Its been a year now since I put down the glue gun and picked up the Foam Tac bottle. I've built over 20 planes for myself and others, the latest being our FRCFoamies de Havilland Mosquito:
I had such success with it that Eric from Beacon Adhesive suggested Jay and I sell it on our website. See the above link.
Many guys use it for hinges, but I use it on my whole plane, including servo placement and motor mounts, for several reasons:
1) Foam Tac makes an extremely strong bond with all foams including Depron, MPF, Dollar Tree, blue and pink stuff. A bond strength between hot glue and epoxy.
2)Foam Tac becomes tacky in about 30 seconds. Unlike hot glue, it gives you a few seconds to re position pieces before the hold is permanent. It cures in a fraction of the time of epoxy so that pinning is unnecessary. At most, I scotch tape a piece temporarily.
3)Foam tac dries to 30% of its wet weight. The plane actually gets lighter as the glue cures! On a typical parkjet I save 2-3 oz by using Foam Tac in place of Hot Glue.
4)Spreading Foam tac across a hinge creates a strong and light hinge joint within 60 seconds. NO MORE TAPE!
5)Unbreakable reinforcement! Using Foam Tac with fiberglass wall board tape creates the strongest, lightest joint or leading edge reinforcement possible. Bryce Graves has an excellent thread and video on this:
7) quick clean up! Rub your fingers together and it rolls off. And no more burnt finger tips!
8) Less is more. One bottle can build up to 3 planes when used properly!
Why do I care about a light weight, strong glue? This is the main advantage for me: LOW WING LOADING! Saving 2-3 ounces amounts to a 20% savings in weight on some planes. A 20% lower wing loading can increase performance more than doubling the thrust of your power system! Saving 2 oz in build weight allows you to use a smaller power system, which itself can save you even more weight. An example:
Building a Mig 29 v3 from RCPowers with Hot glue results in a 20 oz. plane requiring a 3s power set up. By using Foam Tac, I was able to build it at 14 oz and use a 2s power set up with unlimited performance. That's a 50% lower wing loading than with the Hot Glue plane! And the ultra low wing loading is addicting!
If you've used Foam Tac, let me know what you think. If not, get some today!