RE: Sig Somethin Extra idea??
After thinking about this post for awhile. I have come to the conclusion.
If you use contest grade balsa, maybe at the most an extra one ounce per wing panel.
Depending on what you use to cover it will or will not break you. I have used .55 oz. Fiberglass from CST on my pattern planes.
Couple of steps i use.
1 Sand the sheeting smooth vacuum it off.
2 Put one coat of Balsarite for film over all the wing sheeting. It stinks bad but it seals the wood so the epoxy will not soak into the sheeting and add a ton of weight.
3 Use either the .55 oz. fiberglass or the 3/4oz. fiberglass. Put this on with Zap finishing epoxy or i have used Great Planes finishing and Bob Smith Finish cure as well. I add about 10% of acetone to the mixture. If you add to much acetone it will get real gummy and not want to dry for about a month.
4 using a paint brush not a acid brush but a nice soft paint brush. about 3/4 of a inch wide works for me allthough i have used a 1/2 wide one as well. Put a light coat over the fiberglass as light as you can. Be stingy with the resin.
5 While the Resin is wet in other words right after you are done putting it on. put Micro balloons over the surface and work them into the resin by hand. I use a bare hand for this not a glove. This is to fill the weave without anymore resin. as you rub this in. You will feel the Micro balloons being absorbed by the resin until all you feel is the Micro balloons not any resin at all.
6 Repeat with the other panel
7 using a sanding block sand the excess fiberglass overlap off the trailing edge and the leading edge of both wing panels
8 Repeat steps 1 thru 7 for the other halves.
9 Sand everything trying your best not to cut into the fiberglass cloth. If you do cut into the glass use a little bit of CA and rub it in with your finger with a small piece of wax paper. All the while marveling at how easy it is to sand with the Micro balloons in it.
10 Stand back and amaze yourself on how little weight is in it. Maybe another one ounce per wing panel.
11 Whatever primer you decide to use the thinner the coat needed for coverage the better. Paint adds zero strength only adds weight. Steps 1 and 9 are the important steps. Skip on the sanding and your primer coat will be trying to fill all kinds of voids, grooves and other ugly things.
12 I would be shocked if you add 6 ounces over the stock wings with Monokote. You can make some of that up with either Hites HS-225 or Tower Hobbies TS 35 Servos Might save you a 1/2 ounce per servo.