Roger (K8RI) wrote:
Both the ribs and bulkheads shown above are very
fragile until bonded into place and this foam is much stronger than
the blue Styrofoam (TM) Follow the instructions on what ever you are
building and good luck.


If you're using the blue stryrofoam, rough it up good with sandpaper
before priming it. It comes with a very smooth finish from the factory,
and there's nothing for the epoxy to grab hold of. It holds much better
if you sand off all the shiny until the surface has the texture of good
suede leather.

If you're building a smaller part that needs just a little more
stiffness, try getting a bundle of the fan folded 1/4" foam. It will
split down the middle and has a paper like film between the front and
back halves. Get it to splitting in the corner and you can slide your
hand through it in karate chop fashion to split them apart. Hold one
half up to the light, and you'll notice hundreds of pinholes. Keep the
expoxy/micro mix thin, and it will run through the holes. When you do
your layup, the two sides will be locked together with hundreds of epoxy
pins going through the foam.

I did some tests of a sample of this vs straight layups of various
thickness and compositions. Overall, the 1/8" foam sample came out at
only 60% of the weight and 50% stiffer. Trying to tear it apart around
a headlight portal, where I needed to remove the foam layer, had me
convinced that this was solid stuff (I also got to create a few new
words...but children might be reading). You won't be able to do it with
out a pair of pliers.