I ordered some 5 momme Thai silk. That's the lightest they have, and it is for sure not pre-shrunk. I didn't ask about the heavier silks, but I made sure the 5 momme was not. I had been using a little heavier weight (6), but also from Thai Silks.
I brush three coats of unthinned clear on the perimeter of the wing, with a light sanding after the second. The silk is stretched on wet, and I finger rub thinned dope (about 50/50) over it. I take my time, making sure the underlying dope is getting hold of the silk , also making sure the silk remains damp until all edges are stuck down securely. I may start using only thinner for this step, in the future.
I let the wing dry completely, then rub in one more coat of thinned dope around the edges of the wing. From this point on, I've started spraying instead of brushing. The only problem now is that my equipment is too small for a large wing. I got a Badger air brush as a gift, and it has three sizes of tips, but even the largest delivers dope too slowly for a Flite Streak wing. It works fine; it's just too slow. I've ordered a larger spray gun, so that should speed things up quite a bit.
The point is this. Whether it's the lighter silk, spraying instead of brushing or just blind luck, those two coats of clear dope are now sealing the fabric very nicely and shrinking it as tight as I could want. In fact, on another wing I sprayed SIG clear on one side and Brodak on the other side. Once the dope was dry, I really couldn't see any difference between them.
I cut the SIG clear about 50/50 with SIG thinner. The Brodak had to be thinned (with Brodak thinner) quite a bit more, to get to roughly the same viscosity as the 50/50 SIG. I'm not sure if that means the Brodak clear goes further (using less of it) or if you just use more thinner with the Brodak. In any event, SIG's clear is quite a bit thinner, right out of the can.
Anyway, that's my experience so far. That doesn't make me any kind of an expert. I just tried to pick out the best of all the advice I had been given, then act on it. It looks as though it has put me on the right track.
That's it for the silk, at least for now. And now a couple flame-bait ramblings. (1) Ambroid forever! Always liked the stuff...still do.
(2) Let's put slow combat out of its misery, continue to fly a variety of local speed limit events, then settle on (very few, and of the most sensible) rules for a Nats speed limit combat.
I would think something like this would work well: 75 or 80 MPH limit, two or three laps timed before the start of combat. A realistic line length (60'?). Probably a shutoff should be required. They will eventually be mandatory anyway, no matter what speed combat is flown at. Other than that, fly whatever you like, powered by whatever engine you like, fed by whatever fuel system you like, with a tank (or bladder) placed wherever you like.
Optionally, you could set spacing from prop to leading edge and prop to hinge line at something like 10% and 50% of wingspan, respectively. That would keep super light, super turning, DOA Belchfire carbon fiber wings (or some such thing) from being developed just for the event. However, it would still allow the flying of literally any size plane.
With the exception of a shutoff (I just don't see them as simple quite yet), keep it extremely simple. It will tend to pull in more young people and more retreads like me. Face it, there really aren't many fliers with the abilities to handle Fast or FAI combat, financially or physically. But we hear about a whole lot of people flying "super slow" and telling us it's cheaper, easier and a lot of fun.
OK, that's it, and this time I really mean it. Light the fires...flame on!
Old but immature,
Denny Malott