Thanks for the feedback, Steve. It is good to know that someone is reading all this and findingsomething hereto be useful!

To answer your questions:

1) I picked up the formica sheet at Lowes, back near the kitchen refinishing area. It comes in 4' x 8' sheets in many various colors. It is a little pricey, but to me it is the best material I have found, so far,to use as cutting templates (either for cloth or for balsa parts). When I take a sharp corner, or just stray into the template as I tend to do sometmes, I'll cut pieces clean off that are made from paper, plastic, or cardboard. Even with plywood I tend toshave the edges from time to time. This has the effect of changing the shape of the template gradually. But, of course the effects are cumulative and will eventuallyruin all the time spent in making accurate templates. The formica is much more durable and more resistant to those occasional "boo-boos". Because the 4' x 8' sheets are a little awkward for me to store and handle, until they've been cut down, now you have me wondering if cabinet shops, kitchen refinishers, or similar businesses might sell scrap cheaply (or even give it away)? If someone out there knows a cheaper source, please let us know.

2) I thinned the epoxy with denatured alcohol, and merely thinned it until it "looked right". I was going for it to bethe consistency of thePVA, beings the PVA flows together so smoothly, and I was hoping for the same effect. If I had to guess, it wasless than a thirdalcohol.

3) The results spraying it on were less successful than I would have liked. If you look closely at some of the pictures where I was applying microballoons and resin to the wingfillets, you can see pitting from bubbles that I still got from the spraying application. I'm unsure if that is because I have the wrong viscosity of the thinned resin, or maybe too much air pressure. I realized after the fact, when I saw the bubbles, that I had my pressure setting rather high on my compressor. I had gotten used to the HVLP (high volume, low air pressure) gun that has a regulator on it, set for 40psi (this gun and setting isoutstanding for applyingPVA),and I was using my O-L-D, well worn and usedbasic detail gunfor the thinned epoxy. Without its own regulator, I may have needed to adjust the air pressure lower (it was somewhere between 60 and 80psi . . . oops!) I picked these guns up (for cheap)at Harbor Freight Tools.

4) I used acetone for the cleanup, but wasn't completely thrilled with the clean-up.Things still felt a little sticky. I would bet that KlassKote's epoxy reducer would make short work of it, but that stuff is alot more expensive and not asreadily available; and, as old asthe detail gunwas, I was kinda treating it as if it were expendableanyway.

As far as masking the flanges:

As you well know (but others totally new to this may not have considered), they do need to be PVA-ed because when we join the mold halves, there are places where the epoxy used at this stage will seep a little into the crack. If the flanges are unprotected, you may glue everything together well enough that the only way to separate it all will be to cause damage either to the molded part, or the molds themselves. I think your idea would probably work. The problem hereis that making these paper flange covers to fit, takes upsome ofthe additionaltime that would have beensaved by the sprayingprocess, versus just brushing it in,in the first place. I still think that for us guys doing one or twofuses in our garageat a time, that brushing on the coat still representsa "best practice." If doing multiples to keep ourselves and friends in race planes season after season, then taking the time to find the correct mix of thinned resin and the correct air pressue,and to make"flange cover templates"would likely be worth the time to make for your molds.

Everybody, please note Steve's commentto "tape it to the EXTERIOR (NON-tooling part of the molds," so you don't accidentally remove the PVA from where you need it.

If we were doing large scale production, perhaps a form-fitting,drop-in prefabricated lining to protect the mold halves while spraying PVA to the flanges would be worth making, but probably not what the average hobbyist wants to deal with. Just my opinion, for what it is worth.