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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.

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

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 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.

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 !

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.

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.

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?

Secretions from the Lac bug.

You Sir win three internets for a correct answer!

I think of it as lac beetle spit...

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.

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

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,

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.

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.

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.

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.

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.

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.