I mixed a 2# cut of shellac. First I ground the flakes in a coffee mill then stirred them very well and left them over night. The next day there was a glob in the bottom of the jar which won't dissolve no matter what I do. I thought shellac flakes had a very long shelf life. These have been kept in a cool place for 2 or 3 years. Could this be the problem?
Shellac does lose its solubility, although I've never heard of a problem after such a short time. I can tell you for sure that 20 years is too long to try to keep them alive. My old shellac became nearly insoluble after that length of time.
As long as it dissolves, it's good to use, so you could try heating the alcohol, but best practice would be able to get new stuff.
Same thing happens to old shellac finishes. They can lose solubility after time.
How old is your alcohol? It picks up water every time it is exposed to air and needs to be considered too. I only mix up a small amount at one time in a plastic squeeze bottle and don't dump all the shellac into the alcohol at once. It stays in my pants pocket until all the shellac has been added and is dissolved. This keeps it in motion and warms it.
Thanks for both of your help. I never considered the alcohol, it's a few years old.
Here's an excerpt from an article Leonard Lee wrote on importing shellac.
In addition to lightening shellac, the refining process also affects the shelf life of the product. The more refined the shellac, the shorter its shelf life.The most highly refined forms (blonde and white) seem also to be less durable than the other grades.
We find many interesting items (besides random bug parts) in our shellac when we repackage it. Sometimes there is a feather or two, an empty match box, or scraps of paper. But the most interesting find was the cigarette butt shown at the lower left hand corner. It is a hand-rolled leaf held together with a white thread. Among the Hmars, a tribe in the northeastern Indian states (where lac bugs abound), the color of the thread used to wrap a cigarette plays a special role in courtship. Green or blue symbolize reciprocated affection; red stands for rejection and white is neutral - a "wait-and-see" color.
Apparently, the cigarette that excites a Hmar man most is wound with a hair from a woman's own head; this indicates unequivocal acceptance of the suitor's approach and the promise of undying love.
Ah, yes, the untold stories in a bag of shellac!