The Little World

Or ” Are You Stuck With it? “.

A recent question on Phil Flory’s YouTube channel about dissolving old glue on a model kit – really old 1950’s Testor cement – was ably handled by the team of English modellers when they advised the questioner to put it away for another 50 years and wait for it to come apart naturally.

That’s actually funny enough to be true. I’ve watched plastic kits adhere and fall apart for years and I would also like to know the rhyme and reason for it all. The things fall into two categories”:

a. Together then, apart now.

I bought a number of Plasticville buildings from eBay – new kits, not 50’s leftovers. They’re lovely and have an interlocking sistem for the corners of the walls. Just as well, when I glued them together with standard Humbrol tube cement they lasted all of a year and then popped apart at those corners. The Humbrol glazed the plastic but did not bond it. I tried Revell Contacta next. Same thing. I couldn’t believe that what seemed like standard plastic could be that resistant.

Eventually I got out a urethane glue that has worked, albeit with some bubbling.

b. Together then, still together. I still have a few leftovers from the 60’s – and I don’t know why they were not thrown away at the time. But they were stuck with Airfix cement from little rubbery vials in the kits – and they are irreversibly welded.

The occasion for redoing a kit comes up more often than you’d think – indeed there are times when you want to reverse a step even as you build. I have no idea whether use of newer cements like Tamiya Extra Thin will allow this. Indeed I have no idea whether I will go to the museum one day and find all the wings fallen off all the aircraft.

I would like a release agent, but I suspect that the cements weld at a deeper level. Cyanoacrylates can be debonded with pressure and/or acetone, but then acetone can attack styrene as well, so you might be making a worse mess.

In cases of prescience – when I suspect I will want to re-do something sometime, I resort to using Weldbond white glue and fairly big glue patches. You can revitalise this with plain water. It’s saved a mistake more than once.

c. No bond, Mr. Bond

The plastic that Lehmann used for their LGB train sets was a special type – a tough Lexan of some sort that resisted wear. It also resisted any conventional solvent glue. I remember that when they did have to glue something they used a form of urethane or of rubber cement. As a result, these joints could yield to heat and solvents when we needed to repaint or redo a car. Major rebuilds need careful fitting to provide places to glue or screw on new panels. The plastic was great as a toy, but a pain to model with.

This also applies to some forms of plastic sold as scratchbuilding material. They have great extruded shapes, but you need especial glues that no-one carries to assemble anything. As a result, I avoid them.