Foamie cabinetry and bed platform?

[SpitballJedi]

I'm just spitballing here. I'm trying to keep weight to a minimum in my truck bed camper and am considering making the cabinets and bed platform with foam.

I know xps has great compression strength, but what about when it's vertical? If it's standing on edge, would it support a bed platform? Maybe make a frame with vertical supports using wood and 1" foam to fill it in, then PMF the whole thing using bed sheets or something light-weight. The foam would then be 1" thick and lighter than 3/4" ply.

Also, what about the platform? Do you think a 30" wide 1" xps with PMF would be okay for a sleeping platform? Maybe 1/8" luan on both sides and then PMF? Or, a few 1x4 supports? Maybe by the time I do all that, I've done a lot more work to save very little weight.

I can't seem to find anyone who has experience using foam this way.

[Pmullen503]

For a bed platform, foam sandwiched with plywood will definitely work. The only question is how thick the foam needs to be. That will depend on how its supported; legs at the corners, one whole side attached to a wall, etc.

You can buy 250lb sq ft compressive strength foam but do you really want to give up the floor space it would take to make foam legs?

Bottow line, it will be lighter, but more work to build.

Cabinetry has been done with foam and PMF or fiberglass. Sometimes just the carcass with nice wooden doors.

[rjgimp]

You can absolutely make light and strong cabinetry and built in furniture out of foam. I did some looking on youtube some time ago and found a couple different guys doing such things with great success. One guy was building out an old VW van. He constructed a base cabinet of 1" foam skinned with (I think) 1/8" plywood. He actually set the completed unit on the ground and stood on top of it and jumped up and down on it to demonstrate its strength. He was no Andre the Giant or John Candy but a normal looking guy, maybe 5'9" or 5'10" and 170ish pounds or so. Certainly if you are then going to also attach the thing to the camper walls I don't see any problem with building a bed in the same way. You could build a structure of intersecting vertical panels under the mattress. The bed platform could be on a hinge with support rods to expose a bunch of 2' x 2' storage areas underneath. This is in fact what I am planning for my build. I'll see if I can find the video.

[SpitballJedi]

I've seen the video with the VW guy. Hos cabinets have relatively small spans though. Imgoing to pock up some boards tonight to experiment with. Im sure I'll need verti al supports, especially in the midsection.

[twisted lines]

I have seen the videos long ago, I have done a larger span and it’s only crazy after you put the second side on
My dog’s raised bed in the back. (Lab) not the little

[ghcoe]

I have not done it, but I believe that if you use 2" foam you could make a sleeping platform. I would support it with 2" foam around the parameter and then run a piece of 2" down the middle. If you have a mattress, I don't think you would have to even PMF it unless you wanted to. I would not try this with 1" though. Your only adding 3.5 pounds per sheet for 2", but it is only 1/3 more on cost usually.

[dbhosttexas]

I guess I didn't scroll down far enough to catch this post. I am trying to do the same thing. My thought process is...

#1. 1" XPS sandwiched between 1/8" plywood for panels inserted into a 1.25x1.25 (2x2 planed down) frame with braces every 16 inches or so. Will need to work that number out. I need to enclose the side on the inside the truck bed, and the end. The outside I am going to rely on the actual outer wall of the truck bed to enclose it.
#2. The actual horizontal support for the bed will need to be 3/4" ply. I can't afford to eat up height as the mattress is a 6" memory foam residential twin size mattress so 38x78.
#3. The Ford truck beds curve up to the sides instead of making a radical 90. I will likely need to end the frame, and the sleeper panel a few inches shy of the outer wall, WIll likely use a piano hinge to make all that work. I want divided compartments so foamie to the rescue there as well...

So if anyone has tested this out, let us know your results. I know I for one am anxious to get that part of my build started.

[RJ Howell]

The over cab portion of my truck camper (the loft) is my sleeping area. I have a perimeter and a single (run up the middle) of 1.5 x 1.5 .125 steel tube as the frame. 1.5 XPS sandwiched by fiberglass and 5/8" ply over. I'm 6-1 @ 240lbs and I can see deflection in the foam. Nothing is breaking or not supporting, just I should have more support.

In your case of building in a truck bed (floor under the entire platform), I would certainly have intermediate support (storage bays) and a sheet of ply over. With intermediate supports I'd believe 3/8" ply would suffice. Typical in a truck bed is the full slide out tray to excess from the back.. I think you'll need to rethink that as a short rear slide so you can have intermediate supports (bays to excess from the side).

Hope some of this helps! Safe Travels!

[twisted lines]

My dog’s bed failed!
Cheaper version caulk; price of Burch ply,
Hope it was the Resin I disliked doing fiberglass.

[jakejakejake]

Hey Jedi! I build with foam and Fiberglass so my comment here are based off of that.

I have no reservations about the vertical portion of the bed platform. In that axis the foam is acting much like the web of a beam. Instead of bending the 1" foam your trying to bend the full depth of material (however tall the platform is) The proposed 30" span for the horizontal portion is also easily achieved. The roof of my build is something like a 70" span and I could tap-dance in the middle with zero deflection.


As the core thickness increases the relative stiffness increases exponentially

here's a good read on foam core composite strength
https://explorecomposites.com/articles/ ... tructures/

As others have pointed out its a significant amount of labor to save just a few pounds. For that reason I went with 1/2 ply for my bed platform. Building it is fun, but I actually want to camp out of it some day!