Build - Fiberglass & Foam Truck Camper

rruff

Explorer
rruff how is your new camper going? Mine is in the same state but I have a new direction I am going with it.
Kevin

Stalled. I only have the base and one side done, and the other side half done. Barely started really. My wife had to sell her business and do some other things in support of that, so we won't be full timing for a couple years. So I decided to focus on racing bikes before my final "retirement".
 

The Artisan

Adventurer
Stalled. I only have the base and one side done, and the other side half done. Barely started really. My wife had to sell her business and do some other things in support of that, so we won't be full timing for a couple years. So I decided to focus on racing bikes before my final "retirement".
That's cool, so a few yrs you will retire?
Kevin
 

blinkerfluid

New member
Thanks for posting all this info; really appreciate it!

Oddly I built nearly the identical sample with XPS using the same Foamular. I had to jump up and "kung **** stomp" it to get it to break. The foam is indeed weak and very light (1.55 lb/ft^3 vs 5 lb for Divinycell) and will be the first thing to fail. I'd usually get a diagonal crack through the foam and then part of one side of the FG would break away from the foam.

But still I deemed it suitable for my use, which is a full size camper that is frame mounted. I believe it will survive the stresses it will encounter, and it's much less expensive. A look online shows 1in sheets of Divinycell are $324, plus I would have had to pay considerable shipping. Price with shipping would be ~$13/ft^2 vs $1/ft^2 for the 2" Foamular 250 I'm using. My full cost of materials for the epoxy, cloth and foam for the panels is <$6/ft^2. I couldn't justify using high priced foam.

I'm definitely not dissing your choices at all! I know... I tend to go the cheap route first and see if that works for me ;) Many people go for "the best" right off the bat and run with it.

The XPS foam does need to be properly prepped. Light sanding first and then clean the surface. I tried using a wallpaper perforator and carpet roller to texture the foam, but the thing that seems to work best is a dog brush (recommend by someone on ExPo). It creates a lot of vertical slices.

I also have every sheet of foam edged with a piece of wood, for my piece of mind and to give the panel additional strength, particualrly at the corners and edges.

Hi all, I'm Underkill's husband.. figured I could make a few posts as well to answer some questions/etc.

We really did consider using XPS pretty seriously for a proof of concept build, mostly because of the cost and how light the stuff is (our primary goal was to save as much weight as possible). The strength of the XPS foam really wasn't what turned us off of it though; we knew we could use thicker foam to strengthen the panel, but once we saw how easy it was to peel the fiberglass from the foam we decided we didn't want to go through all the effort of building the camper only to worry about delamination issues. In the end though, we were able to find a local composite supply shop that had everything in stock, so we didn't have to worry about trying to order the divinycell foam and getting it deliverd (usually by truck freight); that made the choice easier for us. For sure it was not the cheap route by any means, and we did have some reservations spending so much money having never done any composite work before. After a couple minor mistakes early on though, everything went pretty smoothly. We ended up using 8 sheets of 1/2" foam for our build, but I can't remember off the top of my head how much each sheet cost. Definitley an order of magnitude more expensive than XPS.

We actaully did different types of prep for multiple test panels; you can see from the photo I posted above, the foam has holes in it from a wallpaper perforator. We sanded and cleaned each panel prior to layup, but found no significant difference in the strength of each panel, or how easy it was to peel the skin off. We didn't try the dog brush idea though, that does seem like it might increase surface area a fair amount; although bonding issues weren't the problem we encountered.
 

rruff

Explorer
...once we saw how easy it was to peel the fiberglass from the foam we decided we didn't want to go through all the effort of building the camper only to worry about delamination issues.

Interesting. When I did delam testing there were larger pieces of XPS that came away, in keeping with the perforations. I wouldn't say it took a ton of force to pull the skin off, but considering the concentrated load I was putting on it I thought it was sufficient, since high forces pulling the skin off wouldn't happen in practice. Plus I have wood every 4ft or less and the FG is stuck very well to that.

The strength sample I made was 36" long, 6" wide and 2" thick. I could support that on the ends and jump up and down on it and it was fine (170lb) . I had to really land with a stomp it to get it to fail.

There are expedition camper panel makers who use XPS cores. Not real high density foam either.

What was the epoxy you used and the temperature? Just wondering if that would make a difference.
 

blinkerfluid

New member
Interesting. When I did delam testing there were larger pieces of XPS that came away, in keeping with the perforations. I wouldn't say it took a ton of force to pull the skin off, but considering the concentrated load I was putting on it I thought it was sufficient, since high forces pulling the skin off wouldn't happen in practice. Plus I have wood every 4ft or less and the FG is stuck very well to that.

The strength sample I made was 36" long, 6" wide and 2" thick. I could support that on the ends and jump up and down on it and it was fine (170lb) . I had to really land with a stomp it to get it to fail.

There are expedition camper panel makers who use XPS cores. Not real high density foam either.

What was the epoxy you used and the temperature? Just wondering if that would make a difference.

I think my biggest concern with delamination would be with impact damage.. I was worried about something like a bird strike denting the foam and starting the delam process. For our test piece, it seemed like it took a fair amount of effort to start delaminating the panel, but once it started it was relatively easy to peel the skin off.

We were using West Systems epoxy with 206 hardener and temps in the low 70s.

Are you using wood as a framing material?

Please don't think I'm trying to talk you out of using XPS, the cost savings alone makes it worth considering; and using wood in your build along with the foam will certainly add some extra strength. It sounds like you had better luck with your test panels than we had with ours.
 

rruff

Explorer
Are you using wood as a framing material?

It would be more accurate to say all the foam is edged with wood. So all the edges of the camper are wood, plus at least every 4'.

It would take a lot more than a bird strike to cause a problem I think, considering how hard I have to hit it with a hammer to see any effect. My first test piece is 2'x8'x2" with wood around the edges. I can support that on the ends and jump up and down on it with impunity. Very stiff and strong.

On the base (floor) I used two layers of 1708 on each side, plus there is a lot more wood in the floor. The sides and back are 2 layers of 1700 exterior, and 1700 +6oz interior. The front and roof will be 2x 1708 on the outside.

You were using good epoxy and it should have been plenty thin to penetrate your texturing. I'm a little concerned is all, since I obviously can't destruction test my final build! I'll just have to use it and see what happens.

Thanks for the info, it's very helpful!
 

underkill

Active member
Ok I'm back now! :) I believe I left off where we started framing in the walls to make an actual tub. The forward part of the camper was designed so that the "floor" or base of the cabover bed part was only a few inches above the roof of the truck. Luckily I could do this as one piece. The aft bulkhead of the camper had to be taller, so we were forced to do it in two pieces.
IMG_9458.jpg

Previously we had only been laying up glass on one side of each panel, but this time we decided that we might as well do both sides before starting to assemble. It's much much easier to roll fiberglass and resin onto a flat surface than it is on a vertical one. Here are the panels drying in the sun in the back of the truck while we went to get lunch.
IMG_9477.jpg

Since the gorilla glue takes 24 hours to cure it's really the limiting factor in how quickly we can assemble the camper. We decided to go ahead and put in both walls with the additional triangle radius pieces all at once so it only had to cure a single time. I ended up having to shove the toothpicks into the foam at an angle, but it ended up working really well. The foam only needs enough force holding it down to counteract the pressure of the foamy glue as it expands. I went through a lot of toothpicks.
IMG_9479.jpg

Here's the entire thing drying in the shed with a tie down strap for good measure!
IMG_9480.jpg

The hot summer sun shines directly into the storage shed after about 10 in the morning, so the glue was dry enough to move around in a few hours! We, of course, had to do a test fit in the back of the truck!
IMG_9481.jpg

It's super low profile, just like we wanted!
IMG_9482.jpg
 

underkill

Active member
Any reason why not to expand the width to fit around the fender wells?
i'm assuming you mean at the back right? We were originally going to do that and make little storage lockers like a lot of the other campers have, but since we made the inside tub pretty much the entire width of the bed between the wells, there wasn't really a lot of room left. We thought about mounting some rotopax gas cans in that spot instead just never ended up doing it. In hindsight we should have narrowed the camper a little bit on the inside. We ended up with some wasted space inside the camper, but it worked out in the end.
 

underkill

Active member
After sanding off the excess foaming glue and rounding the gusset pieces into a nice concave shape, we glassed in the corners all around.
IMG_9486.jpg

IMG_9487.jpg

We did finally figure out what how long it is before the resin starts to set up. Apparently it turns into an annoying jelly-like substance that doesn't stick to anything. I'm sure the heat in the afternoon doesn't help!
Now it's time to flip this thing over and start the fiberglass on the other side. This isn't the weirdest thing we've had in our backyard. The neighbors haven't noticed it yet. ;)
IMG_9491.jpg

Here's a detail of the radius that I sanded on all of the sharp corners. The glass bends around that easily. Also note the fiberglass repair that we did after getting air bubbles where the radius was too sharp. Lesson learned there. The foam sands just as easily as it cuts, so I've been using a sanding block and sandpaper. It's easy enough to do by hand.
IMG_9490.jpg
 

underkill

Active member
So at this point, the camper is starting to turn into a pain in the ass. We still have to be able to move around, but it doesn't sit flat anymore, so we made some spacers with wood scraps.
IMG_9492.jpg

Since the back part of the bedsides aren't supported, we clamped them to a piece of steel to try to keep everything as square as possible while we glassed in the bottom part.
IMG_9493.jpg

and here's the second half of the back bulkhead all cut and ready to glass!
IMG_9494.jpg

Our plan for the bottom of the tub was to do it in a single sheet of glass and wrap around the corners. After cutting the huge sheet we marked the corners so it would be easier to put it in the right spot when we laid it down over the wet epoxy. On that note, we did find it was easier to saturate the fiberglass if we put the resin down first and laid glass on top of it.
IMG_9495.jpg

While we were doing fiberglass anyway, we went ahead and did one side of the bulkhead so we only had to waste gloves and brushes one time.
IMG_9497.jpg
 

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