Scorpion Racing

Hi Toby, I am not an expert, but here are my experiences.

For 424, I began using 1/16" sheeting (top & bottom), 1/2" x 48" .007 carbon strip spar (top & bottom), 1# density white foam cores, 1/2" wide .007 carbon strip for the trailing edge (for a straight sanding line), a 3/8"x1/2" Balsa leading edge and finished with 1/2oz. cloth.

I tried this lay up with a variety of adhesives.
ZAP laminating resin - good strength and weight - tends to yellow with time in the sunlight.
West Systems 105-206 - good strength & slightly stiffer with no yellowing - short working time and the heat of the cure would melt the foam some.
Gorilla glue - the bond and weight was good - wing was flexible and the glue sanding dust is toxic.
MGS 285 - excellent bond, super stiff and clear as day - have to buy in gallon sizes.

I have used weights on the shucks to cure as well as vacuum bagging. The vacuum bagging is by far the best way. More psi, equal pressure and not near as much space needed. My final lay up for 424 is this:

1/16" balsa skin
MGS resin
1/2" x 48" .007 carbon strip spar and 2" 1.4oz glass trailing edge strip
MGS resin over reinforcements
Foam core
MGS resin
1/2" x 48" .007 carbon strip spar and 2" 1.4oz glass trailing edge strip
MGS resin over reinforcements
1/16" balsa skin

Finish by adding the leading edge, shaping the trailing edge and cover with 1/2oz cloth and MGS resin. This method allows me to shape the trailing edge to a sharp point (better than the carbon strip) and is even stiffer.

I am testing my wings for 428 now, and have added two layers of 1.4 oz. cloth (top & Bottom) in the center section with the carbon and trailing edge reinforcements. We will see how that works out!

Hope this helps you some.