Fiberglass Composite Camper Construction?

[Nitromethane43]

I have been thinking about building a truck camper for a while, after looking it seems that a fiberglass composite construction would be a good choice for my plans. After reading about the Super Camper built by Tacodoc, using Niacore panels, I was really interested in going for a composite construction over wood or metal.This is going to be for a 3/4 ton long bed pickup, keeping the exterior walls within the truck's footprint instead of the wide campers offered in the commercial market.

What do you guys think about building a slide in style truck camper using fiberglass foam sandwich construction. The main structure would be assembled with 1.5" or 2" extruded foam panels then covered with glass mat on either side to create a monolithic sandwich structure. There some concerns over the structural integrity of the cab over part, there is really no way of adding strength without taking up interior space. The maximum weight in there would only be about 400-450lbs with two people, a foam mattress, and solar panels on the roof, personally I do not see a problem with the structure holding that weight but I am not a structural engineer either.

Let me know what you guys think and any comments, suggestions, or tips would be appreciated.




Here is a picture of the exterior, the interior layout is still being worked out.

[theMec]

If this is a one-off, ie. for your use only, I'd design it for a flatbed. Then the sides can come straight down and you'll have much more space.

[spencyg]

Yeah....loose the bed completely and build a sweet flat bed. You'll be able to tuck more storage in boxes bolted in front of the rear wheels below the bed, and your camper will be much more spacious.
I wouldn't use glass mat on anything in your camper. Its only purpose is rigidity/stiffness, and needs to be used in conjunction with a bi-weave cloth. Mat can typically only be used with polyester resins which will eat right through your foam cores. Get yourself a 5 gal setup of West System and some good marine grade glass cloth. Stay away from anything sold at a car parts store...this is all going to be marine grade stuff.

You have a few options for epoxy:

West System (best support)
MAS (claims to be non-allergenic)
System 3 (stay away from 3:1 mixture, you only want 5:1)

If it was me and I was doing a composite structure, I wouldn't use metal at all. I'd do a very nice glued wood frame to support the foam. You could incorporate a few bonded metal plates where tie-down points will be. The majority of the strength will come from your foam core and fiberglass substrate. Using this building method, you can build a very strong and light assembly which will also be very insulated from both sound and temperature.

I have thought many times about building this sort of camper on a Dodge 3/4 ton platform (with the Cummins of course). If a cab pass-thru was incorporated it would be a very economical and proficient package...

Spence

[Lynn]

WRT to the 'go with a flatbed' comments, I disagree.

I assume you what it to be demountable, since you've designed a slide-in. The difficulty with a demountable on a flatbed is that you still can't get heavy items like water tanks down low without plumbing and stuff penetrating the flatbed. Then it's not demountable. And a flatbed raises the entire camper above the wheels (rather than sitting down between them like a slide-in), raising the CG significantly.

If you don't need it to be demountable, the flatbed is just extra weight, and I would go with a chassis mount.

If this is a one-off, ie. for your use only, I'd design it for a flatbed. Then the sides can come straight down and you'll have much more space.

With access doors on the inside, the area between the camper base and the pickup bed sidewalls is good for storage.

[Nitromethane43]

Thanks for the comments they are greatly appreciated.

The flat bed or chassis idea would be great, right now I do not have permanent plans for the vehicle, as it is only a regular cab and the additional space of a crew cab would be preferred. So the vehicle may be changed out at a later date , plus it is easier to sell down the road. Once a solid vehicle is found they I would love to make a chassis camper for it, this one would be more of an experiment to see what works and what doesn't since one will always see improvements once it starts getting used.

spencyg, you did bring bring up a good point about the glass, I was thinking about spraying it with the chop gun for speed, cloth seems to be a better choice for strength. Yes, it is a Cummins under the hood, along with a 60 gallon wvo tank, which needs to be relocated.

[Lynn]

I'm curious about your design of the lower walls.

I assume that the double stepped lower sidewalls (one step to clear the sidewalls and another step to clear the wheel wells) are to maximize interior volume? The area above the step in the wall is usually occupied by cabinets or a dinette, so I don't think you have much to gain with the double step.

Where you can gain valuable interior space is the area behind the wheel well. Only the area in front of, and adjacent to, the wheel wells needs to clear the wheel wells, so it can be wider behind the wheel wells. That will gain quite a bit of usable interior space in the back of the camper.



My father built a few slide-in campers, and that space directly behind one of the wheel wells is a good place for a toilet room, if you want one.

Here's a floor plan that shows the toilet room behind the wheel well.





Actually, if it were me, I would do something like this:



On the passenger side rear would be the toilet room, and on the driver's side rear would be a propane/gear locker accessible from the outside. But, of course, I would have to add access doors so that I could use that space in front of the wheel wells for storage, as well.

The above images were borrowed from Glen-Ls cab-over camper plans site. It might interest you to look through their plans, construction photos, customer's projects, etc. if you haven't already.

[Nitromethane43]

Lynn, thanks for the suggestion, you are right about the 2 feet or so behind the wheel wells, squaring it our adds quite a bit of space. I am looking into the Thetford cassette toilet C-400, with will change the design to a squared out corner for an access hatch on the back side. The double step holds a 20 gallon tank on each side along with room for 4 batteries.

Your father built quite a nice camper, I bet he has a lot of pride in it. How much wider are the extensions beyond the truck bed?

All the comments have truly been invaluable in helping the camper design progress, it's all very well appreciated.

[Grim Reaper]

If this is a one-off, ie. for your use only, I'd design it for a flatbed. Then the sides can come straight down and you'll have much more space.

To design for a flat bed you have to make it taller in relation to the ground. The only gain in the flat bed design is it makes it easier to build and a small 6-8 inches where the bed rail would have been. The flat bed rides higher on the chassis to clear the wheel wells. A properly designed slide in will have a lower CG and lower overall height if it is a all hard side construction with no pop up type of feature.

To maximize space and minimize weight design for a changeable platform so that you would load the camper onto a mostly bare frame with saddle boxes that stay on the truck in front of the wheels. Then make a flat bed platform that can be installed when camper is not in use.

[Lynn]

=Your father built quite a nice camper, I bet he has a lot of pride in it. .

In the intreset of giving where credit is due, all the pix I posted I gleaned from the GlenL site. I don't have any pix of the campers my father built.

Having said that, yes, they were quite nice! He was trying to build them professionally, but couldn't find buyers willing to pay for the quality. In total he only built 4 or 5 slide-ins and one chassis-mount. This was back in the '70s. The chassis mount was built for my grandfather in '72, and has recently passed to my nephew, whose working with my dad to get it fixed up and on the road again.

How much wider are the extensions beyond the truck bed?

He wasn't interested in building trail-capable rigs, so all his went out to the full legal limit, which I think used to be 8' wide, and now is 8'3".

[theMec]

The difficulty with a demountable on a flatbed is that you still can't get heavy items like water tanks down low without plumbing and stuff penetrating the flatbed. Then it's not demountable. And a flatbed raises the entire camper above the wheels (rather than sitting down between them like a slide-in), raising the CG significantly.

Seems like the Aussie's don't have any problems w/ demountable flatbed designs. I think w/ the underbody boxes and water systems under the flatbed, the CG might be lower than a slide-in design. Depends on a number of factors.

I'll have to spend some time calc'ing the space savings. Maybe it's not worth it but for my Dodge the exterior measurement is 80" and the inside interior measurement between the top of the bed rails is 62". That's quite a difference ..

The obvious disadvantage of a flatbed build is that you have to be committed. Harder to sell later w/o a normal bed and the daughter won't want to drive it around town when she learns to drive.