Truck camper questions and ideas

[Williamrf]

So I have been wanting to build a pop up truck camper similar to fwc project M for a while, basically a pop up truck camper on the bedrails with no tub. my plans are to use 2x2 framing, 1.5 inch foam, to skin the interior/exterior with 1/5 inch ply, cover with 3 layers of 6oz fiberglass cloth polyester resin, and then to paint with topside paint. I'm looking for advice or ideas on the build. Is the camper going to be strong enough with the 2x2 minimal framing and 1/5 ply with 3 layers of glass? Should I use a router and round over bit on all the corners and fill with Bondo, wood filler? Or just use fiberglass tape on corners before covering with additional layers of glass?

[tony.latham]

I'll answer the one question I'm confident about.

Should I use a router and round over bit on all the corners and fill with Bondo, wood filler?

It'll be a lot easier to glass the corners if they are rounded. Nearly impossible if they are at 90º. Or at least a bear. And since the corner is supported by a 1.5" frame, why Bondo? The round-over bit will create a uniform radius.

Why polyester resin? I switched to epoxy years ago and won't go back.

Tony

[Williamrf]

I'll answer the one question I'm confident about.

Should I use a router and round over bit on all the corners and fill with Bondo, wood filler?

It'll be a lot easier to glass the corners if they are rounded. Nearly impossible if they are at 90º. Or at least a bear. And since the corner is supported by a 1.5" frame, why Bondo? The round-over bit will create a uniform radius.

Why polyester resin? I switched to epoxy years ago and won't go back.

Tony

I figured if I did a round over bit and used some Bondo/wood filler and sanded it would come out better, but I was unsure if it would be necessary. I was going to use poly resin based on research I've done, it's said to be easier for those inexperienced in fiberglass and cheaper.

[RJ Howell]

I have some reads for you. First this one I'm looking at to do for a friend next spring. We are discussing a couple changes from his design, yet minor changes. Ha, everyone does this..

https://www.tacomaworld.com/threads/how-to-diy-wedge-camper.604686/

This one is currently being built. It's frame up, yet same principles involved.

https://expeditionportal.com/forum/threads/diy-composite-camper-t100-expedition-vehicle-build.225362/

My build is in this forum.

https://www.tnttt.com/viewtopic.php?f=55&t=72408

Each of us traveled a different build path, yet all have merit. I went steel frame, Ripcord went aluminum and Matt is creating a SIP with plywood and poured foam. My experience in wood framing is the structural components have to be fairly substantial to carry the load over the cab (loft). Even with plywood skins (IS & OS) there's weight to be considered.

Tell ya, if 80/20 prices were better, I'd say frame with that and do XPS/FG panels to infill. My buddy is watching the prices as he approaches his build. I've done hatches with the XPS/FG system and experimented with FRP & Corrugated plastic panels as skins. Still testing to decide which way to go, I just know no plywood..

Another here that is or will be building is dbhosttexas.

Folks here are great to bounce ideas off of, so don't hesitate! Looking forward to hearing more of the build!

[twisted lines]

I have some reads for you.

Good stuff!
From a old fisherman, that likes to drag a boat around Back when I use to could

[tony.latham]

I was going to use poly resin based on research I've done...

Epoxy may be easier because of the mixing ratios. I always thought the process of measuring catalyst for polyester resin was a pain. Once resin –-be it epoxy or polyester–- is mixed, they both spread the same.









Tony

[KCStudly]

2 plys (layers) of 6oz will be enough, especially over plywood.

I did 2 plys directly over foam, and it is good for puncture and dent resistance, and adds plenty of strength.

I agree with Tony, use epoxy. It is more expensive, and you have to be diligent about your mix ratios, but it is a much better product IMO. Stays somewhat flexible and is less prone to cracking.

A small digital gram scale and a cheat sheet for batch sizes solves 99.9% of the mix errors. I use clear plastic cups to mix in (repurposed Dunkin Donuts iced coffee cups) and prefer them to solo or paper mixing cups. You can see the contents directly and can get a better idea that you are mixing completely. I keep a wrist watch with second hand in my work area and always time my mixing to the recommended 2 min mark (for West System). I use a paper plate zeroed out on the scale to catch any drips or spills (when using the hand pumps away from the scale there really aren't any), and on that paper plate I have my most commonly used ratios written boldly in sharpie. I converted the cheat list to resin weight then total weight of resin and hardener, that way I can pump my desired resin amount, check it on the scale (I usually have to add just a touch, like .5 gram... which is the resolution of my scale... to get it exact compared to equivalent pump strokes), then add the same number of hardener strokes and check for final weight on the scale without having to do any math. I usually have to add a tiny bit more of the hardener, too, to make it exact. I'm sure the pumps would be close enough, so long as you count right, but having the scale is a good check that you have gotten the correct number of pumps, and lets me get the ratio exact. In my whole build I only had two batches not cure properly. One was too small of a batch for the resolution of my scale, so the consequences were also small. The other was a small patch area that didn't layout right. I think I may have reused a mixing cup and the batch started to gel too soon; I was able to pull that layup off before it got too firm, and redo it the next day.

Prior to my build I had very limited experience doing composites. Looked at videos of home built aircraft and cedar canoes, and talked to a friend with experience. I started with my tongue box (a smaller project) to gain confidence.

With 6oz I found the smallest radius I could wrap w/o concern of lifting (and thus creating air pockets) was about 5/16 inch. Perhaps a little less, 1/4 inch, if laid on the diagonal. I had no problems at all wrapping the 3/4 inch radius between walls and roof, so my suggestion is to use the largest radius that suits your design appearance.

If you want a tighter corner/edge, like at your door jambs, you can use what is called a flocked (or flox) corner. It is a bit more involved, but it lets you keep a sharp corner w/o leaving any sub-material exposed.

Here's a spot in my build where I started using some of those techniques.

The method I used on my hatch edges (laminating the underside seal lip, then back gouging for the flox before laminating the side edge... which you can see the result of at the beginning of this post) was tedious. I used an improved method on my door openings and door edges which you can see about half way down this post.

[dbhosttexas]

That's what I am doing, very slowly but basically...

2x2 nominal (1.5x1.5), with 2 layers 3/4" foam, and PMF. But at that point the build diverges. I am making the camper wider than the truck bed rails, and spanning the bed east / west accross the bed raisl, such that it folds up to a sofa with no overcab. Kitchen is limited to a table under the awning, and bath is a Joolca Ensuite Double. Hot water heater / shower unit will be onboard to the camper though. A Camplux 5L with a 12V pump.

You have LOTS of options, but in my case. I am opting for the primary structure / skeleton of the frame to be mortise and tenon joinery, all outer corners will be gone over with a 1/2" roundover bit. (Working on my M&T technique now...)

Most likely will end up doing diagonal torsional bracing , no metal fasteners here either, hardwood dowels and glue.

1/5 ply? Not going to add much structurally.

It sounds like you are looking for a way to skin and separate polyester resin from foam. Why not use epoxy foam and glass straight to the foam on both sides?. Lay the glass smooth, then you can worry about filling gaps, pinholes etc... with filler although resin migh tbe a better idea.

I am assuming you are building for a half ton truck trying to keep weight down.

Consider IF you are going to build cabinetry, keep it removable, and consider foam construction there as well...