Hi, I've done a lot of reading on this site and was initially very excited about building a "Foamie" truck camper. After getting some supplies and building some samples, I was less enthused. The PMF construction has a lot going for it but it isn't very strong or resistant to denting and punctures. I made some samples with 10 oz canvas and TB2 and compared it to one with 2.7mm cheap luan skins. Foamular 150 15 psi foam in both. The luan was a lot harder to penetrate with screwdriver (~2x?). But it was also about twice as heavy, which gave me hope for PMF. I built a truck camper about 16 years ago using foam and luan sandwich with layer of fiberglass cloth, polyester resin, and gelcoat on the outside. That was really solid! Could a foam and PMF camper be just as durable if it weighed about the same? I understand that durability wasn't the highest priority with this method. Rather cheap, light, well insulated, won't rot, non toxic, easy to work with, and "durable enough"... but... Is there a way to step up the durability a good deal without losing too much of the Foamie's best attributes? I don't mind spending a little more or increasing the weight within reason, if I can have the rest.
The first things that come to my mind are stronger foam, heavy cloth (or multiple layers), and a stronger exterior shell than latex paint (maybe Monstaliner?). People who live up north might be able to find heavier duty foam, but I've had zero luck where I live unless I order 50 sheets. I did eventually find a place that would ship, but they wanted $600 just for shipping 18 1" sheets! It basically cost as much as the foam itself, and the foam wasn't cheap either! The good stuff is Foamular 600 or High Load 60, both are extruded 60 psi styrofoam. The common hardware store foam is 15 or 25 psi. Comparison chart: http://www.foamular.com/assets/0/144/17 ... 5bea18.pdf Seems like using foam that can take over 2-4x the pressure before it deforms would be a good idea. If you can get it. I've heard that concrete contractors will often sell it if you live in a cold climate.
So now I'm looking at the PMF layer. It seems to be a pretty good composite. I like that it uses natural fibers and the "resin" is very non toxic. It's strong for its weight. But I don't see many people doubling or tripling the layers like they do with fiberglass. Is it just because one layer is enough? It isn't for me! Or are there issues with multiple layers? I have some double layer samples drying, but I'd like to know what others experiences have been.
Thank you!