What gloss coatings used on pianos built before WWII?

[hdpsr7]

I am just curious as to what type of gloss coatings (finishes) the manufacturers put on their pianos, especially those build in the 30's and 40's. I do not believe polyurethane was available during these periods. I ask this question because the original gloss finish of my piano now is dull but very textured.  The finish has wrinkles like tiny bubbles - due to heat, sunlight, age.  I really like this look and feel. The finish is still very glossy on the wood sections where the piano cover fold over itself.  Thank you.

[silverwoodpianos]

Either varnish that was rubbed out or orange shellac. In order to discover which of those two it is you would have to test with some solvents.
Checkering is common with old finishes of this type.

[richard black]

Hahahahaha! Dan, just spotted your tagline - that's brilliant! I hereby give notice that I may shamelessly recycle it at some point, indeed several points, in the future.

[silverwoodpianos]

Hello Richard,
Ha! …..yes thanks for the comments…………Feel free to use whatever parts you like.
Cheers,

[rachfan]

With the old lacquer finishes, the alligatoring effect (commonly seen on pianos from the 1920s) resulted simply from exposure to light over the years.  This is why an area such as the unseen back of a fallboard on a grand, looks perfectly normal--no light exposure there!  Alligatoring does't stop, it keeps progressing over time.  If it's a mild case, sometimes applying Liquid Gold or a similar treatment will restore the finish's luster temporarily (only until the next application is needed), but the only real solution is to strip the case and refinish it which is an expensive undertaking.

[hdpsr7]

Upon close examination, the finish of my 1940 Chickering has the "alligator" skin pattern.  Thanks for the info.

[silverwoodpianos]

With the old lacquer finishes, the alligatoring effect (commonly seen on pianos from the 1920s) resulted simply from exposure to light over the years.  This is why an area such as the unseen back of a fallboard on a grand, looks perfectly normal--no light exposure there!  Alligatoring does't stop, it keeps progressing over time.  If it's a mild case, sometimes applying Liquid Gold or a similar treatment will restore the finish's luster temporarily (only until the next application is needed), but the only real solution is to strip the case and refinish it which is an expensive undertaking.

Not exactly the case.What I do know is that spray nitrocellulose lacquers started being used on some production furniture as early as 1900, by the 1930s it was in common use.  

Nitrocellulose lacquers chemically are related to film celluloid and cellophane.   The nitro used on pianos was a mix of 80/20 nitro and white shellac (no wax).If the content of the mix had too much white shellac, the mix dried to brittle and this was the major cause the checkering or alligatoring effect.

Oh sure, UV light, heat exchange, and age all contribute to the damaging of finishes of all types; the trouble with blaming UV light as the only source, one would have to see the colour stripped away too, because UV will strip colours completely away. Many instruments can be viewed that have checkered finishes and the colour remains strong as ever.

I have refinished many an instrument that was placed into a window and one side is a completely different colour than the other while the finish remains the same on both………