A bed is an essential part of any camper van. But there's a myriad of options to choose for bed positioning and layout - fixed, murphy, convertible, and more. I covered these options back when I talked about planning - my choice of bed is a sliding bed, which I've now framed out.
I chose to make the bed frame, and all the van's interior framing, out of extruded aluminium (often called 8020 after the leading brand of it in the USA). This is a system of long aluminium bars with "T slots" on either side, that you can slide brackets and other fittings into and then tighten them down in the slot.
They're often used in industrial settings for making machinery stands or structures, and they have quite a few advantages over wood:
- Much stronger for the same cross-section, and for the same weight
- Easy to reposition components or adjust things after the fact
- Re-useable over and over provided you have long enough pieces
- Bend as a failure mode rather than snapping
The main reason you wouldn't choose them, honestly, is cost - the bed was probably over $2000 of aluminium extrusion bars and brackets alone, not to mention the rest of the van. It's not easy to find cheap - even my local industrial supply store was expensive, so in the end I bought a lot of it from McMaster-Carr, as their prices for it are not terrible shipping for 6 bars together ends up being quite reasonable. Can you find it elsewhere? Probably, but not much cheaper in my experience, and you'll be waiting a lot longer for delivery.
The bed's sliding mechanism is quite simple - there's a fixed part and a moving part, and the moving part has slats that interleave into the fixed section (the video makes this much clearer as you can see it). Rails run the full potential length of the bed for the sliding section to move along, and under the sliding area is room for two chairs and a slide-out dining table.
All the sliding components move against UMHW plastic components - it's a very slippery plastic that is a good fit for this, and avoids the need for bearings, wheels or metal-on-metal connections. The centre parts of the bed slide on small inserts that are part of the rail (I cut up a long strip for this), and the side parts use individual pads from the larger linear bearings, since the full bearing itself was too bulky for my design.
The bed has to support quite a large load - two people, plus mattress, potentially focused away from any of the edges. To this end, there's a few key design principles:
- The main cross-beams of the bed are 3"x1.5" double-sized extrusions, as they have significantly more weight bearing ability than the single 1.5" square bars
- All connections between components that bear load have something physically sitting on another, rather than relying on t-nuts and bolts
- The one place I wasn't able to have things sitting on each other, I used horizontal plates that still don't rely on a t-nut not slipping in its slot
- The whole structure is self-supporting onto the van floor with eight legs, rather than relying on the van's sheet metal to bear weight
While it is self-supporting in weight terms, the bed is still fastened to two long single-slot rails that I attached along the van on both sides - this is the anchor point for all of my framing, and while it's not taking any real weight load, it is helping to stop it slide around laterally.
Those side rails are fastened into the van's sheet metal using rivnuts (also called plusnuts) - little inserts that give you a much better purchase on sheet metal than using sheet metal screws, and without the risk of rust you get by exposing the raw metal when you screw into it. These are all along the van at about knee height for the main rails, and then also at head height (with the smaller 10-series, or 1", aluminium) and on the ceiling to support the upper storage cupboards.
I also made things more complicated for myself by avoiding having any supports in the "garage" area under the fixed part of the bed - adding some supports there would really help take weight off the cross beams, though it would of course limit the size of the cargo you can store under there.
I'm happy with the way the bed turned out - it slides pretty well after a few tweaks, seems capable of taking the weight of two people, and the extruded aluminium framing has been a pleasure to work with. I've also already got the seats under the bed framed out, and I've started on the shower and kitchen areas too (pausing only when I run out and have to order more, honestly).
It's also part of my principle of having a "maintainable" van - I want a van I can iterate and improve over time as I discover how I'm using it, what I'm missing, and what I don't actually need. Adjusting or moving parts around is a lot easier than it would be using wood, and I plan to use that to my advantage on the first few test trips.