unbuilding models

Two ways, Solvent and physical/cutting.

Solvent requires a liquid glue or solvent that will break the bonds. It is generally messier and less exact, but certainly gets the job done.

Second, cutting. Buy a razor saw and chop away. This will remove about 1/32" -- 1/16" plastic down the middle, and this will need to be filled back in. This method is more precise, but requires some cleanup and filling afterward.

Either way, you're in for some work.

Nick,

When I screwed up the initial paint job on my Tiger I, I was advised to use brake fluid to remove the paint.  That worked great, but it also disolved all my glue bonds (except a couple where I used CA glue) and all the pieces fell apart so I had to reassemble the entire model.  It's a bit of a mess, but didn't damage the plastic one bit.  I used Tamiya extra thin liquid cement for gluing, so I don't know how it would work on any other kind of glue, but if your grandfather used liquid cement you might give it a try. 

TomB