Back in the good old days, (whenever that happens to be for you!) it was common to see in instructions and building articles to add three to five drops of castor oil to thinned dope for the final colors and clear, to act as a plasticizer. The Southern R/C product that was mentioned was probably Dave Brown Flex-All. The Sountern R/C products, Dave brown Products ab some others are all under the umbrella of Ohio Superstar Products or something like that. I may have that mixed up. I have tried to get the hobby shop to find me some flex-All but apparently they only deal direct now. The last time I used it, it looked just like medicinal castor oil, fairly clear. A drop of each on the tip of my tongue tasted the same. Mot very scientific, I know, but it was some way to test it. Bill Byles sent me the name of a chemical to use for a plasticizer, but I couldn't pronounce it so I know i can't remember what it is! I'll see if I can dig that up and post it on this thread.
Type at you later,
Dan McEntee