Does Shellac Crack?


I was wondering can shellac crack over time? My father found this nice looking hutch but the finish is cracking on it. He ask me about and I said it could be shellac, but I am not sure, how can you tell what type of finish is on an old piece of furniture?

Jeff L Headley

Well-known member
What do you mean by cracking. It is probably a 50 to 100 year old vanish finish which cracks and crazes within that time frame. This is why I don't like most older and many newer varnish finishes. Easy to apply but hard to repair without abrasives. Would the finish be a dry desert cracking (large patches with large cracks in between or an alligator skin cracking (lots of small crazing with many small cracks) or just a lizard skin( bumps and rough with fine lines)cracking each mean different things? Please remember alcohol dissolves shellac and not a varnish finish. Be careful applying alcohol  to your surface if it is shellac. Try a hidden area first alcohol will remove a shellac finish quickly.
Please lay out whatever rags you use to dry individually. IF YOU WOULD BALL THEM UP THEY WILL SPONTANIOSULY COMBUST!!!


Jeff Wrote "Please lay out whatever rags you use to dry individually. IF YOU WOULD BALL THEM UP THEY WILL SPONTANIOSULY COMBUST!!! "
Is this correct? I know that oil finishes dry through an exothermic reaction that  may release enough heat to ignite rags, but I don't believe this is a hazard with shellac. The hazard with shellac (and with lacquer as well) are that the vehicle in which the shellac is dissolved (ethanol) is quite flammable. I can't find (after a quick Google-search) anything about the flammability of the shellac resin. I know lacquer resins can be quite flammable so we need to take cautions when spraying lacquers, but I don't know whether the same cautions are required for shellac. I think brushing or padding either is pretty safe.

I don't know a lot about wood finishes, but from my chemical engineering education I understand a little about chemical hazards. I think it's important to take appropriate precautions, but I don't think we should worry about things that aren't a hazard (i.e. shellac rags).


Well-known member
Shellac will not spontaniuosly combust but I take the approach in my shop that all rags are potentially combustable for those rare times that I actually use straight oil.