Im shaping a board for the first time using eps foam from Home Depot, I have the rocker all formed, for a stringer surfersteve recomends a glue joint out of great stuff spray foam instead of a traditional bass wood as it would be less complicated and shapes easy im worried about the strength? any body ever tried this?
most homemade EPS foam blanks that ive seen used 1/4" (roughly) plywood. So for a board less than 8 feet in length, you can just cut a 4"-6" (depends on rocker + blank thickness) strip of plywood out of an 8 foot sheet. Its easy enough to shape a plywood stringer. Believe me making a board out of Home Depot foam, the last thing you need to worry about is planing down a wooden stringer - it'l be easy.
I've never used Great Stuff, but I have used divinycell, which is a rigid, high density PVC foam. I'm guessing the Great Stuff recommendation is going to be about the same thing. You can buy sheets divinycell at the Depot, but... I've found it's not as strong, and much more flexible than wood. All it does is help hold the rocker. All your strength is going to have to come from your skins. I've used 1/8 ply, 1/16 ply, basswood, redwood, cedar, and fiberglass. For ease of shaping, foam is the easiest, fiberglass the second easiest (just simply laminate a couple layers of 4 oz. between the halves), followed by basswood, redwood and cedar. Ply is harder to shape because you have to deal with the end grain, but all of these materials shape just fine if you use sharp tools. Personally, I go for strength and the right flex characteristics over ease of shaping, which, for me, means wood.
dude , dont do it sure you can save a few bucks by going the home-depot route but you will save yourself a ton of time and energy if you just order a close tolerance blank . Shaping ends up getting ex*****ve when you have to buy everything to start, I know until I started shaping i didnt just have a power planer ,surform or block plane or shaping racks laying around the house why spend all the money on the tools just to use some cheap foam , and if money is tight just acquire the tools over time if you stick with it shaping can be a life long hobby dont just look short term
shy away from great stuff if possible, I've used it working and would never use it for this application. really this is a no brainer, use wood... you've already got some cheap foam so you may as well quit cutting corners at that point.
