Do not use black oxide in anything, ever. I used black oxide M8 bolts for the aluminum extrusions at first, and to attach the plywood. Some have began to rust after only a couple of months. Buy stainless steel everything.

If you go with aluminum extrusions, try to keep in mind the design of your overall framing system for drawers and cabinets too. My bed was a huge priority and I just wanted it done. I didn’t know what I wanted out of van garage cabinets for my electrical system and drawers at the time, and because of this I have to work around what I’ve already built from the extrusions when it could’ve been much simpler.

If I had to buy foam again, it would be only one or two inches of the gel memory foam.

Use blue Loctite threadlocker on all of the extrusion bolts. They’ll rattle out of the nut even when they’re tight.

I’ll be using flat head hex bolts in the future for wood attachment.

The main rectangle of my bed support. This section is narrow enough that it extends past the bulge of metal by the slider door and past the corners in the back of the van by the rear doors to fill the gap.

I oversized a few pieces of the aluminum extrusions to be safe and trimmed them down slightly.

The original plan was to use 3″ or 4″ wooden slats bolted into the extrusions, which would have been lighter and easier to build with more breath-ability for the mattress. After a week or two of weighing the pro’s and con’s I decided to go with plywood to support the foam completely.

Since I don’t have access to a drill press I found a drill guide with a stop that attaches to the bit. I mapped the bolt pattern for the extrusions and drilled them with a forstner bit.

Three coats of matte water based interior polyurethane, lightly sanded between each coat with 220 grit, and wet sanded the last coat with 1000 grit which was completely unnecessary.

I tried pressing a piece of wood into the foam to get a clean line with a box cutter but the foam was too dense. Moved on to scissors but the edge wasn’t even, and then tried this fine tooth saw but it made a huge mess. Foam cutters don’t work. Using a serrated knife with long consistent strokes was the best solution for the cuts.