jaka

Hi!
The best method is to use either 24 hour epoxy or polyester resin. I mostly prefer polyester resin as it is much easier to mix than 24 hour epoxy that often has odd mixing quantities like 38/100. Mixing polyester resin is soo easy as you just pour in some drops of of hardener in a spoonful of base resin and mix it together.
Using hobby stuff epoxy like 30min epoxy is no good as it is too thick, soft and difficult to sand, and has to be thinned with metanol ...which makes it even more sticky and hard to sand...plastic film will not adhere well to it either.

When people mention that they use Ca glue to secure glass fiber I just shudder...[:@] Can't understand why they mess with Ca glue when it is soo difficult to use together with thin 25g -50g glasfiber and so damn hard to sand compared to polyester resin or 24 hour epoxy.

It's soo easy just to lay the 25g glassfiber weave onto the wing and just pour the resin onto it...no spray glue is needed, spreading with a "Flash" or "SIG" yellow plastic spreader or just using a small brush to spread the resin. Do not use a credit card, they are too small, too hard and don't give the right "feel " compared to the "Flash" or "SIG" spreader . It is soo easy! It only takes a couple of minutes to completely cover the center section of a .40 size airplane wing.
I use 4-5 pieces of of different shaped 25g glassfiber weave on my sport .40 airplanes.
Never just use one single piece of heavy glassfiber cloth that you often see in model airplane kits...the wing will most likely brake at the outer sharp edge of the glassfiber cloth.

Regards!
Jan K
Sweden