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.

 

[boblynch]

I'm struggling with the same thing (ease of resale vs. maximum storage/functionality).

In your case the choice seems to be based on the future of the truck. If you want to do a trial camper, mated to a truck you might sell or have your daughter drive, then stick to a standard size slide-in camper. You can still swap the standard bed for a flatbed and boxes (above and below the flatbed). When you're ready, sell the slide-in camper, flatbed and boxes, and then reinstall the original bed. All of this modularity might be more trouble than it’s worth.

The Aussies have two big advantages. First, they have a market where flatbeds are common, so resale is easier and components are readily available. Second, it’s warm. They can mount water tanks below the frame and outside of the camper box without them freezing.

If you want a long-term one-off camper that can be moved from truck to truck, I’d only consider a flatbed or chassis-mount design. In this scenario I’d stick to industry standard frame rail specs and cab-to-axle dimensions.

Good luck.

Bob

 

[Slough the Grid]

Sandwich Core Material?

Just wondering if you ever built your camper? I'm in the process of designing my own and am currently struggling over the issue of what type of foam core to use. Does anyone have any suggestions on a foam core material that would be light, yet thick (at least 2") and strong enough to maintain structural integrity. Price is of course an issue. I would love to use one of the popular cores designed for marine use, but they all seem to be very thin (I want to have the R value that a thicker material will provide) and quite expensive (I found 48" by 48" , 5/8"thick stock selling for $145.00 a sheet). I probably don't require the resistance of a speedboat hull but I don't want it to fall apart on the highway either. I probably will be using the MAS epoxy products as they seem to be less poisonous than some of the others out there.
Thank you and your responders for this thread, as it has thus far helped me out a great deal in researching this issue.

Cheers

 

[whatcharterboat]

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.

Is this true? Could someone please enlighten me on this? I just find this a bit foreign and can't imagine why. Here it is actually the opposite. Most carpenters, plumbers, tilers and virtually all other tradesman who makeup the majority of utility/ute (or pickup) sales won't consider anything but a flatbed (trayback) with dropsides and if it has a "normal"bed fitted, it doesn't usually last too long before it's ditched or turned into a trailer. However "normal" beds tend to far more widespread on the back of twincabs here, I've noticed.

Unless it's more of image thing like this new GM Holden ute.

Nitromethane43 > That CAD drawing looks pretty slick. So many options as far as construction methods go. Urethane foam and Polyester or Polystyrene foam with epoxy? Check out the costs involved either way. If you are going to cover it both sides with glass then you will also have to do a fair bit of bogging and fairing on the outside as well and then it will have to be painted or flowcoated if you use polyester resin. The external joins and corners can of course be done at the same time as you are glassing the sides so it ends up quite structurally sound. Forget using a chopper gun here. A woven or bi-directional cloth will be much easier to keep neat and a uniform thickness.

If you go this way, I'd be glassing the inside of the sheets before you tack them together and then just tag the corners after. Save a lot of work. I presume you already have some experience and skill with composite construction or you wouldn't have access to a chopper gun, heh?

Another option is to make a shiny table to use as a mold and you then go gelcoat> glass >foam > glass to make your own panels which will have a nice finish on the outside and chopstrand cloth is OK for this. The trick then is to work out how you are going to join them. A lot of guys simply tack the sheets together, glass all the internal corners and glue or rivet an aluminum frame around the outside. We've made stainless steel large radius external corners before that the sheets butted up to instead of going over the outside. Very cool looking and neat but probably getting a bit involved for a home builder without a long bed folder and guillotine.

BTW Use rivets that are specially designed for use into fiberglass. Do not use normal rivets.

As for fitting solar to a composite roof, look at Canon Photovoltaic Laminates (PVL's). Wierd sizes but perfect for this application and around the same price as most aluminum framed panels are anyway. Also don't forget about how you are going to line the interior or how you are going to run your electrical wiring.

Go and have a look at how foam sandwich yacht builders do it to get some construction ideas. Good luck with it.

Have a look at this caravan we built from pre-fabbed fiberglass/foam panel. Hey, notice the flatbed towing it, too. Haha.

http://www.expeditionportal.com/forum/showthread.php?t=18131

 

[ersatzknarf]

Looks like someone has started another Nida-Core camper : http://customtruckcamper.blogspot.com/

 

[laidback]

Looks like someone has started another Nida-Core camper : http://customtruckcamper.blogspot.com/

I wonder if the material he's using is strong enough to support people sleeping in the overcab bed?