I’m looking at shaping a long board. I have a friend who works for a company that does foam sculpting they use regular styrofoam and then hard coat it with a product called ChemThane from Chem-Line. As an artical I found about the product: “The EPS is coated with Chemthane 7000, a spray applied polyurethane hard coating that adds rigidity and structural stability to the foam. The coating is applied at 3/16” (5mm) thick. Over the top of the primed polyurethane is applied a Venetian stucco and a UV resistant top coat to protect the finish from the harsh Florida sun and chlorinated water.” (link: http://www.landscapeonline.com/research/article/5101) Now my Questions are:
I was wondering if anybody has tried to build a board with the polyurethane spray?
Seems like it is a very strong coating, would you think I would need to lay glass on it or, just straight shoot it?
Seems if it can sprayed on, it doesn’t provide enough structural rigidity for a long surfboard. If it can, it might be too brittle and crack. Are you gonna use stringers in the blank?
Even Bics poly construction has what appears to be one layer of actual glass to stiffen the structure.
You can always buy some, apply it with a brush in the appropriate thickness, then bend it. Obviously, on a piece of scrap foam…
It sounds like the Chemthane 7000 is a structural material. While this may work well for a surfboard monument in a park, however I think it would be tooo heavy and stiff to have much value in either sealing or improving a surfboard. I guess it would be weather tight! This combination of materials is often used for architectural structures, and lends itself very well for the purpose for which it was intended.
Yea, alot of that is the same I was thinking. My friend who works with the stuff thinks its gonna be strong enough. He also said they have differnt kinds of ChemThane with varying amounts of flex. I was gonna try to go stringerless, but am rethinking that to add strength. I guess the upside of all this will it will be free to build. What I have been thinking is going with a thin coat of the polyu and then glass over it, Think I should use Poly or Epoxy?
I’ve seen the stuff. Originally developed to coat EPS for floatation applications. Too flexible and somewhat heavy for boards. Lots of folks have dreamed of a coating that you could just spray on the blank and then go surf. But without a fiber in the resin there is no spring to the exterior plastic coating. We just did some testing on a new plastic for coatings. A thermoplastic which could be glued onto the blank and with some heat formed over the rails. Highly touted stuff. So we did side by sides against epoxy/fiberglass and the stuff fell so short it wasn’t even close. At double the weight it was still too flexible. Glassing will still be your best bet for the forseeable future. Stiffness per weight, FRP still rules.