So far, I've stripped the case and the lid; the wood underneath is gorgeous. And, my 1921 Hamilton Manualo has the same ugly old finish.
_________________________
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#2119849 - 07/18/13 09:06 PM Re: refinishing nitrocellulose [Re: berninicaco3]
Nash. Piano Rescue Offline
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Registered: 12/08/09
Posts: 384
Loc: East Nashville,TN Scottsville...
Shellac gets a bad rap sometimes but they still use it to seal M&Ms it is non toxic. You can use it as a sealer against Silicone contamination over sanded primer if doing solid colors.

If you are really good and like to curse a lot there is always Vinyl Sealer which is what most cabinet shops use to seal out impurities. I think you could spray that stuff over a leaking quart of oil and get a flawless paint job on it but the issue with Vinyl sealer is if the batch is old it can crack after it dries under your finish.

I still do it the old way. Dye the wood with transtint mixed with water, sand, grain fill, stain, then 3 - 4 coats of sanding sealer sprayed on, block sand 320 - 400 then shoot the clear and rub it out if it needs it. With solid colors it just depends on how wild the paint job gets as to how we build it out.
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#2119898 - 07/18/13 10:47 PM Re: refinishing nitrocellulose [Re: berninicaco3]
OperaTenor Offline
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Registered: 04/13/06
Posts: 2380
Loc: Sandy Eggo, California
I happen to really like shellac. I'm going to use it to refinish my Chickering.

A trivia question: Without googling, does anyone here know where shellac comes from, and was it is?





Edited by OperaTenor (07/18/13 10:47 PM)
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#2119903 - 07/18/13 10:54 PM Re: refinishing nitrocellulose [Re: berninicaco3]
Minnesota Marty Offline

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Registered: 05/15/12
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Secretions from the Lac bug.
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#2119925 - 07/18/13 11:34 PM Re: refinishing nitrocellulose [Re: Minnesota Marty]
OperaTenor Offline
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Registered: 04/13/06
Posts: 2380
Loc: Sandy Eggo, California
Originally Posted By: Minnesota Marty
Secretions from the Lac bug.


You Sir win three internets for a correct answer!

I think of it as lac beetle spit...
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#2119997 - 07/19/13 02:59 AM Re: refinishing nitrocellulose [Re: OperaTenor]
Olek Online   content
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Registered: 03/14/08
Posts: 7426
Loc: France
Originally Posted By: OperaTenor
Originally Posted By: Minnesota Marty
Keep in mind that the piano is a 1936 5'6" Kimball in a mahogany finish. None of the 'Polys' would have been used with a finish from that era. Since it shows signs of checking, it would indicate a lacquer finish, as opposed to shellac or varnish. There is no suitable way to use a solvent to 'soften or re-wet' a finish from this era to erase the damage. Spot refinishing can be attempted, but they are visibly noticeable (obvious) unless done by a very experienced craftsman.

The best results are obtained by stripping the entire instrument and then refinish with the choice of any of the modern materials.


Shellac crackles more than any other type of finish. I'm currently refinishing my 1925 Chickering Ampico A, which had a horribly crackled shellac finish. So far, I've stripped the case and the lid; the wood underneath is gorgeous. And, my 1921 Hamilton Manualo has the same ugly old finish.



It doe not really more because it is more supple than cellulose (cellulose have bad reputation about cracking and whitening) but was often used on sealers that can crack.,

Shellac finish is "easy" to repair, but fragile to solvents.



Edited by Olek (07/19/13 03:23 AM)
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#2120001 - 07/19/13 03:02 AM Re: refinishing nitrocellulose [Re: Nash. Piano Rescue]
Olek Online   content
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Registered: 03/14/08
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Loc: France
Originally Posted By: Nash. Piano Rescue
Shellac gets a bad rap sometimes but they still use it to seal M&Ms it is non toxic. You can use it as a sealer against Silicone contamination over sanded primer if doing solid colors.

If you are really good and like to curse a lot there is always Vinyl Sealer which is what most cabinet shops use to seal out impurities. I think you could spray that stuff over a leaking quart of oil and get a flawless paint job on it but the issue with Vinyl sealer is if the batch is old it can crack after it dries under your finish.

I still do it the old way. Dye the wood with transtint mixed with water, sand, grain fill, stain, then 3 - 4 coats of sanding sealer sprayed on, block sand 320 - 400 then shoot the clear and rub it out if it needs it. With solid colors it just depends on how wild the paint job gets as to how we build it out.


Hello I am surprised of that use as sealer. I heard also of that using spray cans).

The sprayeable shellac based products may content some cellulose too, I believe.

I guess that if I spray a cellulose finish on a shellac base it will melt it and I take the risk of burning the "primer".

Does it work ?

Regards
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#2120120 - 07/19/13 11:06 AM Re: refinishing nitrocellulose [Re: berninicaco3]
Minnesota Marty Offline

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Registered: 05/15/12
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Jim,

I have been giving a lot of thought to your statement that shellac is the most prone to 'checking' or 'crazing,' and I put that back in the context of 1936. From the turn of the twentieth century, shellac was rarely used in furniture building, it was most common for wall paneling or floors, though varnish was considered a better option for those uses. Shellac is a very soft finish and scratches easily. Checking is not usually considered one of its characteristics.

By 1936, Kimball would most certainly be using sprayed nitrocellulose lacquer, the product developed by Dupont, rather than the traditional formulation of lacquer as used in the nineteenth century. Shellac, as used in a traditional "French Polish" was very rare in the US and not used by piano builders or cabinet/furniture makers.

On the piano that you are working on, is the solvent for the finish alcohol? Often small cracks can be repaired as a surface treatment using alcohol and very fine steel wool. These finishes will rarely develop the large scale 'alligator' checking as will a lacquer finish from spending many years in direct sunlight.

So, I've been curious about your experience and would very much like to hear your thoughts.

Cheers,
_________________________
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#2120121 - 07/19/13 11:07 AM Re: refinishing nitrocellulose [Re: berninicaco3]
Gene Nelson Offline
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Registered: 09/10/04
Posts: 1471
Loc: Old Hangtown California
I have used shellac as a sealer- once to seal over linseed oil that was used for color coat.
Then seedlac followed by water based lacquer.

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#2120196 - 07/19/13 02:54 PM Re: refinishing nitrocellulose [Re: berninicaco3]
Silverwood Pianos Offline
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Registered: 03/10/08
Posts: 4187
Loc: Vancouver B. C. Canada

Nitro cellulose finishes were used on production furniture from 1900 and by 1930 was in common use.

Duco the paint product developed by Dupont in 1923 was an automotive paint first used on the GM Oakland line of autos.
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#2120201 - 07/19/13 03:04 PM Re: refinishing nitrocellulose [Re: berninicaco3]
BDB Offline
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I have had tours of the old Oakland assembly plant, both in its former life making automobiles and its current use, the central maintenance facility for the local bus transit agency.
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#2120210 - 07/19/13 03:14 PM Re: refinishing nitrocellulose [Re: berninicaco3]
berninicaco3 Offline
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Registered: 06/14/13
Posts: 103
Loc: iowa city, ia
I always wondered about hardware store shellac.
The real stuff of course is in 1# bags, that I seem to remember being a great deal cheaper than I recently saw...

But when you get zinsser shellac by the gallon-- is it shellac shellac?

Terminologies get confused. Lacquer and varnish get used interchangeably. There are more chemistries out there now, than just lac bug wax, damar resin, and nitro.

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#2120211 - 07/19/13 03:15 PM Re: refinishing nitrocellulose [Re: berninicaco3]
berninicaco3 Offline
Full Member

Registered: 06/14/13
Posts: 103
Loc: iowa city, ia
BTW, as an update:
repairing the old finish seems to be working out nicely.
still getting a hang of spraying smoothly.

But the first results are taking, no fisheyes, no delamination. If it crackles in several years... I'll be OK. I kinda liked the crackle anyway.
What I didn't like was the damage and the flaking.

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#2120218 - 07/19/13 03:41 PM Re: refinishing nitrocellulose [Re: berninicaco3]
Silverwood Pianos Offline
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Registered: 03/10/08
Posts: 4187
Loc: Vancouver B. C. Canada
There is no interest in my experience or postings here so this was not posted earlier;

For what it’s worth;

Wiped down with methyl hydrate would have cleaned off all the oils, dirt, fingerprints, etc. and left the old surface absolutely clean.

When the methyl evaporated it would have left white streaks which is the old finish grabbing moisture out of the air as it evaporated. This reveals the old surface is softened by the methyl and can be re-started.

When a new coat is sprayed over top this releases the trapped water and the blush disappears. The first new coat would have revealed all of the divots and bumps which are then filled with clear or sanded down. Then the second coat would get the skating rink.

Only good for 5 years. If the old finish was flaking off maybe trouble coming before that time. Flaking reveals lack of adhesion. Makes for an unstable base coat.

Mixing nitro 1 to 1? That is 50% reduction and have never heard of that.

Hello orange peel……

Most lacquer products can be used straight out of the can or 10% reduction. 30% if you want to use as sealer coat.
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#2120224 - 07/19/13 03:59 PM Re: refinishing nitrocellulose [Re: Minnesota Marty]
OperaTenor Offline
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Registered: 04/13/06
Posts: 2380
Loc: Sandy Eggo, California
Originally Posted By: Minnesota Marty
Jim,

I have been giving a lot of thought to your statement that shellac is the most prone to 'checking' or 'crazing,' and I put that back in the context of 1936. From the turn of the twentieth century, shellac was rarely used in furniture building, it was most common for wall paneling or floors, though varnish was considered a better option for those uses. Shellac is a very soft finish and scratches easily. Checking is not usually considered one of its characteristics.

By 1936, Kimball would most certainly be using sprayed nitrocellulose lacquer, the product developed by Dupont, rather than the traditional formulation of lacquer as used in the nineteenth century. Shellac, as used in a traditional "French Polish" was very rare in the US and not used by piano builders or cabinet/furniture makers.

On the piano that you are working on, is the solvent for the finish alcohol? Often small cracks can be repaired as a surface treatment using alcohol and very fine steel wool. These finishes will rarely develop the large scale 'alligator' checking as will a lacquer finish from spending many years in direct sunlight.

So, I've been curious about your experience and would very much like to hear your thoughts.

Cheers,


Yes, I'm using denatured alcohol to strip it. If you go to my No Piano Left Behind Facebook page (and like it, of course laugh ), I have photos of the work I've been oh so slowly doing on it.

I chose to strip is rather than just smooth it out because the finish had darkened, and it was difficult to discern the wood grain anymore. I am going to refinish it with shellac as well; I really like working with it.


Here's a sample, showing the comparison between the existing finish and how it looks stripped/refinished:



Edited by OperaTenor (07/19/13 04:10 PM)
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#2120253 - 07/19/13 05:14 PM Re: refinishing nitrocellulose [Re: berninicaco3]
Jon Page Offline
Full Member

Registered: 03/13/09
Posts: 258
Loc: Harwich Port, Cape Cod, Massac...
So, I take it, you're not using paste wood filler to close the pores and going with an open-pore finish. You'll want to remove that shellac stripe before doing the whole lid, it may show otherwise.
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#2120289 - 07/19/13 06:55 PM Re: refinishing nitrocellulose [Re: Silverwood Pianos]
Olek Online   content
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Registered: 03/14/08
Posts: 7426
Loc: France
Originally Posted By: Silverwood Pianos
There is no interest in my experience or postings here so this was not posted earlier;

For what it’s worth;

Wiped down with methyl hydrate would have cleaned off all the oils, dirt, fingerprints, etc. and left the old surface absolutely clean.

When the methyl evaporated it would have left white streaks which is the old finish grabbing moisture out of the air as it evaporated. This reveals the old surface is softened by the methyl and can be re-started.

When a new coat is sprayed over top this releases the trapped water and the blush disappears. The first new coat would have revealed all of the divots and bumps which are then filled with clear or sanded down. Then the second coat would get the skating rink.

Only good for 5 years. If the old finish was flaking off maybe trouble coming before that time. Flaking reveals lack of adhesion. Makes for an unstable base coat.

Mixing nitro 1 to 1? That is 50% reduction and have never heard of that.

Hello orange peel……

Most lacquer products can be used straight out of the can or 10% reduction. 30% if you want to use as sealer coat.


Hello, that is interesting, but methyl hydrate is not availeable probably today in Europe, forbid, as many solvents.


Due to the spraying equipment (HVLP on standard compressor) and hot weather, I had to cut my Nitro up to 30% (20-30%)on the behalf of the provider .

When you talk of "pre cat" laquer, that ring to me as polyurethane based products. Those ones are very fluid and do not need thinner or very little.
The ones I use sometime are 2 composants , + eventual tghinner.

Nitro is only working with solvents evaporation (and the product that tense itself).

Very hot weather is causing trouble with Nitro and shellac, probably less with PU (I am not much used to those anyway)

Regards
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#2120293 - 07/19/13 07:00 PM Re: refinishing nitrocellulose [Re: Jon Page]
Olek Online   content
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Registered: 03/14/08
Posts: 7426
Loc: France
Originally Posted By: Jon Page
So, I take it, you're not using paste wood filler to close the pores and going with an open-pore finish. You'll want to remove that shellac stripe before doing the whole lid, it may show otherwise.


you can fill with pumice powder and shellac, no need to sand as with wood fillers.
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#2120298 - 07/19/13 07:04 PM Re: refinishing nitrocellulose [Re: OperaTenor]
Olek Online   content
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Registered: 03/14/08
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Loc: France
Originally Posted By: OperaTenor
Originally Posted By: Minnesota Marty
Jim,

I have been giving a lot of thought to your statement that shellac is the most prone to 'checking' or 'crazing,' and I put that back in the context of 1936. From the turn of the twentieth century, shellac was rarely used in furniture building, it was most common for wall paneling or floors, though varnish was considered a better option for those uses. Shellac is a very soft finish and scratches easily. Checking is not usually considered one of its characteristics.

By 1936, Kimball would most certainly be using sprayed nitrocellulose lacquer, the product developed by Dupont, rather than the traditional formulation of lacquer as used in the nineteenth century. Shellac, as used in a traditional "French Polish" was very rare in the US and not used by piano builders or cabinet/furniture makers.

On the piano that you are working on, is the solvent for the finish alcohol? Often small cracks can be repaired as a surface treatment using alcohol and very fine steel wool. These finishes will rarely develop the large scale 'alligator' checking as will a lacquer finish from spending many years in direct sunlight.

So, I've been curious about your experience and would very much like to hear your thoughts.

Cheers,


Yes, I'm using denatured alcohol to strip it. If you go to my No Piano Left Behind Facebook page (and like it, of course laugh ), I have photos of the work I've been oh so slowly doing on it.

I chose to strip is rather than just smooth it out because the finish had darkened, and it was difficult to discern the wood grain anymore. I am going to refinish it with shellac as well; I really like working with it.


Here's a sample, showing the comparison between the existing finish and how it looks stripped/refinished:



that way you keep the undercoat I suppose, as usually it is better to strip with a stripper, often the old shellac is whitened, and anyway your new shellac will build up more nicely on bare wood,more transparency, better shine, etc

Keeping the bottom is good for black case, and even then sometime it cause trouble and the surface is not tense enough.

the coat seem to be thin anyway
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#2120394 - 07/20/13 01:11 AM Re: refinishing nitrocellulose [Re: berninicaco3]
OperaTenor Offline
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Registered: 04/13/06
Posts: 2380
Loc: Sandy Eggo, California
I guess I should have clarified; that "finish" strip in the photo is just water. Just to show what it would look like finished.
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#2120453 - 07/20/13 07:57 AM Re: refinishing nitrocellulose [Re: Silverwood Pianos]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7426
Loc: France
Originally Posted By: Silverwood Pianos
There is no interest in my experience or postings here so this was not posted earlier;

For what it’s worth;

Wiped down with methyl hydrate would have cleaned off all the oils, dirt, fingerprints, etc. and left the old surface absolutely clean.

When the methyl evaporated it would have left white streaks which is the old finish grabbing moisture out of the air as it evaporated. This reveals the old surface is softened by the methyl and can be re-started.

When a new coat is sprayed over top this releases the trapped water and the blush disappears. The first new coat would have revealed all of the divots and bumps which are then filled with clear or sanded down. Then the second coat would get the skating rink.

Only good for 5 years. If the old finish was flaking off maybe trouble coming before that time. Flaking reveals lack of adhesion. Makes for an unstable base coat.

Mixing nitro 1 to 1? That is 50% reduction and have never heard of that.

Hello orange peel……

Most lacquer products can be used straight out of the can or 10% reduction. 30% if you want to use as sealer coat.


I did the same with some amalgamator. With good success. Same principle, without whitening..
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#2121072 - 07/21/13 03:08 PM Re: refinishing nitrocellulose [Re: berninicaco3]
Olek Online   content
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Registered: 03/14/08
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Loc: France
amalgamator "egalisateur" (a very light pass with 1500 grit MIrka, before.
Then sprayed stained Nitro satin lacquer.
That bench was yellowish , more light and ugly lemon color like.

Too bad if it is supposed to hold only 5 years, I hope for more ! ...
Very robust bench as was done in the 80's



Edited by Olek (07/21/13 03:09 PM)
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#2121074 - 07/21/13 03:13 PM Re: refinishing nitrocellulose [Re: Jon Page]
Olek Online   content
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Registered: 03/14/08
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Loc: France
Originally Posted By: Jon Page
So, I take it, you're not using paste wood filler to close the pores and going with an open-pore finish. You'll want to remove that shellac stripe before doing the whole lid, it may show otherwise.


I used cellulose paste filler, and did not like it much, as it tend to mask the wood, (it is mostly talcum and nitro lacquer)I would use it when the veneer is not first class. We use products that can be sprayed, to close the grain and isolate the bottom.
they also contain some powder, something that makes them thicker and make sanding easy.

On nice old pianos we can find sawed veneers , they are thick, but also they catch very nicely the light as the fibers are not crushed as with sliced veneers . they deserve a nice finish for that reason.


Edited by Olek (07/21/13 03:15 PM)
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#2122159 - 07/24/13 03:20 AM Re: refinishing nitrocellulose [Re: berninicaco3]
phacke Online   content

Gold Supporter until November 11 2014


Registered: 10/18/12
Posts: 492
Loc: CO, USA
Originally Posted By: berninicaco3
BTW, as an update:
repairing the old finish seems to be working out nicely.
still getting a hang of spraying smoothly.

But the first results are taking, no fisheyes, no delamination. If it crackles in several years... I'll be OK. I kinda liked the crackle anyway.
What I didn't like was the damage and the flaking.


Hello, berninicaco3 -
Are you still there? I was wondering if you determined the nature of the finish you had on you piano originally (Lacquer vs shellac) and what brand lacquer you sprayed on.

Best wishes -
_________________________
phacke

Steinway YM (1933)
...Working on:
G. F. Händel: Suite in G minor (HWV 452)
J. S. Bach, Sonata No. 1 in B minor (BWV 1014) duet with violin

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#2122160 - 07/24/13 03:34 AM Re: refinishing nitrocellulose [Re: Olek]
phacke Online   content

Gold Supporter until November 11 2014


Registered: 10/18/12
Posts: 492
Loc: CO, USA
Originally Posted By: Olek
Originally Posted By: Silverwood Pianos
There is no interest in my experience or postings here so this was not posted earlier;

For what it’s worth;

Wiped down with methyl hydrate would have cleaned off all the oils, dirt, fingerprints, etc. and left the old surface absolutely clean.

When the methyl evaporated it would have left white streaks which is the old finish grabbing moisture out of the air as it evaporated. This reveals the old surface is softened by the methyl and can be re-started.

When a new coat is sprayed over top this releases the trapped water and the blush disappears. The first new coat would have revealed all of the divots and bumps which are then filled with clear or sanded down. Then the second coat would get the skating rink.

Only good for 5 years. If the old finish was flaking off maybe trouble coming before that time. Flaking reveals lack of adhesion. Makes for an unstable base coat.

Mixing nitro 1 to 1? That is 50% reduction and have never heard of that.

Hello orange peel……

Most lacquer products can be used straight out of the can or 10% reduction. 30% if you want to use as sealer coat.


Hello, that is interesting, but methyl hydrate is not availeable probably today in Europe, forbid, as many solvents.



Hello Mr Oleg,
An alternative to suck petrochemical organics out of wood, given in the series in the Piano Technicians Journal,
http://www.hancockrestorations.com/PDF%20Files/Hancock%20PTG%20Articles%201%20and%202.pdf

is Boraxo
http://en.wikipedia.org/wiki/Boraxo

Best wishes -
_________________________
phacke

Steinway YM (1933)
...Working on:
G. F. Händel: Suite in G minor (HWV 452)
J. S. Bach, Sonata No. 1 in B minor (BWV 1014) duet with violin

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#2122166 - 07/24/13 04:12 AM Re: refinishing nitrocellulose [Re: berninicaco3]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7426
Loc: France
nice reading , thanks. Better have good equipment indeed.

Our providers made new recipes for strippers, that are working fine, and are PH neutral (no washing)

I wash anyway with "Triton X" 2% soup usually. this is to get rid of old waxes. It also raise the grain.

filing is done with pumice and a lot of work. actually-very difficult due to the very warm temperature, the shellac build up before the pumice close the grain.

BTW methyl hydrate is also used in the article, borax only to wash the eventual wax residue, if I read correctly.

Borax is what makes washing powder, I believe.


Edited by Olek (07/24/13 04:14 AM)
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#2123622 - 07/27/13 12:59 AM Re: refinishing nitrocellulose [Re: berninicaco3]
phacke Online   content

Gold Supporter until November 11 2014


Registered: 10/18/12
Posts: 492
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After re-reading, Mr. Silverwood was referring to methyl hydrate to clean the old lacquer surface for respraying lacquer finish on top (without stripping to wood, so the conversation changed somewhere-I did not notice). By the way, methyl hydrate, is more commonly know as methanol, and I think it so common that it should be regularly available and used in Europe. It is even found in cheap vodka -- definitely not good to drink.
http://news.yahoo.com/methanol-kills-19-injures-24-central-europe-161534816.html

The PTJ article refers to methylene chloride, as a paint stripper/degreaser. Certainly much more agressive solvent than the methanol (methyl hydrate). Then Boraxo is still recommended for final cleaning to remove the silicones absorbed in the wood, after stripping.

Thanks for the information about Triton X. That is a pretty potent sounding marketing name, working at a 2% solution! I searched around a bit for it, and indeed it looks like it is used as such, in these particular cases on a finish, not on the wood stripped of its finish:
http://www.thehenryford.org/research/caring/wood.aspx
http://www.woodcentral.com/bparticles/save_finish.shtml

Mr Oleg, if you are using in it such a way that it raises the grain, then I presume you are talking about the case of using it on bare veneer wood.

Best regards-


Edited by phacke (07/27/13 12:03 PM)
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...Working on:
G. F. Händel: Suite in G minor (HWV 452)
J. S. Bach, Sonata No. 1 in B minor (BWV 1014) duet with violin

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#2123626 - 07/27/13 01:41 AM Re: refinishing nitrocellulose [Re: berninicaco3]
BDB Offline
Yikes! 10000 Post Club Member

Registered: 06/07/03
Posts: 21396
Loc: Oakland
The last time I worked on a lacquer finish, much of it had flaked off, and it was colored, so repair was impossible. I scraped most of it off, as I have become adept with scrapers.

The trick to using scrapers is to knock the corners off them. That is where they dig into the wood and cause problems. A pointed scraper can be used to get into corners.

If you use planes, taking the corners off the blade makes them easier to use, too. Most sources will talk about putting a curve on the bottom of the blade, but that is harder to do, and results in curved cuts. Just grind the last 1/8" of the blade at an angle which disappears under the sole of the plane.
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#2123787 - 07/27/13 12:19 PM Re: refinishing nitrocellulose [Re: phacke]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7426
Loc: France
Originally Posted By: phacke
After re-reading, Mr. Silverwood was referring to methyl hydrate to clean the old lacquer surface for respraying lacquer finish on top (without stripping to wood, so the conversation changed somewhere-I did not notice). By the way, methyl hydrate, is more commonly know as methanol, and I think it so common that it should be regularly available and used in Europe. It is even found in cheap vodka -- definitely not good to drink.
http://news.yahoo.com/methanol-kills-19-injures-24-central-europe-161534816.html

The PTJ article refers to methylene chloride, as a paint stripper/degreaser. Certainly much more agressive solvent than the methanol (methyl hydrate). Then Boraxo is still recommended for final cleaning to remove the silicones absorbed in the wood, after stripping.

Thanks for the information about Triton X. That is a pretty potent sounding marketing name, working at a 2% solution! I searched around a bit for it, and indeed it looks like it is used as such, in these particular cases on a finish, not on the wood stripped of its finish:
http://www.thehenryford.org/research/caring/wood.aspx
http://www.woodcentral.com/bparticles/save_finish.shtml

Mr Oleg, if you are using in it such a way that it raises the grain, then I presume you are talking about the case of using it on bare veneer wood.

Best regards-


Yes I always confuse methyl chloride, which is really forbidden now, and methyl hydrate , which is not sold under that name her , not easy to find but we have other alcohols, as isopropyl, that may be could do the trick (to clean and may be soften a cellulose finish) .

Triton x was sold to me if I need to use shellac or lacquer on a case that was waxed.

I use water on the wood once stripped, before sanding, to raise the grain (alcohol is only to have a better look at the wood and locate where traces of old finish are yet present.

Scraping is not enough to prepare for a new finish, often, mostly because the base, bottom coat and filler is what gives the whitish aspect .

scrapers are really excellent tools anyway.

Stripping shellac looks simple but alcohol based products go deep in the wood, so the stripping method must be good.

on that pic on the right the original veneer is particularly whitened. on the top of the leg the part is being stripped, the leg have been stripped, and the pore closed with pumice and shellac before polishing with more shellac

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