DIY Pop-up Flatbed Truck Camper with shower for 1/2t

[MrGrodskyi]

Hi, I am starting to build my soft pop up camper for a 1/2-ton truck with 6`5`` bed. (Perhaps a hard side in the future).

I want to share my design and plans, and maybe get some criticism on how to improve.

Design:

I am trying to make something close to this design. I won't have a special bed. Direct attachment to the frame, through something that will allow the frame to flex.

I planned to use 1x1 and 1x4 square aluminum tubing with 1/8 wall. I plan to use rivets to fasten the frame. Also, add steel or aluminum bars over the joint (since these are square pipes and they do not intersect.

External and internal sheathing should be made of AСM. For gluing the panels I will use Sikaflex and possibly rivets, adding modding from an aluminum half-square at the joints.

For insulation, I will use 1 inch of Extruded Polystyrene from Home Depot in the walls (between the aluminum tubes) + 0.5 inch on top to cover the aluminum tubes.

But recently I heard the opinion that a steel square 3/4 x 3/4 1/16 has only slightly more mass (0.6lbs/ft) than an aluminum square 1x1 1/8 (0.52lbs/ft). It got me thinking.

Using steel I can weld it without any problems, also without using extra plates which also add weight.

Also by using steel, I think I will be able to reduce the size of the square at the top of the bed which will also reduce the weight.

The steel is also 50% cheaper compared to 6061

So I see a lot of upside to using steel, and only a small downside, possibly adding 10%-15% weight.

I am critical of the weight as it is only a 1/2-ton truck. But I think it's worth it. What is your opinion?

Should I be concerned about the contact of aluminum panels with steel?
Theoretically, the glue should separate them.

Should I be worried about moisture in the steel and rust? I don't plan on this camper for 30 years. But would not like to get rust after 1-2 years.

To be continued....)

 

[Ozarker]

Use aluminum, it will be worth more to you and who ever you sell it to years from now.

 

[97heavyweight]

I would steer away from the sikaflex to bond the ACM to frame. I have had several issues with the sikaflex being used to bond gasket to frame or even ABS to metal.

I used a knock off of 3M VHB tape that is good for 15lbs/in. I have seen no failures in three years of hard use and it is much easier to use and cheaper I believe.

You could also look into extruded aluminum. It would be more expensive, but you can machine it so you can utilize internal fasteners.

I would add height to the frame so that the bedding area is deeper. I made mine with only a 6" deep wall at the bed and regret it. I can only store half the mattress and one sheet with the roof closed.

 

[MrGrodskyi]

I would steer away from the sikaflex to bond the ACM to frame.

I am now thinking of completely abandoning the ACM, and using sheet aluminum 1/16, which will serve me as overlays at the connection points, to strengthen it.

1/16 has approximately the same weight as 1/8 ACM.

it also gives me a sturdier outer shell since it's thick aluminum.

absence of an inner layer of aluminum on which condensation can form.

I would add height to the frame so that the bedding area is deeper. I made mine with only a 6" deep wall at the bed and regret it. I can only store half the mattress and one sheet with the roof closed.

yes, I know it needs to be done higher, but I haven't decided how much yet. I originally thought of doing this on the lid as well, but that would add weight to it, but also stiffness

 

[MrGrodskyi]

now I'm thinking about doing 100% of the design on the computer and ordering the cutting right away, do you think it's a good idea?

 

[Fenderfour]

if you can weld steel, you can weld aluminum. the Yeswelder Mig 250 pro can do it natively down the whip. It's just a little trickier than steel and needs a little more prep.

If i were to do it again, I'd probably make a steel frame. I think the big thing I'm bumping into is the need to have fastening locations on the frame. if i had used steel, I could add plates with threaded holes, of just weld bungs and nuts on places. These are possible with aluminum, but less robust and more expensive.

I'd recommend against moving too fast. It's easy to buy parts and things. It's hard to think them through. Spend a little time, make some cardboard mockups, maybe do some calculations on the cabover to make sure it's as rigid as you think it is. This thread has some instructions how to calculate deflection for a beam

 

[MrGrodskyi]

maybe do some calculations on the cabover to make sure it's as rigid as you think it is. This thread has some instructions how to calculate deflection for a beam

Thanks for the link.
So I worry about transferring the load from the platform above the cab to the main structure.
This beam calculator is good, but my concern is more about attaching the platform to the frame and the direction of force that will apply to the frame.

if you can weld steel, you can weld aluminum. the Yeswelder Mig 250 pro can do it natively down the whip

I might go for aluminum welding, but don't want to invest $500+ in equipment. Also after welding it will become more brittle, I don't know how important it is to me

If i were to do it again, I'd probably make a steel frame

in one of the designs on this forum, the author complained that his steel squares of 1/16 thickness would deform after welding due to the temperature. it makes me sad too

 

[Fenderfour]

Well, you do you. I can feel your enthusiasm, and I'm sure you will have a lot of fun building your camper.