Intercrystaline, it sounds quite nice doesn’t it? But, the fact is its bad news if you have it!
Most collectors of diecast vehicles know about the perils of intercrystaline corrosion although it is almost always wrongly referred to as metal fatigue and is usually associated with pre-war Dinky models and the like where a model is covered in a crazing pattern. It can also show as one small imperfection in the metal that blows out leaving a round pock mark in the surface. I have only seen this type on the base of a Morestone Noddy car but have heard of it on other makes.
Sadly, it seems this problem has not been confined to the past and when I recently cleared out some of my childhood Matchbox cars I found that one of my favourites, a 1990 Chinese made Nissan 300ZX which although well used had hardly a mark on it was now swollen and misshapen and covered in crazing.
You won’t necessarily see the problem though, it can just make the metal very brittle without initially affecting the appearance. A 1980s Gama model of a Nova SR that I recently bought looked to be still as new with no sign of any problems, but I managed to drop it when I was inspecting it, and whilst it only fell from a seated position onto carpet it practically exploded into a dozen small pieces!
Another recent discovery is the Oxford Diecast Morris van (featured image)which had never been out of its box before but had swollen and crazed all over, the more surprising thing about this is that both the body and the base plate were both affected. As these are separate parts I would have expected them to have been made at different times in different batches so it’s unlikely for both to have the problem. The picture on the left shows just how weak they become, I shattered it with just hand pressure on top of a piece of wood (with gloves and safety glasses on of course).
The Auto Pilen Seat I recently bought for spares was also surprising in the way it had been affected, only one door had corroded and expanded but as it did so it buckled the whole body shell of the car before the door fell apart. I have since seen another identical model on eBay with the just same door affected by corrosion and nowhere else.
Of more concern than the cheaper models I have just mentioned is the modern high-end examples which are crumbling and could result in some serious financial loss for their unfortunate owners. I had a 1:18 scale Ford Escort MkII which looked fine on display for several years but then one day the boot lid just fell into two pieces! As some of these models change hands for a few hundred pounds then it is a serious concern for collectors. A quick look on google images shows a very worrying array of models from many manufacturers which are self-destructing although a few of them look rather pleasing in an arty way but not if they were your own prized possession I dare say.
I can allay one fear though, it’s not contagious as some people seem to think. It cannot spread through your collection. It is simply down to a poor-quality batch of metal.
We’d love to hear from you if any of your collection has suffered from this kind of corrosion? Leave a reply in the box at the bottom of the page!