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OT: I am considering building a trailer- sub frame out?

Trboatworks

Diamond
Joined
Oct 23, 2010
Location
Maryland- USA
I have this camper trailer ideal kicking around.
It’s a full custom job not in market so sort of meets that criteria of only build if you can’t buy it..
Sooo...- I care most about what happens above the frame so getting this part built would save plenty of time and design work.

Box footprint is 7.5’x14’ so a 20’ or so sub frame.
Trailer is of ‘pop-up’ variety so low side walls set on deck set on frame.
I am guessing I would have just frame built with axle, springs tongue setup.
I want to go aluminum and the all up weight of rig and gear sup 3k so single axle.
Bent I beam construction would be nice I suppose for frame.

So anyone deal with frame makers for trailers.
Am I saving anything getting a pro shop to put this together or should I just add to list of the things I need to figure out and weld up for this project?
Another approach is just to get a shop to bend the two rails and go from there.
 
I have built about a dozen trailers in my career but never one out of aluminum. If you have TIG or a spool gun I would consider building it yourself. The undercarriage is off the shelf at places around here like Northern Hydraulics and Tractor Supply. They are relatively cheap even after you buy the rims and tires. They are designed for DIY projects and are very easy to hang under a frame. I have even used a tape measure to get the alignment right with good results (years of use with no apparent scuffing). Even though you will save some weight, AL would not be my first choice. I would use angle iron and weld it up in an evening. I prefer the forgiveness in an angle iron frame due to flexing. All the pieces are readily available (jack, tongue hitch etc.) but not in AL. Another reason why I would use steel.
 
Thanks- aluminum choice just to keep the trailer light and beat the rust problem.
I haven’t worked out the particulars but was thinking aluminum for everything from frame, deck framing on up to skirt walls, bunk framing etc.
At any point I could switch up- steel sub and aluminum deck framing etc.

It might be wrong thinking to think aluminum is needed at all but I am in the marine industry and seeing lots of nice rigs done up with it.
I have 250 amp tig so probably enough even for frame rails.
Have a buddy to lean on with a 350 who is a snap with al tig if needed.
 
Would you use 6061 if deciding on Al? Would you care that the welded areas will be at T0, meaning that the points of (likely) highest strain will be soft? If I went Al, I'd probably go with bonded/bolted joints, with shear plates as intermediary or sandwich elements. Use galvanized fasteners to minimize corrosion risks.

I like aluminum for a lot of reasons, but for a trailer frame I'd use steel, and have it either hot dip galvanized (after I was sure I was done with any needed tabs, etc.), or prepped and powder coated by a reputable company.
 
Thanks milland.
I understand the soft issue well enough though weld fabrication is not my primary work.
One thing I observe in marine practice is 6061 routinely used for high stress applications in spar work with no post weld tempering.
Not a argument but it I am surprised to see tangs, masthead cranes etc with high cyclic loads made up in this manner and failures are not common.

The welder here talks more technique in fillet placement, terminations etc being key.
And mass- big plate/large fillets and I guess flex is controlled.
I spoke with him a few times about this project and he off hands it - “yeah, I can weld it up- no problem.”

I need to get some particulars on paper for this - I don’t know much about trailer design.
My interest here is the canopy frame work: struts, tensioned wire and the like.
I need a frame and body to build on- I have no interest in trying anything novel on those parts- it’s well known craft.
I’ve just glanced at the rigs around in aluminum.
I am out at shop tomorrow- will look about.
 
I wonder if a lot of the Al used in boat stuff is mostly in compression, and the parts are designed so they don't see a lot of bending or twisting in use. Being a land lubber, I don't have enough "feel" for boat design (which hasn't stopped me from designing satellite and automobile hardware even though I'm not an aeronautical or automotive engineer).

A trailer frame will see a lot of low to high frequency vibration as it trundles down the road, so bending/twisting/fatigue must be considered. Al is usually treated differently than steel from a fatigue life standpoint, which is why I go for stiffness (along with strength) for the loaded aluminum parts I've designed for automotive use. High stiffness, less flexing, longer practical life.

Hope you'll keep a build thread.
 
I have this camper trailer ideal kicking around.
It’s a full custom job not in market so sort of meets that criteria of only build if you can’t buy it..
Sooo...- I care most about what happens above the frame so getting this part built would save plenty of time and design work.

Box footprint is 7.5’x14’ so a 20’ or so sub frame.
Trailer is of ‘pop-up’ variety so low side walls set on deck set on frame.
I am guessing I would have just frame built with axle, springs tongue setup.
I want to go aluminum and the all up weight of rig and gear sup 3k so single axle.
Bent I beam construction would be nice I suppose for frame.

So anyone deal with frame makers for trailers.
Am I saving anything getting a pro shop to put this together or should I just add to list of the things I need to figure out and weld up for this project?
Another approach is just to get a shop to bend the two rails and go from there.

Trailmanor.......Seems to answer most of your points.

2720 Series - TrailManor™
3130 lb dry

Used, you can find smaller models for less weight:
Full Specs for 2012 TrailManor Sport 2417 RVs | RVUSA.com
2,150 dry weight
 
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H&H has made alum trailers of many types for years, as well as Featherlight. Shouldn't be tough to figure it all out and make it work.
 
H&H has made alum trailers of many types for years, as well as Featherlight. Shouldn't be tough to figure it all out and make it work.

Thanks- looking at the flatbed H&H series it might be I could order a stripped down frame and go from there.

The heart of this thing is the top.
I need to build a functional model 1/5 scale and get concept sorted.
 
How much weight will it carry? Build some frame rails from aluminum channel if heavy, or tube if lighter loads. Dexter and Redneck Trailer sell a lot of axles around here. Do Not use mobile home axles! :)
 
Weight... I have no ideal.
Right now we are rednecking it- big tent and my old 6x10 utility trailer setup as a chuck wagon.
Bunch of gear thrown in the thing always looks overloaded.

I would guess less than 1000lbs for all the stores, water and gear.
Add another 1500 or so for the camper buildout?
 
My brother has a compact tractor with loaded tires. By purchasing an aluminum trailer, he saved enough weight that the combo was within the trailering capacity of his truck. The steel one put him well over the rated capacity of the truck. The trailer was significantly more expensive, but he can keep his truck, and continue to buy less expensive trucks in the future. Can't help with the brand.

The heat treatment question is interesting. I've seen big aluminum (tractor) trailers with welded I beams. Huge welds. Are 52' trailers heat treated> That would be quite a process.
 
This is sort of a family tradition.
As a very young lad my job was to hold the jar of pop rivets for my dad as he built out a pop-up camper on a old Model T chassis.

We family camped for many years in that till he bought a larger Starcraft pop up.

Nuts and trees.....

This is the tongue arrangement on a H&H aluminum flat bed:

763B0F34-6270-4510-A6BE-6498CF747456.jpg

The spec tables from these builders are not indicating what sort of spring setup is used.
Our box trailer has torsion bars which I seem to remember was described as a upgrade from leafs.
 
I know of a few home built campers/camper trailers. They ended up stupid heavy. Unless you are very familiar with travel trailers, you won't believe the incredibly light weight (read chicken $hit) construction methods they use.
 
I know of a few home built campers/camper trailers. They ended up stupid heavy. Unless you are very familiar with travel trailers, you won't believe the incredibly light weight (read chicken $hit) construction methods they use.

Thanks noted

I have some decent insights into sparse but quality construction methods so I might be able to land at good target weight.
No ply anywhere if I can help it.
It’s really just a lark but why not eh?
Except the time and money problem...

I am starting on a model next week.
If I can get this to work I will take off materials needed and estimate weight.
 
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If Boeing goes through a real slow-down, there might be a surplus of carbon fiber on the market...

Yeazzz .. and if you do the math... camping usually falling into a sub-section of life until kids are no longer kids, etc.

Of three Airstreams in a row bought used, Dad sold every one of them for more than he paid , off the back of doing maintenance and such including one detour to the factory for a whole new lower front after the Alcan highway gravel had trashed it.

You could get more enjoyment, sooner, safer, and cheaper, then exit very easily when the time comes by careful trading, plus a bit of the watercraft market skills applied to customization, of any of the better factory-built ones.

"Time" issue as much as money, too. Dad was already on a fair-decent retirement when he went into most of this.

Most home-brew - even well-done ones - end their lives as scrap, off the back of "unknowns" or "unprovables" .. licensing, insurance & c. comes time to shed them.

2CW
 
Bill I’ve been making backpacking and camping gear all my life.
I don’t start a project to save money, it’s about putting my ideals into form and enjoyment.
This is a fairly compelling design challenge to me and I am
not worried about resale value.
The value to me is in the build and use.

As I said above, I can’t buy a trailer like the one I am designing.
I have a interest in how these habitats are constructed to meet all the varied criteria of use.
I might not have the time for the project which would be a shame but that is the only limitation.
Too many projects- sometimes the really enjoyable ones are pushed aside for the really necessary ones..
This thread was just to find out if a pro built frame might be a realistic shortcut so I can focus on the novel parts of the project.
 
Bill I’ve been making backpacking and camping gear all my life.
I don’t start a project to save money, it’s about putting my ideals into form and enjoyment.
It’s how I’m wired- I like to build things.
The last thing I worry about is resale value.
That covers a LOT of us. Just not all the same interests.

I might not have the time for the project which would be a shame but that is the only limitation.
Too many projects- sometimes the really enjoyable ones are pushed aside for the really necessary ones..
"We" see enough glimpses of your activity, that it is probable time is the limitation, yes.

That said..

This thread was just to find out if a pro built frame might be a realistic shortcut so I can focus on the novel parts of the project.

.. so long as you have a pro welder on it, the "chassis", even DIY, will probably NOT be the part that soaks up the most time. Nor even money.
 
We build a few trailers here, mostly big, and more for each bossman boat trailers than should be allowed. AL has a tendency to have a low life span with metal fatigue, aka work hardening with road vibrations. Steel tubing hot dipped after building has never failed. Well vented and leaving weep holes in frame will last a good while. You can even paint over the zinc if you do it within the cure time of the zinc. Galvanizer will have it, I think it is less than a week.
Suspension is the fun design, we have not gone into independent yet - minus a transformer trailer/crane/crab thing once. Shocks are not optional if you want to be kind to the load. The frames are really not hard to build.
 








 
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