Non warped acetate kits

[ZTony8]

I was looking at my two old Revell Highway Pioneer kit sets from 1953 and wondered why, after 69 years, these built and unbuilt acetate models haven't warped at all. My first thought was that it was because most of the parts were molded thicker than the promos that were molded in acetate. But then I saw some thin parts and they're not warped either.  Anyone have the answer?

 

[Ace-Garageguy]

More than anything, specific storage conditions of temperature and humidity influence the deterioration of acetate models.

I have an early acetate Midget from Monogram that's almost perfect, and another one that's badly warped and shrunk. I acquired them at different times, from different sellers, but they were made at the same time, though were stored differently.

The closest thing I've found so far as to the actual "science" regarding the deterioration of models is a site looking at factors contributing to the deterioration of acetate film stock.

https://s3.cad.rit.edu/ipi-assets/publications/acetate_guide.pdf

 

[ZTony8]

21 minutes ago, Ace-Garageguy said:

More than anything, specific storage conditions of temperature and humidity influence the deterioration of acetate models.

I have an early acetate Midget from Monogram that's almost perfect, and another one that's badly warped and shrunk. I acquired them at different times, from different sellers, but they were made at the same time, though were stored differently.

The closest thing I've found so far as to the actual "science" regarding the deterioration of models is a site looking at factors contributing to the deterioration of acetate film stock.

https://s3.cad.rit.edu/ipi-assets/publications/acetate_guide.pdf

 

I don't remember exactly when my aunt passed these sets to me (they were Christmas gifts to my grandfather in 1953) but I think I got them when my aunt and grandparents moved in 1973. The basement in their old house was always warm, my Mom's basement was decently warm but my basement where the kits have been since 1987 is decidedly cool (below 69 degrees) but dry. BTW the Pactra paint set supplied in the one kit set is still good!