Should we use 8020 or aluminium tube for our drawers and bed?

[uncompromise]

i’m looking for feedback and advice on the best materials for our setup. We have a 2004 LWB Mitusbishi Pajero (Montero/Shogun) with a 2nd and 3rd row seat delete. We are going to be using the vehicle for extended on and off road travel throughout Europe and North Africa in a variety of urban and wilderness environments. The truck is also our daily driver that we use with two adults, and two dogs.

We are planning a modular and secure setup that can be (de)installed quickly and easily. After a year in lockdown we want to get something built quickly so that we can enjoy the warmer weather, while also maximising our ability to customise our setup over time. The ultimate goal is to build a drawer system with a sliding top, but the immediate goal is to build a basic box that we can slide our Plano boxes under, with extending rails on top so that we can lay out a bed for us and the hounds and get out into the mountains.

We travel light - camping and hiking kit, standard recovery gear, compressor, and don’t yet have but are planning to buy a fridge. We want to maintain access to the underfloor storage if possible, but concede that anything we build into the cargo area may make that difficult. Short term may not be a problem, but building in drawers likely means we will lose ease of access, so it would be more likely to house a house battery setup in future.

There seem to be two primary building materials for the frame — 8020 aluminium extrusion, and square aluminium tubing with ABS connectors. We have neither the skills or ease of access to a shop to weld. We have a mitre saw and aluminium blade, so we can cut either to length as required. I’ve thoroughly researched the options and it seems that the primary considerations are:

• materials cost (extrusion vs tube)
• connectors cost (extrusion fittings can be expensive)
• strength to weight ratio (extrusion is heavier but considerably stronger)
• modularity (there are significantly more options with extrusion, and if we plan it right, we can add components to it over time)
• ease of modification (extrusion framing requires more consideration than tubing)

It seems to me that aluminium extrusion is the right material for our needs, but if we don’t want to burn cash on materials we would need to spend considerably more time planning - making sure we have the right profile and connectors so that we don’t have to replace any of the core framing components in the future (Building a box is not the same as building a drawer system).

i’m curious to hear from others who’ve been this route, including any feedback on choosing the right profile for building a cargo solution that can take up to 200kg / 440lb (two humans and two big dogs) sleeping on top.

 

[bgenlvtex]

8020.net has load modeling software available for free use.

tnutz.com will sell you cut to length (accurately) extrusion saving some work for a very modest cut charge.

Connectors are a little high, but if you are going to skin it with some type of board the board itself serves to unify the structure lessening the need for some connectors.

 

[socal66]

Dan Grec recently did an overview of the storage cabinets he built using aluminum tubing and connectors for his Jeep and how that has worked out in his travels.

 

[uncompromise]

curious to know if we went the extrusion route if 2020 is enough for the frame, or if we need to bump up to 3030; have spent hours trying to find an answer, but so far, google, YouTube and all of the various forums don’t provide any clarity whatsoever on this point. 2020 Is significantly cheaper and lighter, and seems to be standard for cabinets. I have zero interest in overbuilding / overspending and over-weighting our vehicle, so don‘t want to do what so many vanlifers seem to do which is overbuild rather than do the necessary math to build right. I know that 3030 would be fine, but if we can manage with 2020 it would make it much easier to get the thing in and out of the vehicle when we don’t need it.

 

[uncompromise]

Adding to this thread in order to get feedback on what we're proposing to build, and specifically if it will be strong enough to put it together this way

• 12mm plywood base, bolted to the floor
• 25mm square aluminium tube, with steel reinforced connectors
• 12mm plywood top, bolted to the frame
• 12mm plywood extender, hinged in the middle with a piano hinge and with another piano hinge to the leading edge of the plywood top
• 5mm flat aluminium profile screwed into 5 vertical aluminium tube supports
• 2 heavy duty drawer slides to hold up to 200kg in weight (two adult humans and two dogs) attached to the outer edge of the frame

My concerns are that, even with the frame being attached top and bottom to a strong plywood base, that attaching the drawer slides to the outside of the frame might be unstable -- which is why I've added so many vertical supports on each side. If that's overkill, please let me know.

We had originally thought to take @Michael's drawer designs and modify them to our vehicle, however we don't have access to a reliable fabricator, and don't believe that we can build out his design using either aluminium tube and connectors or 2020 aluminium profile. We are trying to build something inexpensive and light so that it can be removed relatively easily from the vehicle if/when we want access to the full cargo space.