>I'm using a hardshell on my foam construction..... can anyone give me some >pointers to look out for when hardshelling and fiberglassing? Do I hardshell >first then wait for it to dry completely or do I put my fiberglass >layup on when >its still wet? >David Swanson +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
I'll try not to repeat most of the good info already given but I don't think your question on "hardshelling" was really addressed. I will repeat one thing that Larry H. said and that is never use flox when sealing the foam. Flox is only used where you need a structural bond. You can us it to radius a corner under a glass lay up or mix it with epoxy to keep the epoxy from running on a vertical joint. Yes, you can hardshell the foam, that is letting the epoxy / micro (glass beads) used to seal the foam cure completely before glassing. My entire KR was done using that method on the foam and to me it makes the wet lay up go much easier if you are doing the glassing as a one man operation. The only purpose of a micro / epoxy mix is to fill the voids in the top surface of the foam with something lighter than the pure epoxy mix. Once the foam is sanded to shape, mix epoxy well and then add glass beads (micro) until the mix is approx the thickness of honey. Pour the mix on the foam and squeegee the mix to cover the entire surface. Remove any excess. Additional micro can be added to create a more solid mix to fill cracks or voids in the foam or any voids around the edges. Too thin a mix in these areas will run and leave a low spot or void. Try to make this sealing layer as smooth as possible without humps, etc. Your only purpose is to fill the open cells on the top surface of the foam. Allow the mix to totally cure. When cured, use some 100 or 120 grit sand paper on a block and very lightly brush the entire surface to remove any "prickles" that will snag the glass as you try to position it for the wet lay up. One or two swipes should be all that is necessary. You are now ready the do your wet lay up. Using the two step process of hardshelling is much less demanding when doing an area the size of the wing for example than trying to seal the foam and doing the wet lay up all in one process, especially when working alone. It also has the benefit of keeping any of the micro mix from leaching up in to the first layer of glass. Anyone suspect of this process should do some sample test blocks. Do one using the single step process and one using the "hardshell" method and do a peel test after they have cured. The cured glass will peel from both blocks at the bottom edge of the micro mix, whether it was done in a one or two step process. We were discussing peel ply the last couple of days and no one mentioned the use of the "deck cloth" (1.45oz glass) as a finish top layer. Do an archive search for a novel on that subject. As always, your results may vary. Larry Flesner
