Shellac Flakes

[Frank Weston]

BSimon1234@aol.com wrote:
> 
> Someone said:
> <<I've used thickly-mixed shellac flakes for player piano work. It seals
> well, but
> takes forever to harden. I wonder why it isn't sold already prepared?>>
> 
> I understand that shellac, especially orange shellac, degrades in it's
> solvent, alcohol, quite rapidly over time. Years ago for player work I tried
> several products that stabilized the liquid shellac, but they did not work
> out.  That was so many hears ago that I cannot remember just how they proved
> useless.
> 
> If shellac does indeed degrade quickly in alcohol, it wouldn't be too
> difficult to conduct a shop experiment. Just use the same solution and apply
> to different sections of a board every few days. ( I think it might even
> precipitate in the "jar", but perhaps not.
> 
> Bill Simon
> Phoenix

The problem with old shellac is that it will not harden properly.  Once
shellac is mixed with alcohol, a chemical process in which the shellac
resin converts to a soft, flexible plasticizer (goo) begins.  This
process continues until all of the shellac is converted.  As more and
more shellac becomes goo, the film formed by the shellac gets more and
more rubbery, and finally a point comes when the shellac will not dry at
all. A suspension of shellac in alcohol is what is desired, not a
mixture of the converted resin.

I find that I get best results with shellac mixed from flakes and
allowed to stand 24 hours.  After a week, I discard what is left,
although many references say mixed shellac is good for about six months.

No need to do an experiment,  I've already made all the mistakes.  Just
mix from flakes, and mix only what will be quickly used.

Frank Weston