MIMF

I'm refreshing the French polish on my guitar and some need advice. I get a nice finish patina but the finish seems soft. it is easily degraded by body heat and humidity, more so than my other guitars that have French polish finish. I bought the shellac in flake form and mix it only when needed. Do the flakes go "bad" or is there a better grade of shellac that will not degrade so quickly??

This post was put in the birthday giveaway section. It might get more attention if it is moved to the glues and finishes section.

How long has it been since you finished the FP? Shellac will harden up over the next several weeks after you stop applying it. But. . . it sounds like it is softer than expected. Are these the same flakes you have used before when you didn't have this problem? Are they dewaxed?

I've moved this to the appropriate forum (thanks for pointing that out Bryan).

Another possible cause for soft shellac might be too thick a finish.

Don't know if waxed/ dewaxed, timeframe is one day

Bill Sylvester wrote:Don't know if waxed/ dewaxed, timeframe is one day

I'd baby it for a week, when it should be tough enough to cope with handling. Probably a month until it's "fully" cured. But it gets tougher thereafter, albeit slowly. After 50 years it should even be insoluble in alcohol.

Are you saying you have used these flakes on other FP projects and not had this problem? If so, other than the time the flakes sat around before this project did you do anything differently?

As Chris said, check it in a week and see if it has gotten better.

If I've misunderstood and you haven't successfully used these flakes before tell us the process you used to dissolve them (how long did it take for them to dissolve, what alcohol did you use. . .) and a bit about your FP process.

Even with dewaxed shellac flakes I like to use the method Alan Carruth had mentioned here to dissolve my flakes. I suspend my crushed up flakes in a cloth pouch/bag into my jar of Everclear so that it is submerged but at the top of the solution. As it dissolves, the dissolved shellac sinks into (and mixes with) the alcohol solution leaving any wax or other junk in the pouch.

I used denatured alcohol, Klean strip S-L-X, is it possible it could have gone "bad"?
I'm also curious about 2 lb cut, every where I look everyone uses it and then cuts it again when applying it to the rubber. Why not use 1 lb cut?

Over time alcohol adsorbs moisture out of the atmosphere. So it does go "bad".

As far as cut goes, I never measure when I'm mixing shellac. Keep in mind I am not an expert on FP by any means. In my mind, the cut really doesn't matter. All that matters is what is on the pad. You will be adding shellac and alcohol to the pad constantly through the process, always looking for the right amount. It is the kind of thing you get a feel for as you go and constantly adjust. Sometimes, if my shellac jar is getting low, I add more alcohol. Then I end up adding less alcohol to the pad while I am polishing. I usually leave the "tea bag" of shellac hanging in the jar so the shellac in the jar gets stronger for a while (so I add more alcohol to the pad). I recognize that this might be considered heresy so take it with a grain of salt.

Any recommended way to remove this French polish?