Aluminum alloy selection

[moroza]

I'm building my own hard-side truck camper, and after finding out that all of the following materials (except 2024, which I haven't looked into yet) are available and within budget, I'm trying to decide what alloy to use.

The application is the underside (bed will be removed), walls, and roof - complete outer skin. I'm trying to strike a balance between weight, strength, and damage resistance. Framing will be a fairly sparse cage of square tubing, with wood filling in in less-critical sections (mainly as skin stiffeners). The skin is supposed to be a stressed member.

2024? Corrosion doesn't matter much since I'm painting the whole thing anyway. Aircraft use this stuff where it needs to be able to absorb damage. It appears to have the best fatigue resistance of common alloys. It's almost as strong as 7075. I don't know what it costs yet.
5052? It's weak, but relatively malleable, more likely to dent than puncture.
6061? It's the middle ground between 5052 and 7075, but as brittle as the latter.
7075? It's extremely strong (more than mild steel, per thickness) but quite brittle.

I'm undecided between 0.040" and 0.063" thickness, leaning towards the former for 70lb weight savings, and relying on field-replacement of any punctured panels. Thoughts?

It'll all be riveted with angle brackets on the inside, directly to the skin on the outside.

The frame is to be 2"x0.125 square tubing of 6061 alloy, primarily because at first glance, I can't get it in anything but 6061 and 6063. I could look harder for tubing out of something stronger, like 2024 or 7075. Should I bother?

 

[incognito]

Hy,

those aluminium grade numbers doesn,t tell me much.
using aluminium I really don<t know if it is a good bet because it will probably be heavier than a well insulated solid fiberglass like Bigfoot. in fact Bigfoot 3000 has a aluminum frame structure and a 2 inch insulation and comes at more than 1400 kgs( more than 3000 lbs) on sticker . in fact was so heavy when I went to scale (mine was4000 lbs empty ) .it was so heavy for my offroad needs that I<ve sold it after 3 month of ownership to a guy who stayed only on highway. Otherwise with the fibercore wall system( google it) maybe is the best truck camper ever.

found a blog of A DIY homebuilt truck camper and spend 12000 $ in materials and 8 month of work. at this price you can find a good used Bigfoot or Northern Lite camper and improve it to suit your needs. Starting from o is usually a lot of work . Also another problem is the resale value also Like in Diy boats doesn<t resell well.
sorry just want to save you 8 months of work so you could start travel sooner
have safe travels
incognito

 

[Capt Eddie]

I would not build my own camper body. Buy an aluminum truck box. They are far better engineered then what I could build. Then all you have to do is finish the inside. Look at Silver bullet. It started life as a UHaul box. If you are planning a fully functional camper. With A/C, heater, stove, frid. Be prepared to spend about $30K to build yourself a truck camper. Plus all the time you will have in it. At this stage of my life, my free time cost double what I make per hour working. I cherish my time with the family.