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'A gaping silken dragon,/Puffed by the wind, suffices us for God./We, not the City, are the Empire's soul:/A rotten tree lives only in its rind.'

Thursday, 19 February 2015


... perished tracks...

In response to my post about the 20 year old Matchbox Panzer III (next up here at the Hobbit bunker), DaveM brought up the issue of perished tracks in old kits. He says:

'Further to your comments about long term kit storage. I've never had too much trouble with really old decals. Sometimes a bit of yellowing but this can often be cured by a good dose of direct sunlight. But I would recommend storing them separately from the kit. And I would also advise storing vinyl and rubber tracks separately or at least isolating them (eg in polythene) from the rest of the kit. One theory is that some of those batches of Matchbox kits (eg M16) where the tracks disintegrated in the box was due to interaction between the tracks and residue from the mould ejector medium on the plastic parts of the kit.'
These interesting points brought to mind a 'First Principles' column written by Bruce Quarrie in Airfix Magazine in the early 1970s. I sorted through my small pile of those classic magazines, and found the article, which was, amazingly, on the same page as the Terence Wise article about Airfix engine shed conversations which I pictured just a few posts ago!  Anyway, what did Bruce Quarrie have to say 42 years ago:
'After two or three years a reaction frequently sets up between the plastic in which an Airfix tank kit is moulded and the flexible tracks. This reaction in due course actually "melts" the plastic from which the tank's wheels are moulded and, of course, ruins the model [...]'
Quarrie went on to recommend varnish before painting tracks and wheels, body etc. What is interesting here is that the problem seems to be manifest in disintegrating wheels, rather than tracks. Now, happily, I took Quarrie to heart all those years ago, and suitably sealed tracks and running gear, so none of my AFV survivors from the early 1970s shows any sign of decay. But did others experience melted running gear?


  1. Plastic rot really happens! I have been working on some very old Airfix Shermans (first issue without the later detailing of the hull) and the running gear has melted leaving the vinyl tracks looking as good as the day they were produced.

    Not wanting to throw away the kits as I think they still have some miles left in them I am attempting to camouflage the mess with a mud mix.

    Posts on my blog to follow.

    1. Paul, I had a look at the damage on your blog. It was amazing. I've not seen rot like that. Just goes to show, Bruce Quarrie was right all those years ago. But you did a nice job with the mud!

  2. Ah, now we're getting down to it - flavours and varieties of 'rot' ! I have had the melted wheels scenario where the tracks remain perfectly ok and I am pretty sure those were also Airfix Shermans with the silver vinyl tracks. If you catch it in time, you can just sand back the 'melt' and get a good protective coat of paint on before refitting the tracks. More advanced - well there's Paul's solution !

    I've also had tracks go hard and brittle. They will break if you just look at them funny. I don't know of a preventive measure for this as it seems to strike tracks that have been painted, varnished, etc. Best way of saving the kit is probably basing (and don't look at it funny). This seems more likely to affect the black rubbery tracks that Airfix in particular favoured for a while.

    Last of all is the Matchbox example I was mentioning where in the box the tracks just turned into something with the strength and consistency of a thin piece of soap.

    Cheers, Dave

    1. Words of wisdom Dave.

      I had to base all my Matchbox German halftracks and tractors due to the snap syndrome. Simple measure but t does the job.

      Fujimi tracks have a nasty habit of going very brittle and breaking as well. Some are so rittle they are like resin.

    2. Yes, brittle track syndrome. I've got a very old (40 years) Fujimi Valentine that was afflicted, despite paint and sand-based gloop that I'd added. Mind you, it could have been the sand-based gloop! But, given, Paul's comment below, it was probably Fujimi's fault. A good job I couldn't really afford Fujimi when I was a boy. All interesting stuff. What we really need is a chemist to explain what goes on.