Question for Greg Loehr- I live in Western Australia where it gets real hot in summer. I’ve shaped quite a few svf sailboards and found the white, heavier stuff really delammed in the heat we get during summer. The blue as you know is lighter, dents more easily, but doesn’t delam as often. I’ve used it for a few years now with decent weight results, and only some delam problems around the footstrap area. I guess the beauty of the stuff is that you don’t have to sandwich it to get a relatively good strength to weight ratio. With Thailand heavily in the picture, it’s hard to compete material and labor wise on the sandwich board market. Most of thebig guys here in W.A. have given up. Is the edros foam you write about bead styro that needs to be sandwiched or is it dense enough to handle deck pressure with say carbon reinforcing? You guys talk about 1 and 2 pound densities but that’s not in our vocabulary. The blue svf is 28kgs/cu.mtr. whereas polyurethane (highest density surfboard foam) is 45 kgs. Some of the surfboards we are doing with the second hardest polyurethane foam and polyester resin are coming out quite light butlack the styro feel. Polyurethane sailboards built the traditional way are not in the picture anymore due to insane weight even in a windy area like W.A. I doubt that we would have access to edros uless it was manufactured but construction materials type companies, but it may be worth a try. I’m already set to hotwire, etc. due to the use of svf so that is no problem. thanks, ken
I’m posting here to convey that 2 lb/ft^3 = 32.1 kg/m^3. I don’t think I’ve used edros. I think Greg said edros is EPS (beaded styro) made in a special way for strength and to close capillaries. I’ve used only 2 lb/ft^3 EPS on surfboards and it’s strong. It dents slightly under foot with warp E, but I’ve had no delams. However, foot straps would try and pull the glass up. Greg probably has some experience there.
Sailboards are a real dilema. With beaded foams they really need to be sandwiched. Seems there isn’t a real way around it that I’ve seen. Surfboards are different. They aren’t being jumped 30 feet in the air at 30 kts. The Dow foams are OK but they do have delam problems as you have stated. I was the Dow distribuor for this product years ago and never really solved the delam problem. Have you tried using Coremat? I’ve also recently seen some core material that wraps easier. I’ll see if I can get a name. Edro foam is the best quality beaded foam you can buy but again with sailboards the forces are dramatic.
There is a mfg. in Oceanside that has had 2 molds made for individual styro blanks, a 7’0" and a 9’6". They are done in a “b” bead @ 2 pounds and a pound and a half. The thinner blank lets the steam fully penetrate it and bond the beads together better than in 4 foot by ten foot billet. I had talked to Greg for quite a while sometime back about the beaded and exruded foams. The extruded boards I have done have ALL broken and or delaminated, Greg said the chemists at Dow told him it contains 10% polypropolene and we all know how well resins stick to polypropolene. The bead boards aren’t pretty, but I think they make a lighter board than the extruded and don’t suffer from the other drawbacks. I have a 9’0" on tap for a competition longboard and a 5’6" fish out of the foam, so we’ll see how it works.