pith helmet
Well-known member
super work. looking forward to seeing the finished product.
1986 toyota 1 ton 4x4 build
- Thread starter Beavervalley802
- Start date
rruff
Explorer
Sound thinking for the most part, though the "skeleton" part isn't necessary. Sandwich panels need "hardpoints" only where they are subjected to very concentrated force. The best way to accomplish this is with a solid piece (of something) that replaces the foam in that spot and joins the two skins together. You can use wood, but I don't think hardwood is necessary. You can also buy fiberglass extruded angle or square tubing to keep everything "rot free". The only place I'm adding hardpoints is the 3 spots where the bottom of the camper attaches to the frame pivots.
What I did was drill a bunch of holes in the foam and fill them with epoxy. I think square tubes would have been better though... but honestly I probably didn't need anything. The foam is rated for ~150 psi. If you have 1,000 lbs of force spread evenly over a 10"x10" area that's only 10psi. So ya... overkill most likely.
Best way to keep from having a concentrated load is to... spread the load out. Instead of screwing stuff into the skins use epoxy or one of the structural adhesives (like Sikaflex) if possible. The manufacturers of foam sandwich campers will usually just glue cabinets and furniture directly to the skins with no reinforcement. I think with most bought doors can be installed without screws too, but I'm not sure about that.
Your frame is fully boxed and you've even added extra reinforcement so it should be very stiff. This is good... you can attach directly to the frame and also the cab if you wish. You could use cab mounts (rubber/urethane bushings) between the frame and camper, but I'm pretty sure you don't need them.
Yes, you can do all sorts of filleting and reinforcement with hand layup; extra layers where you think you'll need them. Will you have a cabover bed? I didn't want mine sticking out past the top of the cab, and I wanted the option to sleep crossways or fore-aft, so I made the bed platform (the bottom panel of the cabover) extend 20" behind the cab. Cabinets/storage go under it. That way it's also easy to avoid excessive stress concentration at the bottom of the cabover where it meets the rest of the camper.
Beavervalley802
Member
Awesome, thanks for the tip! Found the fiberglass square tube you mentioned, i think i'll go that route! Overkill is my middle name, and i want this thing to be as stout as possible without too much additional weight.
As far as rubber mounts - my thoughts are since its attached to the cab ( and the cab has rubber mounts), it should as well. Its easy/cheap enough to do.
Yeah, my plan is to have a cab over sleeper, 4ft deep and 6ft wide. I have some ideas to really stiffen up that section as it could see up to 350-400lbs with two adults. I do like your design, being able to sleep parallel to the truck frame, but given this is such a small camper i didnt want to sacrifice that much space.
Thanks for the input!
rruff
Explorer
It'll be plenty strong and stiff if you are using 1.5" PVC and reasonable skins, and reinforce the edges and corners. No worries there.
I built a big camper on a '84 1/2 ton 2wd >20 years ago. I used the cabover for storage. The camper was too big for that truck, though I'm sure some suspension upgrades would have helped a lot!
Beavervalley802
Member
That things pretty sweet lookin! Any idea on shell weight, and MPG?
rruff
Explorer
Just guessing ~700 lbs... plus I lost the bed. 2.7mm Luan skins, 3/4" core with 1x2s every ~16" (floor was 1.5" with 2x2s and 2x4s). Covered with fiberglass matt and poly resin +gelcoat.
MPG was in the high teens usually, and it was a handful in strong crosswinds. Engine was getting tired by that point though; low compression in one cylinder after ~220k hard miles. When I first starting living in that truck I just had a little shell and got ~30 mpg typically.
Beavervalley802
Member
Life has been flying by, and ive been busy as hell. But i have made some progress!
I sand blasted under the cab and in the engine bay. I hit it with 2 coats of epoxy primer, and then 2 coats of raptor liner for the floors. The engine bay will stay with just gray primer. Eventually the whole camper will be raptor lined gray, so i figured the primer would match.
I started to get frugal when i realized how much id already put into this thing...so the back of the cab was plated with some used rusty diamond plate. Which i instantly regretted.
I have a few more logistics to figure out before shes a driver, but so far so good! Next step is to order up my foam. Im far to ashamed of my poor drawing skills to post my sletches, but my plans call for 17 sheets of 1.5" foam.
Im still pretty set on carbon core - 169/sheet for 4lb pvc 46x96. Anyone else have a cheaper high quality foam suggestion?
I sand blasted under the cab and in the engine bay. I hit it with 2 coats of epoxy primer, and then 2 coats of raptor liner for the floors. The engine bay will stay with just gray primer. Eventually the whole camper will be raptor lined gray, so i figured the primer would match.
I started to get frugal when i realized how much id already put into this thing...so the back of the cab was plated with some used rusty diamond plate. Which i instantly regretted.
I have a few more logistics to figure out before shes a driver, but so far so good! Next step is to order up my foam. Im far to ashamed of my poor drawing skills to post my sletches, but my plans call for 17 sheets of 1.5" foam.
Im still pretty set on carbon core - 169/sheet for 4lb pvc 46x96. Anyone else have a cheaper high quality foam suggestion?
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rruff
Explorer
People in CA can't even buy XPS now, so hopefully you'll be able get what you want. Supply issues are hitting everything...
Beavervalley802
Member
Im a little nervous, but their website says in stock. Im going to call tomorrow and confirm.
ExpoMike
Well-known member
Tell me about it. Been trying to get 1.5" XPS for months in CA.
Beavervalley802
Member
I just got off the phone with someone at carbon core - they answered after hours, then acted annoyed that i called...anyways he told me it would be a week or two out if ordered tomorrow via the website. Im going to call back tomorrow during business hours to confirm.
Beavervalley802
Member
Im not sure, he was kind of quiet/mumbling, and as soon as he told me they were technically closed, i wasnt going to ask more questions.
Beavervalley802
Member
4lb 1.5" pvc foam on the way, 16 sheets. They said it would take about a week to cut, and a week to ship, so im pretty stoked about that.
NOW, i havent ordered any fiberglass yet. Im looking for suggestions on what type of cloth/matt to use. This will be getting layers both inside and out, something to consider is the outside will be coated in raptor liner, so i dont neccesarily need a perfect gloss finish. However the inside should be as smooth as possible.
Thanks!
NOW, i havent ordered any fiberglass yet. Im looking for suggestions on what type of cloth/matt to use. This will be getting layers both inside and out, something to consider is the outside will be coated in raptor liner, so i dont neccesarily need a perfect gloss finish. However the inside should be as smooth as possible.
Thanks!