That is some great information in that article, Jim! I'll have to keep that in mind should I ever go off on a tangent and decide to build a greenhouse. I wonder if Rustoleum's "plastic" paint would work. I would think you would need to have the framework setup with all the bending done so that when you paint it the paint won't crack from bending.
I'm not planning a greenhoues but that would be a bad experience (and $$ loss) to go to all the trouble of building a greenhouse only to see your work turn into tatters in a year or so!!!! Thanks for the heads'up!