by KCStudly » Tue Jan 19, 2016 12:05 am
Yes. I did this on my build. I used a variation of Steve Fredrick's method. The 1-1/2 inch thk foam wall cores were built with a 2x2 cedar sill and door frame surround, then I routed out pockets for 1x pine blocking everywhere a screw would need to go; cabinet face frame ends, bulkhead wall, light switch mounting plates, side mounted dome lights, coat hooks, pillow lights, etc. Those were all glued and weighted in place with GG, GS and sometimes TB2, depending on fit and my experimental mood; all were successful, and almost all of them needed work to clean up and fair.
The inner 5mm ply was laminated to the foam and vacuum bagged with a makeshift shop vac bag setup.
At the wall top I added some more pine blocks for the spars to screw down into, but first I glued all of the spars to the top of the ceiling skin and finished the underside of the ceiling before installing it. The ceiling was glued on top of the walls... IIRC I used PLP... and the spars were screwed down into the blocking. The joint line on the inside of the walls and ceiling is tight and I did not need any trim. Note that my cabinet face frames are a structural part of "The Box". They act like trusses and add to the rigidity of the wall tops. Also, the ceiling skin was glued and screwed all across the front and rear cabinet top rails. Then I infilled the space between spars with the roof foam. On the outside, I held the ceiling panel back from the outside face of the wall about 1/2 inch to help bury the plywood and keep it away from any possibility of moisture intrusion thru the edge. I "chinked" the gap between the top of the wall foam and the roof foam (the thickness of the ceiling ply) by cutting strips of foam and wedging them into the gap. I think I used TB2 for this, but it may have been PL300. Can't recall at the moment.
The profile of the roof was rounded over to a 3/4 inch radius and I am now in the process of preparing the cabin for a wrap in 2 plies of 6oz fiberglass cloth and epoxy. My original plan was to use PMF with cotton canvas, and I still think that would have worked very well. I just got to the point with my build where I had so much time and money invested, it just made sense to me to go all the way. Either way, the strength comes from the unity of the complete structure, which is all tied together with the outer skin, whether it is canvas and glue, or epoxy and FG. My cabin is as rigid as it could be; when I lift, push or pull on any part of it, nothing moves or everything moves as one single part. If I pick up on one corner there is absolutely no twist; and the outer skin isn't even on yet, and the cabin it isn't even mounted to the trailer yet.
Don't be afraid to experiment with the different glues and such. I have tried most of the commonly used ones throughout my build and they each have advantages and disadvantages in different situations.
Follow this advice and you can't screw up so badly that it won't work out in the end: (1) Design as a complete structure (each part does not need to hold the whole camper up, they all work together to be stronger than the individual parts). (2) Build light through out; the weight and the strength will add up and will both be there in the end when you need it. (3) Make tight accurate joints and glue well; sloppy joints are weak. (4) Seal out moisture from the weather, and make provisions for venting out moisture from the occupants.
KC
My Build:
The Poet Creek Express Hybrid Foamie
Poet Creek Or Bust
Engineering the TLAR way - "That Looks About Right"
TnTTT ORIGINAL 200A LANTERN CLUB = "The 200A Gang"Green Lantern Corpsmen
