A tale of two solvents

Yesterday, when I put finish on the comb handle, I imagine that some might have wondered why I didn’t put finish on after everything was off the lathe and epoxied in.  The reason is because of an interesting property of shellac and epoxy.

I don’t really want epoxy slopped everywhere when I apply it.  But some inevitably gets exuded.  If it gets on the bare wood, I can mop it up with some mineral spirits, but especially on an open-grained wood, it can be hard to get it all, leaving little shiny spots later (an aside, I’ve seen epoxy used as the finish for gunstocks before.  Interesting but labour-intensive) under whatever finish I’m using.  If I were to put an oil finish on in the lathe, then using mineral spirits to mop off the excess epoxy can cause blotchiness.

But, the solvent for shellac isn’t mineral spirits.  It’s alcohol.

So, if I put shellac on the handle while it’s on the lathe and let it cure, I can get epoxy on it and it will wipe right off with a little mineral spirits (because the shellac has sealed up the grain and is slicker ‘n grits), and it won’t hurt the finish at all because the mineral spirits doesn’t act on the shellac.  It’s a quick way to get everything done with a minimum of fuss.  I don’t like using epoxy much, but when joining dissimilar materials, there’s not much way around it.  This lot of grooming brushes I did for a shop last year was put together the same way, and came out just as well.