I was wondering if it is possible to make a 23’ x 4’ surfboard that is going to be used as a store prop? I know I could piece together a couple of polystene blanks to make something of that magnitude, but that would require epoxy resin. What would be the way to glue the pieces together (angle cuts, staggering, ect.)Is it possible to find a 23’ blank in polyurethane? What would be more cost efficient a) glued polystrene blanks with epoxy or b) polyurethane blank with polyester resin. The board can be any shape (short, long…) but it has to have a fin and resemble a surfboard. Anyone have ideas on how to complete this?
If it’s just a prop, it doesn’t have to have ANYTHING related to “normal” surfboard construction. Hell, it could be solid wood, cast iron, whatever. Just because it wants to LOOK like a surfboard doesn’t mean it will be constructed like one.
Still, lightness is desirable in something that big, and I’d suggest a styrofoam core, sealed and covered with floor finish (usually single-component polyurethane these days) or whatever kind of paint will give you the necessary gloss. Heck, why gloss? Something that big isn’t likely intended for close inspection.
Free your mind - this is not a surfboard, just an object, a store prop. Unless you think you’re gonna have a quick paddle-out before you deliver… 
All true…
Cheapest and easiest prolly styro sheets from HomeDepot/Lowes/Yardbirds/hardware stores, paint seal with latex housepaint 3 times, then glass the middle of the board (the flats, don’t bother to wrap the rails) with couple layers of 6oz and poly resin.
If you want it to look ‘true’ and be theoretically functional, get in touch with Mike Eaton. eatonsurf.com He builds paddleboards out of EPS blanks and epoxy glass up to 22’ long, and built a uh um boat (?) out of the same stuff, about 25’ x 6’ wide, built & shaped like a surfboard and then outfitted with a motor mount, tractor seats on the deck, and a little whaler-style console. Thing’s a riot. Sits in one of his parking spots in front of the shop. I know he gets his foam in 16’ x 2’ x 2’ blanks and glues them together to make the longer ones. His foam supplier is in LA and he’s in San Diego. He runs a nice bulletin board on his website where you might get some easy info. Some of the other paddleboard guys - Bark, Pang - check in from time to time as well. Hope that helps…
The Ron Jon’s in Ship Bottom NJ has a board that is billed as the world’s largest surfboard, and is close to the dimensions that your looking for. Why not contact them and get some info as to who built it and how.
“and built a uh um boat (?) out of the same stuff, about 25’ x 6’ wide”
Jim Foley of Santa Cruz, an artist/innovator/fireman/hot surfer who was surfing waaay ahead of his time in the mid-60’s, built a 33 foot sailboat (his third or fourth design) out of (as I heard it) sheets of surfboard foam in the late 70’s/early 80’s. It was named “Third Reef” and was exceptionally fast - so fast that Hobie copied it and called it the Hobie 33.
2 or 3 of these cut in half along their length should give you the foam you need.
[img]How should i connect the pieces of Polystrene from Lowes together? I will need a little bit longer than 2 10’ pieces. The board will be flat and have no rocker, (it is used as a prop) so what kind of glue will give me the best bond? How should i glue the pieces of foam together? I provided a few examples in the awesome paintbrush attachment. Another question I have is what kind of paint will I have to use when covering the eps with polyester resin? Should I only do one coat of paint so the resin will bond?
Just dowel them with 1" dowel, or make a foam biscuit. If you use several of the 2’ sheets just stagger the joints length and width wise. Glue should be latex based. You might also check home depot for their elastomeric roof coating and fabric to cover the thing.
I have been using Elmer’s on EPS from Home Depot. I know there is some concern that, without air circulating, the glue won’t set up right. Trust me, the glue is fine. I use the 2" thick sheets and pour out the glue on both pieces, roll it smooth with a stiff foam paint roller, slap them together, and put a bunch of heavy stuff on top. You need to wait a couple days. But later, when I cut my board outline, cut the stringer in, shape off the excess, etc., the glue is cured through & through. I always take the scraps and try to break them along the glue line, just to see. Every single time, I get foam failures about 1/4" inch away from the glue line, but NEVER a separation of the glue.
You need a 23’ x 4’ board. I would get 6 sheets of 4’x8’x2" foam. Cut one of them in half to make 2 4’x4’ pieces. Just lay 3 full sheets end-to-end on the ground and paint them with Elmer’s. Paint the 2 other full sheets and the 2 halfs of the cut sheet. Slap them together, starting with the half sheets so your joints are staggered by 4’. Put 3 sheets of plywood on top and pile a whole bunch of heavy stuff on top of that. A few kid’s wading pools filled with water would be cheap, easy, and very heavy.
2 or 3 days later, unpile the whole thing and cut in a stringer. You probably want the stringer to look proportional to the board, so I’d use 6 8’ pieces of KD redwood or cedar 1x6. Stagger the joints & glue just like you did the foam, by cutting one in half first. You’ll end up with a 1.5" wide stringer that looks great under the glass and provides the stiffness you need when shaping & glassing.
Don’f forget to post photos!
Another glue method might be LEXEL aulk/glue. Comes in a caulk tube at HD. We use it to glue stone caps on stone retainng walls. A quater size dollup every square foot and a perimeter / middle bead would do you.
Benny has the best stagger method. But look for the elstomeric stuff with the fabric. it will look like volon cloth when u are done.
theres a 26ftish longboard in newquay,england,poly foam blank and poly resin/glass/fabric print…ill ask about it next time im in town.
i might even be able to get a pic
oh,and its been surfed a few times.
wow what a great problem this is great …‘’… how thick? man o man this is cool…go you guys…ambrose…wow!