Dope Selection Help

I use Sig as much as I can. Why? It works the best and has the highest fuel proofing qualities I've found. NO dope is fuel proof. When dealing with 1/2A, high nitro fuel is like lacquer thinner. All of my top coats are Sig Lite Coat. Sig Lite Coat is a the clearest of clears next to Brodak Crystal Clear and it has proved to me to be the highest in fuel resistance. Randolph makes Sig and also Brodak.They all have different working, drying, and spraying characteristics that are different between them. I prefer Sig due to it's brushing characteristics, it has the slowest  dry time. This allows for less blushing and a shinier overall finish and the option to go back into the work without it dragging. You can't do that with Brodak. Brodak also and almost always requires an additional product ( retarder) to brush and dry properly.  Randolph usually has tint in their clear unless specified not to. Butyrate shrinks forever but when Sig Lite Coat (Non taughtening)  is used as a final, it prevents the twisting and warping that can take place. Sig Lite Coat can be used on planked surfaces from start to finish. It will not shrink wrinkles from silkspan or tissue. On freeflight models I use Sig Lite Coat exclusively. It has that low of a shrink rate. The Randolph butyrate your referring to would crush a freefight and even a larger model. It should be plasticized but I know many that use it just thinned from the can. If you don't require the need of a taughtening dope, I wouldn't personally use it then but that's me.  A solid planked wing while stronger than a framed wing in terms of torsional strength is still subject to twisting and warping. This can be greatly compounded for instance if you paint the model and place it to dry on it's gear. The top of the wing dries faster than the underside causing the solvents to be trapped underneath which causes the wing to twist.

                    I'm sorry if this was confusing, I was just trying to explain that dopes have other characteristics aside from their shrinking abilities and knowing what your dealing with is half the battle.