Steel vs Aluminum tubing (Camper frame)

[Recovry4x4]

I'm probably out of my league but have you considered hat channel instead of box?

 

[montaillou]

I'm probably out of my league but have you considered hat channel instead of box?

Well, to be honest, I only sparsely looked at other options. I'm happy to consider other options, really the reason why this thread exists.

I want the roof to hold a fair bit of weight from below and not give when you walk on it and squares seemed like a good way to go. It's a rather small application. I will be suspending things from below and having a tube seemed an easy way for me to go.
Doing a quick web search, the hat channels I'm seeing that are heavy gauge are aluminum, and I'm sure steel ones exist, but if they're not common they're gonna be expensive.
At this point, I think I'm gonna stay away from aluminum for several reasons, I'm not very confident welding it, it's considerably more expensive than steel and flexes more, also possible galvanic issues where the aluminum contacts the steel of the truck.

I also looked at channel steel, but tube is stronger. Of course, if I can find a source that is substantially cheaper and offers what I need, I would almost certainly go with that. Maybe a local supplier will have an abundance of rectangular over square, for instance. I'm looking at around 1k lbs in tubing, so, I'll probably be buying it local.

 

[Jbulach]

Yep, all that tubing is going to get heavy. 4” Junior i beam trusses and hat channel stiffeners would likely be twice as strong and half the weight, if you can spare a few inches of height. Also skylights and solar panels don’t mix well with foot traffic, if you working on a party deck?

 

[Another Ahab]

There will be a rather sturdy door on the tailgate side, and a roll-up door on the cab side. No windows, but skylights. I'm also thinking if I can make it so one wall section on each side (driver/passenger) moves straight up inside a frame to create a cross breeze when parked. The exterior skin is 1/4" faced with aluminum on each side with a core of plywood.

Wondering if you might find a similar aluminum-skinned sheet product, but with a honeycombed core:

- It would give you more (minimal maybe, but more) insulation value

I don't know though that there even IS such an "animal" out in the marketplace.

Somebody else here might, and in the meantime I'll take a look....

 

[Another Ahab]

Wondering if you might find a similar aluminum-skinned sheet product, but with a honeycombed core:

Somebody else here might, and in the meantime I'll take a look....

Found some product, but not running across any that's aluminum-skinned:

- it's just an idea...

https://www.plascore.com/honeycomb/honeycomb-panels/

 

[Reworked LMTV]

I have been looking at what you are talking about, for about three years. Here are my thoughts:
1. Make sure that you can insure it when you are done.
2. Start with someone else's proven design first. These will likely meet DOT regs in a general way. For example, buy a used camper frame, maybe salvage and convert. The design has already been proven.
3. Use FRP panel sides, as they are very strong and very light.

 

[montaillou]

Yep, all that tubing is going to get heavy. 4” Junior i beam trusses and hat channel stiffeners would likely be twice as strong and half the weight, if you can spare a few inches of height. Also skylights and solar panels don’t mix well with foot traffic, if you working on a party deck?

I looked at I beams, even small ones are too big. I'm already pushing 11'+ and I'm gonna be mounting things from the ceiling, I don't want to stoop when walking around. I'm making the crawl space as low as I can but need it to be high enough to have the fuel tank (it'll be a fuel cell) work. Also, if I put the ammo cans there, they're about 7" high and I don't want ANY weight to be applied to the tank or the ammo cans. The tank & the cans will need to be accessed and possibly removed and the crawl space will be designed with this in mind. And as to saving money/weight (see below for argument) it's such a small job that I don't know that I'd be saving so much to make it worth it.

If I go with 18" OC, I'd be looking at 9 pieces, if I go with 24", it's 7 and I'd be saving ~$200 and ~110lbs. As to the strength, and the solar panels on the roof - it won't be a party platform, most of time it'd be just me, maybe up to 4 ppl and I'm only planning on putting up 2 solar panels and I might make a collapsible cover that would cover the panels (and ride beneath them when not in use) to cover them if more than myself is on the roof. The skylights will have lockable, retractable sliding covers as well, mostly for security.

Found some product, but not running across any that's aluminum-skinned:

- it's just an idea...https://www.plascore.com/honeycomb/honeycomb-panels/

I had looked at these, in fact, it's how I found the panels I plan to use. I have to find a balance between weight and cost. In rough terms, the camper will be a little over 7 feet high, but let's use 7 just for simple calculation. Also the overall dimensions will be roughly 7' 3" x 12', again, let's use 7' x 12', so that comes out to around 434 sq/ft (roof, 4 sides, interior floor). Maybe I'll go with something simple for the interior floor, it doesn't have to be as weatherproof/durable as the exterior so, that's still around 350 sq/ft. Those aluminum honeycomb panels are going for, roughly $15 sq/ft. Now, that's just one site and maybe if I shop around I can find them cheaper, but that's a starting point. And they weigh about 0.8 lbs sq/ft. The panels I'm currently looking at are half the price and almost double the weight. But, it's a deuce, I do have 5k lbs to work with. Now, I would like the finished camper to come in below 2500 lbs, then I add fuel to the tank in the bed and water (~100 gal), and I'm up to about 4k lbs, still 1k below the 5k threshold. Right now, in rough numbers the steel tubing is coming in around 1k lbs, the outer panels around 500 lbs., but if I went with the honeycomb panels I could save 250 lbs but it'd cost an additional $2500. To me, the cost benefit ratio doesn't work. I have a flexible budget, but it's not unlimited.

1. Make sure that you can insure it when you are done.
2. Start with someone else's proven design first. These will likely meet DOT regs in a general way. For example, buy a used camper frame, maybe salvage and convert. The design has already been proven.
3. Use FRP panel sides, as they are very strong and very light.

1) Yep, been saving receipts, spoke to my agent about this already and they said if I can show what I paid they can look at doing this.
2) The problem with going with a mass produced item is they're approaching it from a different angle, making money the cheapest way they can to produce something that works for lots of people. I'm in a deuce. Right away I'm in different territory. I originally considered a S-280 communications shelter (for about 2 years). However, finding one and getting it to me would likely cost at least $2k - $4k and I'd still want to modify it heavily. It just seemed the best option would be to design something from the ground (or bed) up and try to think of everything I want to do and consider how it'll all fit together. Camper frames are not designed to be 7' x 12'. And as I hope to use this for very extended trips I want squeeze all the space I can out of this. There are trucks like what I have in mind out there, they start at around $500k - out of my price range, but I think I can have something similar(better in some ways) for well under 1/10th the cost.
3) Never heard of FRP panels. But, as I look them up I see they're not designed for exterior use and I hope this thing gets a lot of exterior use. Also, FRP panels aren't UV resistant, and to me that means they won't hold up well over the years. The panels I've found (and I'm still looking) so far look very promising and are used as the skin for office buildings so they're designed for the elements. One of the reasons I'm not going with plywood is because I don't think it'll weather well, and constant exposure (I live in a wet climate and don't have storage big enough to store this inside) to wind/rain would lead to expansion of the wood and probably a lot of maintenance. I also want something that is tough to get through, as I told one salesguy, I would rather wake up to finding someone trying to break in than wake up to someone standing over me.

 

[Reworked LMTV]

If you are not familiar with FRP, I have a lot of questions. FRP are used by most of the major overlanding companies. Global Expedition Vehicles, Earthroamer, Total Composites. Not UV resistant? Where are you getting your info from? I've been researching this for a long time. Years. I speak with experts on build construction. Thankfully, many of my ideas were shot down. They have been here. I have spoken with Ulrich Doldle about my ideas while he traveled Europe. Who is Ulrich you say? Oy.....
Discussed many types of construction. Aluminum, steel, fiberglass, etc. If you want to best in Overlanding, look to the Germans and Europeans. They have been doing Overlanding for years. Didn't see at the Biltmore last year for the Overlanding Expo. Where you there?

So what are two MAJOR problems with these builds. Thermal bridging and mold. Plywood is actually a great building material IF you seal it in epoxy or similar. Talk to the at people Gougeon Brothers / West system.

I looked at I beams, even small ones are too big. I'm already pushing 11'+ and I'm gonna be mounting things from the ceiling, I don't want to stoop when walking around. I'm making the crawl space as low as I can but need it to be high enough to have the fuel tank (it'll be a fuel cell) work. Also, if I put the ammo cans there, they're about 7" high and I don't want ANY weight to be applied to the tank or the ammo cans. The tank & the cans will need to be accessed and possibly removed and the crawl space will be designed with this in mind. And as to saving money/weight (see below for argument) it's such a small job that I don't know that I'd be saving so much to make it worth it.

If I go with 18" OC, I'd be looking at 9 pieces, if I go with 24", it's 7 and I'd be saving ~$200 and ~110lbs. As to the strength, and the solar panels on the roof - it won't be a party platform, most of time it'd be just me, maybe up to 4 ppl and I'm only planning on putting up 2 solar panels and I might make a collapsible cover that would cover the panels (and ride beneath them when not in use) to cover them if more than myself is on the roof. The skylights will have lockable, retractable sliding covers as well, mostly for security.



I had looked at these, in fact, it's how I found the panels I plan to use. I have to find a balance between weight and cost. In rough terms, the camper will be a little over 7 feet high, but let's use 7 just for simple calculation. Also the overall dimensions will be roughly 7' 3" x 12', again, let's use 7' x 12', so that comes out to around 434 sq/ft (roof, 4 sides, interior floor). Maybe I'll go with something simple for the interior floor, it doesn't have to be as weatherproof/durable as the exterior so, that's still around 350 sq/ft. Those aluminum honeycomb panels are going for, roughly $15 sq/ft. Now, that's just one site and maybe if I shop around I can find them cheaper, but that's a starting point. And they weigh about 0.8 lbs sq/ft. The panels I'm currently looking at are half the price and almost double the weight. But, it's a deuce, I do have 5k lbs to work with. Now, I would like the finished camper to come in below 2500 lbs, then I add fuel to the tank in the bed and water (~100 gal), and I'm up to about 4k lbs, still 1k below the 5k threshold. Right now, in rough numbers the steel tubing is coming in around 1k lbs, the outer panels around 500 lbs., but if I went with the honeycomb panels I could save 250 lbs but it'd cost an additional $2500. To me, the cost benefit ratio doesn't work. I have a flexible budget, but it's not unlimited.



1) Yep, been saving receipts, spoke to my agent about this already and they said if I can show what I paid they can look at doing this.
2) The problem with going with a mass produced item is they're approaching it from a different angle, making money the cheapest way they can to produce something that works for lots of people. I'm in a deuce. Right away I'm in different territory. I originally considered a S-280 communications shelter (for about 2 years). However, finding one and getting it to me would likely cost at least $2k - $4k and I'd still want to modify it heavily. It just seemed the best option would be to design something from the ground (or bed) up and try to think of everything I want to do and consider how it'll all fit together. Camper frames are not designed to be 7' x 12'. And as I hope to use this for very extended trips I want squeeze all the space I can out of this. There are trucks like what I have in mind out there, they start at around $500k - out of my price range, but I think I can have something similar(better in some ways) for well under 1/10th the cost.
3) Never heard of FRP panels. But, as I look them up I see they're not designed for exterior use and I hope this thing gets a lot of exterior use. Also, FRP panels aren't UV resistant, and to me that means they won't hold up well over the years. The panels I've found (and I'm still looking) so far look very promising and are used as the skin for office buildings so they're designed for the elements. One of the reasons I'm not going with plywood is because I don't think it'll weather well, and constant exposure (I live in a wet climate and don't have storage big enough to store this inside) to wind/rain would lead to expansion of the wood and probably a lot of maintenance. I also want something that is tough to get through, as I told one salesguy, I would rather wake up to finding someone trying to break in than wake up to someone standing over me.

 

[Another Ahab]

So what are two MAJOR problems with these builds. Thermal bridging and mold. Plywood is actually a great building material IF you seal it in epoxy or similar. Talk to the people Gougeon Brothers / West system.

Marine-Grade plywood (waterproof glue between plies) has a long history of "doing the job":

- PT Boat, Minesweepers, Spruce Goose, Luftwaffe (Ta-154), it goes on and on

Like LMTV notes. It just wants an appropriate exterior skin, and paint (epoxy, enamel, aluminized) is one of the options.

Just a thought.

 

[Reworked LMTV]

Until I looked at the science, I thought plywood was a lame choice for most applications. Sealed in fiberglass or other polymer, this stuff is a beast and relatively light weight, given its strength. With epoxy, you can greatly change the characteristics of plywood. Add silica or fiberglass, or microspheres, depending on your application, and you can do amazing things.

Marine-Grade plywood (waterproof glue between plies) has a long history of "doing the job":

- PT Boat, Minesweepers, Spruce Goose, Luftwaffe (Ta-154), it goes on and on

Like LMTV notes. It just wants an appropriate exterior skin, and paint (epoxy, enamel, aluminized) is one of the options.

Just a thought.

 

[montaillou]

If you are not familiar with FRP, I have a lot of questions. FRP are used by most of the major overlanding companies. Global Expedition Vehicles, Earthroamer, Total Composites. Not UV resistant? Where are you getting your info from? I've been researching this for a long time. Years. I speak with experts on build construction. Thankfully, many of my ideas were shot down. They have been here. I have spoken with Ulrich Doldle about my ideas while he traveled Europe. Who is Ulrich you say? Oy.....
Discussed many types of construction. Aluminum, steel, fiberglass, etc. If you want to best in Overlanding, look to the Germans and Europeans. They have been doing Overlanding for years. Didn't see at the Biltmore last year for the Overlanding Expo. Where you there?

So what are two MAJOR problems with these builds. Thermal bridging and mold. Plywood is actually a great building material IF you seal it in epoxy or similar. Talk to the at people Gougeon Brothers / West system.

I made this thread for ideas, not for gatekeeping. I am not questioning anyone's credentials or dismissing someone out of turn. I'm sorry I don't know who you are or your credentials. I'm not here to make something for the public or an awards show, this is my own private use and it's a one-off. I don't think someone has to know someone or been to some show to have some ideas. I occasionally face negativity on this site and really, if you have a problem with me you're more than welcome to just take a hike or a drive.

When someone suggests something, I do a web search (you're welcome to posts links) and when I look up FRP panels and "exterior use" I see a question about "Are FRP panels UV resistant" and the answer listed was "No". I also read the FRP panels are designed for interior use. Yes, I'm sure there are exceptions for everything, but once something moves from common to exception, the cost usually goes up, not down.

I will now do a web search for marine grade plywood and look for availability, weight & cost and do an analysis based on my needs.

This looks promising. I'm seeing prices of $55-65 for a 4' x 8' sheet and a weight of around 27 lbs. There will be extra costs for sealing it, but I can't see this amounting to a whole lot. It's probably not as rigid as the stuff I was considering, so I would probably use more supports on the walls, but even if the weight difference is a wash, it's still considerably cheaper.

 

[Reworked LMTV]

Do it your way. Good luck.

I made this thread for ideas, not for gatekeeping. I am not questioning anyone's credentials or dismissing someone out of turn. I'm sorry I don't know who you are or your credentials. I'm not here to make something for the public or an awards show, this is my own private use and it's a one-off. I don't think someone has to know someone or been to some show to have some ideas. I occasionally face negativity on this site and really, if you have a problem with me you're more than welcome to just take a hike or a drive.

When someone suggests something, I do a web search (you're welcome to posts links) and when I look up FRP panels and "exterior use" I see a question about "Are FRP panels UV resistant" and the answer listed was "No". I also read the FRP panels are designed for interior use. Yes, I'm sure there are exceptions for everything, but once something moves from common to exception, the cost usually goes up, not down.

I will now do a web search for marine grade plywood and look for availability, weight & cost and do an analysis based on my needs.

This looks promising. I'm seeing prices of $55-65 for a 4' x 8' sheet and a weight of around 27 lbs. There will be extra costs for sealing it, but I can't see this amounting to a whole lot. It's probably not as rigid as the stuff I was considering, so I would probably use more supports on the walls, but even if the weight difference is a wash, it's still considerably cheaper.

 

[montaillou]

Ok, so, I started looking at marine grade plywood which I discovered is really just plywood with a waterproof glue. It's also a little heavier than standard plywood. Regular 1/4", 4' x 8' plywood comes in at 22lbs (on average) and marine would be 27lbs, it's also about around $2 sq/ft, give or take a little.

Now, it'll have to be faced and I want something tough as I'm gonna freezing temps, lots of rain and potentially salt spray, desert conditions and everything else that I can't think of.

Some of the stuff I've looked at was across the country and I really would like to save those freight charges.

I found some stuff local (100 miles away) that is plywood faced with a thin skin aluminum designed for exterior use. It's 1/8", 4' x 8' at 23 lbs and costs about the same (or less) than marine plywood. They make a 1/4", but it's half again as expensive and weighs more. I'm gonna get down to their shop and see which might work. If anyone interested, it's called Max-metal, and it's designed for signs.

For what it's worth, I didn't start this thread to parrot my own ideas. I have gotten many ideas from SS in general. Many I don't know that I would have ever thought of (just recently, washers for battery terminals as an example). Also, I was looking at a plastic to use as shutters and someone here turned me onto ballistic fiberglass and because it's SO cheap (and the weight is ok) compared to anything else I've found I've decided to go with that for a couple of applications.

I am really very grateful for the opportunity to use this website to bounce ideas off other people and to get feedback and suggestions. It may seem like I'm arguing points, but I do have a picture in my head of what I think will work, but if something else is suggested I will look into it and am not afraid to consider what I don't know or ask.

 

[Another Ahab]

I found some stuff local (100 miles away) that is plywood faced with a thin skin aluminum designed for exterior use. It's 1/8", 4' x 8' at 23 lbs and costs about the same (or less) than marine plywood. They make a 1/4", but it's half again as expensive and weighs more. I'm gonna get down to their shop and see which might work. If anyone interested, it's called Max-metal, and it's designed for signs.

Who knew?!

Good to know. Thanks!

 

[rustystud]

Ok, so, I started looking at marine grade plywood which I discovered is really just plywood with a waterproof glue. It's also a little heavier than standard plywood. Regular 1/4", 4' x 8' plywood comes in at 22lbs (on average) and marine would be 27lbs, it's also about around $2 sq/ft, give or take a little.

Now, it'll have to be faced and I want something tough as I'm gonna freezing temps, lots of rain and potentially salt spray, desert conditions and everything else that I can't think of.

Some of the stuff I've looked at was across the country and I really would like to save those freight charges.

I found some stuff local (100 miles away) that is plywood faced with a thin skin aluminum designed for exterior use. It's 1/8", 4' x 8' at 23 lbs and costs about the same (or less) than marine plywood. They make a 1/4", but it's half again as expensive and weighs more. I'm gonna get down to their shop and see which might work. If anyone interested, it's called Max-metal, and it's designed for signs.

For what it's worth, I didn't start this thread to parrot my own ideas. I have gotten many ideas from SS in general. Many I don't know that I would have ever thought of (just recently, washers for battery terminals as an example). Also, I was looking at a plastic to use as shutters and someone here turned me onto ballistic fiberglass and because it's SO cheap (and the weight is ok) compared to anything else I've found I've decided to go with that for a couple of applications.

I am really very grateful for the opportunity to use this website to bounce ideas off other people and to get feedback and suggestions. It may seem like I'm arguing points, but I do have a picture in my head of what I think will work, but if something else is suggested I will look into it and am not afraid to consider what I don't know or ask.

Thanks for the "heads up" on the "Max-Metal" . Is the shop down here in Seattle ? I wonder how the 1/4" would hold up for side walls on a RV set up ? I'm thinking about building a RV style camper in the bed of the Deuce for the "Great Alaskan Adventure" . I was just going to bring my travel trailer and load the bed of the deuce with supplies. Now that I've been modifying the crap out of my M105 with the S250 shelter on it, I'm thinking of taking that instead. If I do then I need a place for my son and me to sleep/stay in for the 1,400 mile trip.

 

[montaillou]

Is the shop down here in Seattle ?

It's in Tukwila, near Southcenter Mall. They don't have any samples for the 1/4" so I'm just gonna go there, probably next week, to take a look at the sheets. They carry other panels so I figure I'll just look around. They don't list weights/prices on their web site which is a little annoying.

I should mention that this place is part of a nationwide chain, mostly in Western, Central & Eastern time zones (sorry, Mountain )

 

[Another Ahab]

I'm thinking about building a RV style camper in the bed of the Deuce for the "Great Alaskan Adventure" . I was just going to bring my travel trailer and load the bed of the deuce with supplies. Now that I've been modifying the crap out of my M105 with the S250 shelter on it, I'm thinking of taking that instead. If I do then I need a place for my son and me to sleep/stay in for the 1,400 mile trip.

Sweet, rustystud!

I'm going to start stocking up all my popcorn for THAT thread, right now.

 

[davidb56]

Im not sure, but I think LMTV might have been referring to FRP-SIP panels, and not the ones at Home Depot for bathroom walls etc. The SIP panels are "cored", and have UV inhibiters in it. They have a "R value" of maybe r13, and need little frame work, if any at all. The West Epoxy System has been around for decades and is used a lot in canoe building and small boats as its real expensive. There is all kinds of additives that can be used with it for strength and filler type properties. I just used it as a glue in place of Resorsinal (spelling ?) because mixing a powder was a pain, and West has a pump.

 

[rustystud]

Sweet, rustystud!

I'm going to start stocking up all my popcorn for THAT thread, right now.



View attachment 783527

 

[montaillou]

I did a 20 min search on FRP SIP panels. Mostly I come up with manufacturers that don't list prices which doesn't always mean that they won't sell small quantities, but I'd want to find one in my area to avoid freight. I did find some snippets on a couple of sites, one that has thickness of 4"+ which is too thick for my purpose.

While insulation seems like a good idea, I'm dealing with a small space. I plan to have an abundance of electricity and if I'm in colder areas, a wood stove (10" x 8" x 15") which throws out a min of 3k btu's. This was designed for boats, comes with a heat shield and only needs 2" clearance.

I also found one site that listed the panels for over $100 for a 4' x 8'. Right now, my standard is under $3 sq/ft.