I avoid expanding foam at all cost. It never stops expanding. There are many other ways to attach foam. Hot glue is one of them. Let your resin covering cure, then attach your foam.
See N64KR at http://KRBuilder.org - Then click on the pics See you in Mt. Vernon - 2006 - KR Gathering There is a time for building and a time for FLYING and the time for building is over. Daniel R. Heath - Lexington, SC -------Original Message------- An alternative to the buttering step, is to run an even bead of minimal expanding foam along the edge of the foam board and pin in place against the still wet resin.