Bushing cloth glued with rubber like cement

Posted by: Olek

Bushing cloth glued with rubber like cement - 11/02/12 06:53 AM

A friend have trouble to unglue mortise bushings on an old NY Steinway.

He state that the glue stay sticky / tacky (he use acetone to moisten the bushings I believe) difficult to clean.

Any one meet that problem ?

I lately use a mix of aceton, alcohol and water to unglue the cloths when they are glued with PVCE glue, as often, it works after 2 or 3 passes and does not close the wood as when moisture is used (no stain, also)

But on a rubber like cement ? I thought of mineral spirit mixed with aceton, never had that problem in fact...

Thanks for your ideas
Posted by: UnrightTooner

Re: Bushing cloth glued with rubber like cement - 11/02/12 07:13 AM

Naphtha (gasoline, lighter fluid) should dissolve rubber cement, if that is what it is. Just be sure to have PLENTY of ventilation. The vapors are extremely explosive and may also contain benzene, a carcinogen. (I used to work on oil tankers…)
Posted by: Olek

Re: Bushing cloth glued with rubber like cement - 11/02/12 07:21 AM

Thank you, yes IF it is that kind oc cement (surprises me)

Naphta is forbidden here, now, may be only in small quantities for lighters,

but we can find mineral spirits, and also a replacement product sold in place of trichlorethane (which is alos forbidden now)

This is a product that smell really bad, seems to be oily but does not leave any residue, possibly it will dissolve rubber cements also ( does not evaporates too fast)

is heat doing anything on rubber cements ?
Posted by: UnrightTooner

Re: Bushing cloth glued with rubber like cement - 11/02/12 07:36 AM

Originally Posted By: Kamin
.....

is heat doing anything on rubber cements ?


A little might make it more gummy, a lot will result in a call to Kluge. wink

Mineral spirits might work, given enough time. Gasoline should work better.

Where is Mark R. when you need him?
Posted by: Mark R.

Re: Bushing cloth glued with rubber like cement - 11/02/12 09:43 AM

Oh, I'm right here, Jeff, and I did read the question earlier, but I hadn't responded yet, because I'm really not sure what type of glue we're talking about here. I don't want to dish out inappropriate advice to someone working on a Steinway.

Some questions / comments:

... The NY S&S might be old, but are the bushings original? If they are, would that make it some form of collagen glue?
... Isaac said it may be PVC-E. Then a solvent such as acetone or MEK (methyl ethyl ketone) should work to soften the glue, because that's what they use to "solvent weld" PVC. Another option would be THF, but that's not generally available to the public.
... What do you mean by "rubber like" and "rubber cements", Isaac? From what I read, rubber cement would not at all be suitable for gluing bushings into key mortises. It is easily peeled off the surface.
... If it's some type of PVA glue (carpenter's glue), to my mind that's a problem. I've heard of acetone, ether, and organics [Edit: aromatics] (benzene, toluene) being used, but haven't tried this myself.
... If it's contact cement, acetone, MEK or lacquer thinners may work.

Chances are that solvents might soften a cured synthetic glue, but not truly dissolve it. So it would still have to be scraped from the wood.

Sorry, I can't be more specific (and wouldn't have joined the thread at all if I wasn't summoned wink ).
Posted by: BDB

Re: Bushing cloth glued with rubber like cement - 11/02/12 11:46 AM

How old is the piano? Have the keys been rebushed before?
Posted by: Olek

Re: Bushing cloth glued with rubber like cement - 11/02/12 12:58 PM

Hello, I apologize not being able to be more specific, as I asked for a friend, who was experiencing difficulties with the glue hard to soften, staying tacky even when moistened.

But the general conversation was useful anyway.

I just took off cloths from a Yamaha C3 with a mix of commonly availeable products: acetone; water and alcohol.

No heat, no wall paper remover, no acetic acid (because of the stain it leaves on some woods I avoid those)

The solvents and water not only soften the glue, but allow the cloth to be peeled off with the glue remaining on it, no scraping or cleaning is due (or very little)

I have MEK at the shop, and I will try that next time ( I am working on site now) I suggest that the mix water plus alcool moves the wood fiber, so the softened glue loose its grip, I made some with only acetone, it was less easy.

I will let you know what my friend used and how old was the piano...

For the PVC E glues I generally find that strong heat works very well, the glue get very soft, but it is not very practical for keys, and I like to keep the wood in its original shape and thickness, when using heat and water the wood thickens (and the keys may warp a little, solvents are advantageous;
no need to use sizing cauls, then a little hair dryer to get rid of moisture, and the new cloth can be glued really quick , I guess the complete keyboard took 3-4 hours, but with PVC glue, and not counting the time elapsed while the products where softening the glue)

i used the little Japanese chisel to peel the cloths (sold by Pianotek or Jahnn)

Thank you for you answers, gentlemen



Posted by: Olek

Re: Bushing cloth glued with rubber like cement - 11/02/12 02:40 PM

The S&S was only 40 years old, original cloths, my friend used a lot of differnt products mixed, plus heat wink

I have seen pre glued strips of bushing cloth, intended to be used on machines. the glue is very thick (to me) and ask for a lot of heat to glue. (more heat than I would use on bushing cloth)

I suppose it hold really well once glued, possibly this was that kind of glue, I have no idea of the sort of glue that is used there hot melt, but what will dissolve/soften it later ?
Posted by: BDB

Re: Bushing cloth glued with rubber like cement - 11/02/12 04:37 PM

Water. Use water with a bit of dishwashing detergent as a wetting agent, and let it sit until the cloth comes off.
Posted by: Olek

Re: Bushing cloth glued with rubber like cement - 11/03/12 04:37 AM

detergent, yes it may work;.. I use water usually but with alcohol as wetting agent, then nothing remains in the wood once dry, but small quantity of detergent may not harm probably.

What I like is not to put too much water, so I use little felts in the mortise to keep the water more on the cloth side than in the wood