ccxnola wrote:
Tom,
I agree that is what we have been told by the RV makers, but...is it because it is easier and cheaper to do it that way?? I know there are many very good fibrelass boat hulls that take a beating in the ocean - and they are one-piece hulls, not a bunch of panels stuck together. Is there an engineer among us for some enlightenment??
If your roof front and rear caps were layed up as a single laminate and co cured together you would not have a problem. For example if the laminate was 1/4 thick like a boat hull the individual layers of fiber glass an resin would be over lapped by at least 1/2 in and the overlaps would be staggered. When cured their strength would be as if they were one continuous layer of fiber glass and resin. Resin has very little strength other than to stiffen the fiber glass cloth so it can carry the load. Also polyester and epoxy resin have very little elongation before it fails. It is brittle. You would be covering the the seams with resin any movement of the joints caused by vibrations going down the road would have to go right through the resin over lap. I would feel safer with an elastomeric material like Eternabond over the joints. Just picture a 1/4 thick fiberglass laminate 12 ins by 1 in and try to flex it. It will flex forever with out cracking. Now picture the same laminate with a 1/2 over lap in the middle joining the two pieces together the same amount of flexing will cause a failure in the resin bond line. Hope this helps.
