Ice-box corner filet material under epoxy & glass…what to use..?

[paularey]

I am just getting ready to finish the final assembly of a rather large built in ice-box under the cockpit seating area of my catamaran and I was wondering what might work best for filleting/adding a small radius to the corners before laying some fiberglass tape to the seems with epoxy resin…? Brief description my ice-box is approximately 24 inches deep by 24 inches wide by 34 inches across. And is made out of 4 inch thick Styrofoam panels with a thin but solid layer of woven fiberglass & chopped strand matt combination bonded to one side with epoxy resin. I fitted the pieces (foam only) in place then removed them individually and glassed the interior portions while horizontal in my shop. The panels turned out really nice. Now I just want to install them into the ice-box frame and seal all the corners with a narrow stripe of fiberglass tape but I would like to lay a small radius of some kind of filler/fairing compound in the corners before doing so. I was going to us a polyurethane chalking but I thought it might be better to have a solid material to back up the glass. I am in Panama so my resources are limited. Is there anything wrong with using bondo or a similar material? I only plan on laying in a small radius so the tape will transition the corners smoothly. I am a novice with composites so any input is appreciated. I would like to avoid something that can absorb water and lower my ice-box efficiency.

Thanks

[gonzo]

If this is just for waterproofing, bondo will work fine. After it cures, sand it and dewax it for better adhesion.

[John ilett]

You should just make some filler for the fillet, sand when dry and lay your tapes on top. Use the same resin for the fillet with a suitable filler, maybe Q cells, micro balloons or similar.