Is there some substance that would soften dried wood glue quickly to enable pieces to be taken apart?
John Brock: It depends on the glue. If it’s yellow or white glue, soaking in white vinegar for a while softens it up pretty quickly. If it is hide glue, then a little warm water will do the trick. If it’s a polyurethane based glue like “Gorilla” glue, then nothing will soften it. Epoxy is another one that won’t soften.
Michael Dresdner: Don’t forget heat, which will soften hide glue, white glue, and epoxy, though not moisture-cured polyurethanes. Of course, the problem is getting enough heat to the glue line without destroying the wood. For hide, white and yellow glue, many luthiers drill a small hole to the glue line and use a needle tip hooked to a cappuccino machine to get live steam to the site. Sadly, that won’t work with epoxy, which needs about 300 degrees F before it lets go.