Truck Camper Aluminium Frame

[amad]

Hey guys,
I'm currently in the planning phase on my truck camper and I wanted you opinion on this:

My basic plan for the frame is to do the base with aluminium C-Channel 60x40x4mm (around 5-6 for the whole floor) and aluminium 30x30x3mm square tube for the whole frame.

Everything riveted with structural aluminium rivet (with alu angles) and construction adhesive (probably 3M 4200 or 5200 (If I want it super permanent)).

Then stuff like bracing/ corner.

and Finally ACM sheet with 3M VPH tape & Rivet around the perimeter (not in the middle to allow for small movement with temperature change).

I don't see myself welding and anyway I've read alot that welding aluminium weakens it, unlike steel that strengthen it. So my thought is that modern adhesive + rivet will be plenty good !

Hope to get you guys feed back

 

[carterd]

Lots of good info here and on related YouTube channel: https://forum.expeditionportal.com/...top-composite-camper-box-build-thread.241475/ :

 

[amad]

Lots of good info here and on related YouTube channel: https://forum.expeditionportal.com/...top-composite-camper-box-build-thread.241475/ :

Thanks I did not see it, I'll look at it !

 

[Peter_n_Margaret]

The best frame is none at all.
Fibreglass/closed cell polyurethane/fibreglass sandwich needs no frame.
Cheers,
Peter
OKA196 motorhome

 

[Fenderfour]

Hey guys,
I'm currently in the planning phase on my truck camper and I wanted you opinion on this:

My basic plan for the frame is to do the base with aluminium C-Channel 60x40x4mm (around 5-6 for the whole floor) and aluminium 30x30x3mm square tube for the whole frame.

Everything riveted with structural aluminium rivet (with alu angles) and construction adhesive (probably 3M 4200 or 5200 (If I want it super permanent)).

Then stuff like bracing/ corner.

and Finally ACM sheet with 3M VPH tape & Rivet around the perimeter (not in the middle to allow for small movement with temperature change).

I don't see myself welding and anyway I've read alot that welding aluminium weakens it, unlike steel that strengthen it. So my thought is that modern adhesive + rivet will be plenty good !

Hope to get you guys feed back

Welding aluminum does weaken it, but usually not enough to matter. It locally removes the heat-treatment, which does provide a lot of structural strength, but it doesn't fully remove it. To get to O state, aluminum needs to be held at a high heat (570 + degrees) for 3+ hours. If aluminum could be fully annealed faster with higher temperature, it would be the standard process. Without localized testing, we don't know how much strength is lost with welding, but it's probably just a bit. 6061 T6 (common extrusions) have a yield of 35 ksi. Annealed 6061 has a yield of around 16 ksi, so you could lose half your strength, but that's not going to happen, and it will be localized to the HAZ.


Welding aluminum isn't hard if you have a little experience. 4mm wall can be welded with a Pulse Mig + spoolgun. YesWelder has units around $300. Add a tank of Argon and you can get started.

Rivets are a good alternative. Keep some good edge margins (3X diameter) to avoid cracks forming. Adding ACM using VHB can be tricky with riveted builds since it wants a flat surface to adhere to. Stacked brackets and rivet heads can interrupt this surface. You probably want to look at countersunk rivet heads and plan bracketing to the inside. Dewalt has a powered rivet gun that will save an immense amount of discomfort from repetitive squeezing. I have a slightly used tool I could sell at a discount.



I do recommend taping the ACM all the way down the camper. It will limit oil canning and vibrational noise. Get 'real' VHB. A lot of the stuff on Amazon is similar-to, or expired product. GO to an industrial supply house to get it. A 3/4" x 50 yd roll costs ~$100. Its not cheap. ACM + VHB will add a lot of structural rigidity to the camper which is good overall, will support the rivets, and help prevent cracks.

 

[rruff]

Hey guys,
I'm currently in the planning phase on my truck camper and I wanted you opinion on this:

The best frame is none at all.

If it's a well made camper on a fully boxed truck chassis, then you really don't need a subframe... or something minimal would be sufficient. If you want to take the camper off and haul loads, that's a different scenario. If you have a C-channel chassis with a lot of torsional flex, that is yet another scenario.

So... more details are needed...

 

[amad]

If it's a well made camper on a fully boxed truck chassis, then you really don't need a subframe... or something minimal would be sufficient. If you want to take the camper off and haul loads, that's a different scenario. If you have a C-channel chassis with a lot of torsional flex, that is yet another scenario.

So... more details are needed...

It's not a fully boxed truck but a chassis Mitsu Triton truck. Hence why I'm building a thinker floor.
Hopefully there won't be too much flex tho, I don't plan on going really off-road other then gravel roads !

 

[rruff]

That's a midsized pickup, correct? "Fully boxed" refers to the cross section of the frame rails. The other option would be open-C, but most likely it's boxed. You need to know before you start.

If it's boxed you can attach the camper right to the chassis... save yourself some time, money, and weight.