Bed Liner as a Camper Box Construction method (spray it on Foam Insulation board)

[The Artisan]

He still needs the sips. If he builds that 3x3 box it will just be a big rubber play toy to knock around.......
At least he can turn it into a dog house when he's done
Kevin

 

[ripperj]

My comment on tensile strength was based on my idea of a normal truck camper with a Cabover and an overhang over the bed rails. The foam and LineX combo would not support such a configuration.

 

[The Artisan]

My comment on tensile strength was based on my idea of a normal truck camper with a Cabover and an overhang over the bed rails. The foam and LineX combo would not support such a configuration.

AH that's fair a small truck camper, I thought he was making small pull behind.
Kevin

 

[goatherder]

You can use blue foam board to make something pretty damn strong. The thing you need to do is this: skin it with fiberglass cloth and epoxy. You can buy twill weave E-glass cloth fairly cheap if you shop around...#7781 comes to mind...and epoxy kits off Ebay for around $50/gallon. You need low viscosity "laminating" epoxy. Mix the epoxy, apply onto the foam board with a roller, lay the cloth on top of the wet board, then roll on more epoxy until you can't see the cloth...and squeegee out all the air bubbles. Simple

Foam board with a glass-epoxy skin is wicked strong, rigid stuff. Think surfboard. You can skin the panels, then connect them together with glass/epoxy 2-ply "tapes". Wet out 2 layers of cloth between 2 sheets of plastic, then cut into strips. Peel off one side's plastic, lay the tape along the connection, squeegee it down and then peel off the outer layer of plastic.

After cure, sand any rough spots, wash with soap and water...and THEN apply your bed liner. Now you've got something.

For more info on this, google "foam epoxy construction techniques" or "Rutan aircraft construction". West System also has info on their site.

 

[DzlToy]

I believe the OP was attempting to avoid all of that ^^

It is quite a pain in the *** (labour intensive and $$$) to do that to an entire camper box, inside and out. There is even more work if you are going to integrate bulk heads, built in furniture, a wet bath space, etc. The techniques are certainly feasible in that application, it just won't be quick, easy or cheap to build a camper box that way.

 

[Silverado08]

Aint no quick and easy way to build one off camper using any material..

Easiest to me as Im a carpenter, and something Ive considered doing,,
would be to glue sip panels together and coat the whole exterior with best roof coating available..such as

http://www.epdmcoatings.com/mobile/liquid-rubber.php

Ive done my last TC using simple 1/4 inch ply on top and sides and lower part,box from 3/4 ply reinforced with 3/4 ply ribs vertical and horizontal every couple feet kinda like a boat,,.coated with Cold cure epoxy and marine enamel..
Glued rigid foam insulation all over,,inside..
Works fine but need to recoat exterior every so often,,,next time will use rubber coating above

Heres an interesting idea for some enterprising individual,,if one wanted to make many campers and or trailers,why not use hemp plastic,seems quite tough

https://youtu.be/srgE6Tzi3Lg

 

[Victorian]

Tensile strength measures pulling forces. In a camper shell, there is nothing trying to 'tear' the Line-X off your foam panels. Similarly, there are no forces trying to pull one panel away from another as you would if opening a drawer. Tensile strength is provided for the application at hand, i.e. a truck bed protectant, where sliding boxes, firewood, chains, lawn mowers, dogs, etc. will 'assault' the surface. This is simply not the environment that the side of a camper will be exposed to. You CANNOT build a box out of foam, spray it with Line-X and expect it to have the same structural properties as a properly constructed and engineered product from someone like Earthroamer or Unicat.

Make a kid's playhouse out of it if you wish, but please do not build a camper box with it. There are enough $hitty campers out there already, rotting and rattling themselves to pieces. You need a solid sealed structure that cannot hold moisture, leak air, rot, warp, etc.

I have seen the concrete wall sprayed with Line-X and shot, hit, blasted, etc. That tells you absolutely nothing about how your camper box will perform unless you are making it from cinder blocks and shooting it. There are single part and two part bed liner products and each has it's own advantages and disadvantages, so do you research on that first.

Bedliner is HEAVY as a coating, though it does seal joints well and offer abrasion resistance. Line-X can be top-coated, but it is not inherently UV stable, so now you have another product to spray over the top of your bedliner.

A cheap ($250 - $300) test:

Purchase 2" thick sheets of XPS foam and build a box using hot glue or some other non-structural method for temporarily joining the panels together. The box should be at least two or three feet square on each side. Building a Rubik's cube from foam and spraying it won't tell you much. Find someone to spray your 36" x 36" x 36" cube and proceed to beat the hell out of it; drop it off your truck bed, hit it with a baseball bat, leave it out in the 100 degree heat and freezing cold, put a blow torch to it, etc.

If you are serious about building a camper box, this is a small price to pay to validate the idea. Take video of it all and update this thread as you go. I am sure that it will make for some good reading.

Cheers

Well said.

 

[rruff]

You can use blue foam board to make something pretty damn strong. The thing you need to do is this: skin it with fiberglass cloth and epoxy. You can buy twill weave E-glass cloth fairly cheap if you shop around...#7781 comes to mind...and epoxy kits off Ebay for around $50/gallon. You need low viscosity "laminating" epoxy. Mix the epoxy, apply onto the foam board with a roller, lay the cloth on top of the wet board, then roll on more epoxy until you can't see the cloth...and squeegee out all the air bubbles. Simple

Foam board with a glass-epoxy skin is wicked strong, rigid stuff. Think surfboard. You can skin the panels, then connect them together with glass/epoxy 2-ply "tapes". Wet out 2 layers of cloth between 2 sheets of plastic, then cut into strips. Peel off one side's plastic, lay the tape along the connection, squeegee it down and then peel off the outer layer of plastic.

After cure, sand any rough spots, wash with soap and water...and THEN apply your bed liner. Now you've got something.

On my last camper I made SIPs using thin ply skins, with foam and wood stringers in the middle. Panels were then polyester fiberglassed (mat cloth) on the exterior surface. After I joined the panels together, I fiberglassed the edges. Even though I'd never fiberglassed before, and polyester is tougher to deal with than epoxy, I had no issues at all. I was surprised at how easy it was. An advantage to using polyester is that you can apply an outer later of gelcoat which is very durable and hard.

I like your idea of doing away with the outer ply skin and using epoxy. I think it would be easier in my application and also allow rounding of the corners. Bed liner would make sense as an exterior coating then (think I'd pick Monstaliner). But the issue I'm having is the inability to buy heavy duty XPS pr EPS in small quantities. If I'm relying on it structurally (no wood stringers), I doubt the 25 psi foam (which is the heaviest I can get), will be adequate. In the boating world, polystyrene foam isn't considered adequate even in heavy duty varieties, but I'm not sure why. At any rate they typically spend $300/sheet for PVC foam.

 

[rruff]

Heres an interesting idea for some enterprising individual,,if one wanted to make many campers and or trailers,why not use hemp plastic,seems quite tough

There is a sizable contingent of people making campers out of foam and canvas cloth with Titebond glue as the "resin". http://www.tnttt.com/viewforum.php?f=55&sid=faeaf96edade531a5c981918effe464c They call it "poor man's fiberglass".

I seriously considered doing that with a bed liner coating on the outside. After building some samples of the canvas and glue, I wasn't real impressed. It is cheap and it works, but I don't think it has strength and penetration resistance of fiberglass at a similar weight. And I'm not so cheap I can't afford fiberglass.

I used Snowroof coating as the exterior surface on my first camper, and it worked great, but isn't nearly as durable against abrasion as fiberglass.

Your comment about there being "no easy way to do a one off" is very true! The details are going to take a lot of the time, regardless.

 

[The Artisan]

since you are playing with coatings try titebond III with epoxy. There is a guy that does that with fabric skinned wood frames. He says he does about a 1/4 thick and it's strong. No experience just going off what he had told me. For something that will last I would pay for professional sprays unless you buy from a co like scorpion, they seem to have a nice strong product. As stated mine will be a fairly light and well built when finished.
Kevin

 

[rruff]

since you are playing with coatings try titebond III with epoxy. There is a guy that does that with fabric skinned wood frames. He says he does about a 1/4 thick and it's strong. No experience just going off what he had told me. For something that will last I would pay for professional sprays unless you buy from a co like scorpion, they seem to have a nice strong product. As stated mine will be a fairly light and well built when finished.
Kevin

Titebond with epoxy? Are you sure it isn't Titebond and canvas?

1/4" of pretty much any coating is going to be very heavy. They generally use a single layer of 10oz canvas and it's quite thin.

 

[The Artisan]

Titebond with epoxy? Are you sure it isn't Titebond and canvas?

1/4" of pretty much any coating is going to be very heavy. They generally use a single layer of 10oz canvas and it's quite thin.

Yeah it will be, my 1/8 liner will add 300lbs, I might go 1/16 have not decided yet. He skinned the camper with canvas then he used tightbond then he used floor epoxy coating, just passing on the info he told me.
Kevin

 

[rruff]

He skinned the camper with canvas then he used tightbond then he used floor epoxy coating, just passing on the info he told me.
Kevin

That makes more sense. The epoxy floor coating I've used in the past was basically tough paint. It isn't like epoxy resin.

The canvas/titebond/foam sandwich method is ideally suited to quick, simple, cheap construction. IMO. If you want strong, durable, and lightweight, epoxy and fiberglass is better. Definitely better for an expedition camper I think.

Regarding the polyurea and similar coatings, have you played with samples? It isn't the same material, but I got some samples of Monstaliner, and it tears pretty easily. I'm skeptical of any spray or roll on coating having good tensile strength unless it has long high-strength fibers in it.

But hey, give it a try and see how it works. It may be good enough for the purpose.

 

[The Artisan]

Yeah that is why i was saying at minimal use a liner like Scorpion. You need a good 2 part spray. You can even go with cartridge type systems. The poly you are referring to is more like a poly paint. I bought an used fastkote poly on my box, not what I was thinking of for $400
The liner I am using is a military spec poly not even used for bedliners.
Kevin

 

[nsbohn]

Yeah that is why i was saying at minimal use a liner like Scorpion. You need a good 2 part spray. You can even go with cartridge type systems. The poly you are referring to is more like a poly paint. I bought an used fastkote poly on my box, not what I was thinking of for $400
The liner I am using is a military spec poly not even used for bedliners.
Kevin

Whatever came of this project? I'm in the research phase of a similar idea for a truck camper myself...