Hi RM. You will like it, if I do say so myself
The main wing and controll surface material is all 6mm Depron. Guys have used blue fan fold sucessfully but its not as stiff as the Depron so you may want to scale down a bit.
You could probably use the foam poster board, but I have never tried that stuff so I dont know how strong it is in comparison to Depron.
Hinge tape is 3M Blenderm medical tape. Other tapes wil work, but nothing beets Blenderm.
The sponsons are made from 2" thick pink building insulation board. I get mine from Home Depot in 2' wide x 8' long sheets for about $20 or so IIRC. Its enough to build a few dozen sets of sponsons
If you find a broken sheet they will often sell it to you way cheeper or even give it to you. Regular lumber yards often carry the pink foam as well.
I have also used pool toy "Noodle board" foam for the sponsons. It has the advantage of being similar to EPP foam in that it bends and springs back after a crash. The down side is that is a pain to work with as far as getting glues to stick and it only comes in ugly colors
I think white EPS might work but it would be more fragile.
One of the guys in the club is planning to try pipe insulation foam tubes on his sponsons. Havent seen that yet so dont know how well its going to work.
I cover the bottoms of my sponsons with plastic cut from large jugs of cat littler. I glue it on with 3M 77 spray adhesive. It lasts forever and is very slick. Works better on grass and snow than duct tape, tho Duct tape will work and is cheep and easy. It wears out fast on pavement but is easy to replace.
Others have had good luck with the thin baking sheets from Target. I think they are made from teflon or something similar. Very slick and reasonably tough but a little pricey. I forget what they were using to glue them on with.
For glue on the main wing joints - Gorilla brand glue or any similar expanding Polyurethane type glue will work best by far. I like the Sumo brand because its white and looks the best. It has the worst bottles tho. Very tough to squeeze. I have used CA and epoxy but they seem to be more brittle and the joints have broken easier.
I usually use foam safe CA on the motor mount and to glue in the rudder but the PU or epoxy will work as well.
Ofcourse, CorrosionX is the best at water proofing.
Thats about it I think