POD: Custom camper - design stage

[pods8]

I made up some test parts that would have about the worst case curves I'd need to deal with I think. The smaller one I went ahead a quickly faired/finished (I'd take a bit more time on a final product but it was good enough to fill in the weave and seams). I was just using a squeegee and noticed it difficult to try and work some of the air bubbles out of the fabric on these parts because it would drag the fabric some and disrupt the inside corners and edge wraps. I think I'll need to pick up a laminating roller and see how well they work for working out air bubbles without dragging the fabric around.

 

[Roaming Robertsons]

I just ordered a 10# fiberglass/composite propane tank. I got the tall one since I'm more concerned about floor space than height. It'll be much lighter than the 20# steel tank to start, plus 1/2 the propane but plenty for a fairly lengthy trip (cooking only, no heater). I'll let you know what I think of it when it arrives.

It arrived and I was surprised at a few things. It's a two piece design with an overlapping seam in the middle of the tank. It has to be recertified every five years and has a life of 15. I just got back from filling it up with 2.35 gallons of propane. The guy at the propane place was rather amused at being able to see the LPG coming in, the float going up, and the straw. According to the scale, it weighs 19.2 pounds full and about 9.3 pounds empty. It is very light even when full, quite a bit less than a full jerry can. I'm very happy with it thus far.

 

[gerferd21]

Nice idea for a camper. It's obvious you've spent a lot of time on the design. The foam has now piqued my interest; it looks like it could open up a lot of possibilities in the structure. What is it exactly?
Shane

 

[pods8]

Nice idea for a camper. It's obvious you've spent a lot of time on the design. The foam has now piqued my interest; it looks like it could open up a lot of possibilities in the structure. What is it exactly?
Shane

Polystyrene foam board, both Dow and Owens Corning make it. Dow is blue and Owens Corning is pink. There are a variety of density and compression strengths made however availability can be tricky for some of the better versions. The 1" thick boards for those test pieces is Owens Corning Foamular 250 with has a 25psi compression strength. The other foamular lines are 150, 400, 600, 1000 which have 15psi, 40psi, 60psi, and 100psi compression strengths respectively. However the higher strength ones aren't readily available outside of 2" thickness. I'm not even considering the 150. I'll need to use the 250 for any 1" thick pieces in the design but for all the 2" thick stuff I'll be using the 600 (not much of a price upgrade from 250 so I'll take the extra compression strength, however to go to the 100psi stuff its a 4x increase, I'm not sure if there is some manufacturing change to justify that or just availability, either way 60psi compression strength works for the bulk areas and I'll spot reinforce as needed).

To use this foam you have to use epoxy as polyester resin will dissolve it. Its not as good as the higher density polyurethane foams but they are substantially more expensive and so far I think this will likely meet my needs. Some home built airplanes use polystyrene foam like this so with the right design features I think a camper will do just fine. I'm continuing along with test pieces to get a feel for things, comparing how hard it is to peel laminations off the foam, foam with wood strips every so often, etc.

Definitely has possibilities.

 

[teleturns]

To use this foam you have to use epoxy as polyester resin will dissolve it. Its not as good as the higher density polyurethane foams but they are substantially more expensive and so far I think this will likely meet my needs. Some home built airplanes use polystyrene foam like this so with the right design features I think a camper will do just fine. I'm continuing along with test pieces to get a feel for things, comparing how hard it is to peel laminations off the foam, foam with wood strips every so often, etc.

Definitely has possibilities.

PODS

Can you go into more detail about the epoxy and fiberglass fabric you are testing? If I missed it in a previous post I'm sorry. Thanks

I really like your design. I think the biggest upgrade from a FWC will be the side access door. After seeing your design I am considering cutting my FWC up and putting the door on the side. Storing spare tires and bicycles out of the way at the rear of the truck would be optimal for me.

Keep up the awesome work!

 

[pods8]

PODS

Can you go into more detail about the epoxy and fiberglass fabric you are testing? If I missed it in a previous post I'm sorry. Thanks

Any decent resin capable of laminating would work. However since I speculated I'd need closer to 15gal of mixed epoxy to do the camper it quickly became important to try and find a cost effective one. I'm trying out US composites 635 resin with the 4:1 hardener. Their bulk prices are pretty decent compared to others. The choice of the 4:1 is due to it being winter here right now and its usable down to 45F, with extended curing times of course.

For fabric I'm trying style 7725 which is a 8.8oz 2x2 twill and style 7781 which is a 8.95oz 8 harness satin weave. One of these would make up the bulk of the camper. I'd need some uni direction fiberglass cloth along the cabover rails as well.

The airplane guys use 7725 "BID" primarily. It lays on radius well and has longer flat runs of fibers before ducking above/below the weave again. However I've found it to be a bit more delicate to work with while cutting/handling in terms of fibers getting knocked out of alingment, etc. The 7781 is a little stiffer but tends to be a little more forgiving about holding the weave in place. I'm leaning towards that right now.

 

[Greg]

Pods8

I appreciate you sharing details as you go through this project using extruded polystyrene. In a different thread you mentioned using three fiberglass layers on both sides.

http://www.goldbrand.info/index.html
This site shows a foam hard sided pop-up motorcycle trailer designed to be pulled behind a Goldwing. Photos in prototype# 2 look to be pink extruded polystyrene. Very nice looking. Unfortunately it doesn't give details on foam and fiberglass layers.

 

[ersatzknarf]

Great information !
This method has a lot of appeal.
Thanks !

 

[pods8]

Pods8

I appreciate you sharing details as you go through this project using extruded polystyrene. In a different thread you mentioned using three fiberglass layers on both sides.

I haven't fully decide on the plys yet. The test parts I made before were 2 plys, fairly impressive strength. I beat up that corner piece in a variety of ways that makes me happy with the structural strength but I want to make up a part with 3 plys of the glass I'm using and compare the "impact" results, aka smacking it with a hammer, (I'll share results later).

Right now the main body could go either way between 2 or 3 plys. I, very roughly, estimate each layer would add ~120lb so if I get notable better impact performance on 3 plys I'd likely go that route and justify the cost & weight. The inside bottom I'm likely going to have a 1/8 layer of plywood over the foam and in that case I'd definitely only do 2 plys.

Various areas may get spot reinforcement as I look at them more. The cabover rails definitely will have multiple unidirectional fiberglass layers across the top. That is really the main critical calculation of the whole camper in my mind.


Lots of other little details to work out as well such as lift design, jack brackets/tie downs, final pop up style, door design, etc. Most things that interface with the walls generally need to be figured out before I could charge forward on an actual build.

 

[Heifer Boy]

Lots of other little details to work out as well such as lift design, jack brackets/tie downs, final pop up style, door design, etc. Most things that interface with the walls generally need to be figured out before I could charge forward on an actual build.

Looking good pods8.

How are you actually going to attach things to the walls? I assume you would have a renforcement plate on the other side as the foam won't have any strength itself. How is it on compression if you bolt something though it like that?

Have you seen this build up http://www.hookedupfilms.com/huf-adventure-vehicle/ . Similar construction concept to yours.

 

[pods8]

Looking good pods8.

How are you actually going to attach things to the walls? I assume you would have a renforcement plate on the other side as the foam won't have any strength itself. How is it on compression if you bolt something though it like that?

Have you seen this build up http://www.hookedupfilms.com/huf-adventure-vehicle/ . Similar construction concept to yours.

A combination of embedded wood where screwing is required and glued/fillets joints (just like your box) where I don't think I'll need to remove something again.

The 2" foam I'll be using is 60psi compression and the 1" is 25psi, anywhere I plan to bolt something though I'll add wood blocking (either solid or a plywood box). Anything that arises after the fact that might require more support than just the foam you can drill the hole, then ream the foam out some and then inject thickened epoxy in there to beef it up.

This is mainly why I want to have as much planned out as possible before embarking.


Yes I've been chatting back and forth with him on his build and we've been sharing ideas.

 

[pods8]

http://www.goldbrand.info/index.html
This site shows a foam hard sided pop-up motorcycle trailer designed to be pulled behind a Goldwing. Photos in prototype# 2 look to be pink extruded polystyrene. Very nice looking. Unfortunately it doesn't give details on foam and fiberglass layers.

I just got a chance to look that over, cool build as well.

 

[pods8]

I mocked up the potential camper outline on my current truck/camper to get a true visual interpretation. The increased cab over thickness didn't appear as thick in person so that is reassuring there is room to play with.

I also mocked up part of the interior layout to again get an in person spacial interpretation. It was a little tighter than I would have thought but since I'm planning to have a lot of flexibility in the table it really doesn't have to be as snug all the time, esp. when the table is completely removed. Right now I'm thinking a 25/50/25 table split (or something of that nature) that is on slides to more around when in place. Mocking it up definitely confirmed the extra counter space over the fridge will be needed. I'll probably build a thin cabinet over over that and have the fridge pullout on slides. It'll narrow off the door during that time put will provide an working space to set things on while loading/unloading the fridge. The driver side bench will be ~48" wide and that works for 2 adults if needed. The passenger side will be 40" which would be a little snug for 2 adults. Both would work well for an adult and kid which is what I'm designing for.

No to try and make a final decision about a single or dual pop up and figure out window placement, door design, etc.

 

[Heifer Boy]

I love a good bit of CAD design (Cardboard Aided Design). It makes such a difference being able to see it properly. Looking good.

 

[Overland Hadley]

I love a good bit of CAD design (Cardboard Aided Design).

:ylsmoke: