Sunday, May 15, 2016

Dimensional Stability

I was doing a little cleanup in the office yesterday and noticed something on my research shelf of Family Arabian Foals:

The variable heights aren’t the big news here: most of us know that Cellulose Acetate is susceptible to shrinkage, both during and after molding. It’s more a quirk of the manufacturing process than a concern, unless it is also accompanied by paint discoloration, distortion, and oozing that indicate the model may be suffering from the dreaded “Shrinky Syndrome”.

What’s interesting is the composition of the tallest member of this little crew: according to his “B” mold mark, he’s molded from the Cellulose Propionate plastic.

It hadn’t occurred to me before, but that makes a lot of sense.

Breyer briefly experimented with this slightly different Tenite cellulosic plastic in the late 1970s and early 1980s, with mixed results. It was more widely available and had greater dimensional stability, but was also more brittle and difficult to finish/work after molding.

Better dimensional stability means less shrinkage and warping.

What that means for us is that this Foal is the most accurate depiction, dimensionally, of what the interior of the Family Arabian Foal’s mold actually looks like.

I now find myself almost intrigued enough by this idea to seek out other Propionate models and cross-compare them with their more standard Acetate counterparts.

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