By Maz Woolley
Photographs by the Author of a model in Dave Turner’s collection of Fords in MIniature.
Integranular corrosion is better known to collectors as “metal fatigue” or “zinc pest”. The alloys used for diecast models (Mazak/Zamak) should be stable and models should remain fine for years unless impurities exist in the alloys. Many of us became aware of this phenomenon when collectors of early Dinky models watched their models disintegrating before their eyes. Since when the same has been seen in other ranges with pictures of broken and fatigued Saratov produced USSR models featuring on some bulletin boards for example.
Many collectors, including me, had believed that modern mainstream die casters quality control was a guarantee that such problems would not arise. But it isn’t true. The pictures below are of a Corgi model which is gradually failing but Corgi are not the only people whose models have issues, and the failure of the model below should not be taken as an indication that your stored Corgi models are any more at risk than other makes.
The Millionth Transit was a popular release from Corgi but as can be seen from the photographs below this one it is suffering so badly from the corrosion that the sides are bowing out and the bonnet and roof are wrinkled.
Things are a little complicated by the fact that it appears that poor preparation or paint issues by some makers may cause the paint to lift and craze whilst the casting below is still actually in good condition. However, as the pictures above show when the metal starts to fail the surfaces become “wavy” which means that it is not just a problem with paint.
Many collectors, myself included, have models stored in boxes. It may be worth your while looking over models that you have not looked at in a while to check that they are all OK. If you should find models with Intergranular corrosion please let us know by email or facebook or via the contact form on the website. It would be interesting to see pictures and perhaps do a round up of the wider experience of collectors at a later date.
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