I don’t know, but from my limited knowledge of composites, I can say that the epoxy/resin is much less important to the overall properties and performance of a composite structure than the reinforcing fiber - both type, amount, and orientation/layout.
As long as the epoxy/resin is “good enough”, then the rest is up to the fibers. Any of the name brands will do. West system, Pro-set, Raka, Masterbond, 3M, they will all work.
Probably the more important thing is to make sure the epoxy is the right viscosity for your planned application method (vacuum infusion needs a much thinner, runnier resin than hand layup for example), and it has enough pot life.
I’m pretty sure they have a secret sauce. You just won’t get a layup as flexible as their decks with the systems I’m aware of. They are definitely using something out of the ordinary, like flexible roofing epoxy, or some other off use product. Their boards are 15 to 17 layers of what appears to be a heavy roving. If you were to use a traditional epoxy system with that many layers, it would be as stiff as a proverbial board. Whatever they are using is so soft, you can almost dig your fingernails into it.
edit: I have found flexible epoxy systems, but they are prohibitively expensive, and obviously, Trampa isn’t going to use something that’s isn’t economical. Most epoxies are formulated to be as stiff as possible.
I have a limited understanding of polyester resin, but from what I do understand, it’s much less flexible than epoxy. I’m currently looking into additives that claim to reduce the shore hardness of epoxy.
Maybe they are using urethane with a low shore hardness. That’s kind of what the feeling of their decks reminds me of. Whatever it is, it’s not obvious.
Maybe vinylester?
(Edit) why does it matter so much. Composite performance properties consist of much more than the resin type (hence the fact that they are called composite). Fabric type, weight, strength, laying direction, post curing methods etc all come into play on a part like a skateboard deck.
It’s about the only thing stopping me from attempting to make a deck. I’d also like to try make flexible battery enclosures. Well, a combination of stiff and flexible. Though, I need a real workshop more than anything. That is my biggest hurdle. I’ll just work outside if I have to.
I think it would be easier to just use a less-stiff fiber such as fiberglass or kevlar, than trying to find a magic resin.
Different fiber orientations also really affect things a LOT.
But it is stiff in composites.
+/-
Narrow Stringers of UD carbon in an otherwise FG layup can add significant stiffness to those parts, perhaps without fully enclosing any radio gear. There’s a lot of possibilities.
By now I think people know that CF can cause radio issues.
New folks stumble in every day and folks could be reading this years from now, and I think in devices where your life can depend on radio reception, not constantly repeating this could be a safety risk. A major downside to be considered about carbon is almost never mentioned yet it needs to be known by everyone using it.
Folks who haven’t done this before may not know that. I’d like to prevent injuries before they happen, not after
Deck shape can also have a huge impact on stiffness (same as for enclosures - and any structure really). Trampa decks seem to be flat sheets with minimal concave. When you add concave and gas pedals etc. you increase structural depth of the board and it can be stiffer because of this depth (think about segmented enclosures)
But it is stiff in composites.
