Bolt-together fiberglass Jeep-tub trailer kit

[jscherb]

I'm not understanding how you will mate your adjustable side panels, to the end caps.
do you have a more detailed illistration?

The side panels themselves aren't adjustable... the side panels will be molded at whatever fixed length is necessary for the trailer tub that is being built. What's "adjustable" is the position of a dam in the mold that defines the length of the side panel to be molded.

Here's a photo from my previous project to explain. This is the mold for the side window panel of the Safari Cab hardtop. The panel is roughly 52" long for the LJ. The side window panel for a TJ Safari Cab needs to be 15" shorter than the LJ part, so I've clamped a dam in place 15" from one end of the mold. The TJ part can now be made in the same mold that makes the LJ part, but because the fiberglass is laid up in the right side of the mold up to the dam on the left, the part will be 15" shorter.

So how will the side panels be attached to the end panels? They will be done in the same way the Safari Cab hardtop panels assemble - with a 90 degree bolt flange on the end of each part. Here's another photo from the Safari Cab project, showing how the side window panel bolts to the rear corner panel of the hardtop. This isn't a great photo of the bolt flanges, but you can get the idea from these unfinished Safari Cab panels:

When assembling a trailer tub, the panels will best be assembled with a combination of bolts and either structural adhesive, epoxy or polyester resin+a small strip of fiberglass mat. They could of course just be assembled with only bolts - however disassembly is an important feature of the Safari Cab hardtop but is probably not an important feature of the trailer tub, so adhesive will be a good idea.

BTW the joint between the side panel and the end panel in a factory Jeep tub is identical - the use 90 degree flanges, the differences of course are that the factory parts are sheet metal, and instead of bolts, the flanges are secured together with spot welds.

 

[Zeep]

Now I understand. I thought that the side panels would all come in one size, then cut to the desired lenth.
Looks like another awesome idea. I've followed your other posts here, and on other forums. Seems this one will also have several thousand posts!

 

[bluejeep]

"The trailer comes as two 4x4 foot frames bolted together in the center"

How clever of those Harbor Freight folks.

Disclaimer - The following thoughts are made without knowing the strength of the trailer, nor of the tub once it's attached. I did however, own a Northern Tool trailer in the 40" x 48" version, and the materials / design / construction look very similer to the pic in your post.

Considering the potential use (some might call it 'abuse') this trailer might encounter
-pounding from washboard roads for miles on end
-twisty situations over large washout areas or sidehills or pulling over boulders
-loads on top, such as a roof top tent
with ensueing side, fatique and torqueing loads, is there any need to make use of the back 4' of frame to provide additional strength to the forward 4 feet of frame?

Additional disclaimers
- I hate to waste material that's already paid for - sorry, I'm a cheapskate.
- The twisting will most likely not be anything to worry about because this unit is not prohibited from being able to rotate assuming the hitch allows this movement.

Strengthing by doubling such as
-bolting one on top of the other - (easiest of the following scenarios to do, but creates a frame 2 times the original height - don't know if that's an issue)
-bolting each matching frame member back to back, (again, not to difficult to do, and retains the original height of the frame, but does not provide a flat outer surface to fasten to- don't know if that's an issue)
-or nesting them to form a shape similar to a 'box' frame -albiet the flanges of one would not nest inside the other, but rather overlap on top of the corresponding flange of the other. (creates issues at points the frame members join together, and most likely goes beyond the 'drill job' concept.)

Assuming the tub will fasten directly to the frame and not 'float' separated from the frame, stress would transfer into the tub. I'm thinking the more 'stiff' the frame is to resist both flexing of the frame members as well as the twisting/torqueing forces, the less chance any stress spider cracking would occur in the beautiful fiberglassing coming out of your shop.
:coffeedrink:

PS - I know the resale value of your prototype would be much enhanced if it were to be painted in the dark blue that Jeep used on their 1997 TJ. Just saying. :wings:

 

[jscherb]

"The trailer comes as two 4x4 foot frames bolted together in the center".

How clever of those Harbor Freight folks.

Disclaimer - The following thoughts are made without knowing the strength of the trailer, nor of the tub once it's attached. I did however, own a Northern Tool trailer in the 40" x 48" version, and the materials / design / construction look very similer to the pic in your post.

Considering the potential use (some might call it 'abuse') this trailer might encounter
-pounding from washboard roads for miles on end
-twisty situations over large washout areas or sidehills or pulling over boulders
-loads on top, such as a roof top tent...

There's probably a limit to the abuse you'd want to put the HF frame to, once I've gotten their Heavy Duty trailer in my hands and I've assembled it I'll post my thoughts on its strength.

The ideas you posted (and I've omitted here in the interest of space), are good ones for reinforcing the HF frame.

I suspect many people would want to build a stronger frame than the HF if they're going to subject their trailer to off-road use more intense than gravel roads.

I do know that lots of people just want an on-road trailer for trips because the TJ especially has so little cargo space, so for them the HF frame would be perfect and very affordable.

Hey who knows, if these tubs come to market maybe the company marketing them would also offer a heavier-duty off-road frame kit...

PS - I know the resale value of your prototype would be much enhanced if it were to be painted in the dark blue that Jeep used on their 1997 TJ. Just saying. :wings:

I'm not sure if I'll leave the parts in gelcoat, or if I'll prime or even fully paint the tub. We'll discuss colors when I get to that point in the build of the proof-of-concept trailer (BTW I've got leftover black from painting my Safari Cab hardtop, and leftover yellow from painting my other trailer)

 

[demonslaer]

Definitely interested I would do one myself . but I don't have a space to do it . I worked in a fiberglass shop in jacksonville Fl making molds for jet boats and bushwacker tops for pickups. Keep us updated on your project the small one is what I'm looking for.

 

[Black Dog]

I think I might strongly consider this trailer when it becomes available.

I do have one idea that would improve on it. The trailer is a little shallow, it matches the depth of a jeep tub but it would be nice to have higher sides. So maybe some sort of an optional aluminum railing that would raise the height of the sides a bit would be nice.

 

[jscherb]

I think I might strongly consider this trailer when it becomes available.

I do have one idea that would improve on it. The trailer is a little shallow, it matches the depth of a jeep tub but it would be nice to have higher sides. So maybe some sort of an optional aluminum railing that would raise the height of the sides a bit would be nice.

I've had two thoughts on ways to raise the sides:

1. I'm considering doing optional stake pockets on the inside of the tub; you could use those to mount side boards to raise the height of the sides.

2. Riser panels could easily be made by using just the top 6" (or whatever) of the side and end panel molds - these would bolt to the top of the normal tub sides, and raise the edge by whatever height they were made to be. They'd match the style of the tub, and accessories, like tonneau covers, would still fit on the top edge of them because that top edge would be the same as the top edge of the tub (because it came from the same mold). The only drawback is you might want a taller tailgate too.

 

[joesjk]

Very interested. Ill be keeping my eye on this.

joe

 

[jscherb]

I got a PM this afternoon with a question about M416 military trailers. Since others might be interested, I'll answer it here instead of privately.

If your proposed trailer tub will fit a M416 frame, then I may be interested in buying one sooner rather than later.

There are a lot of M416, and similar variants, trailers out there. Mine, for example, is from 1949. While it's in great shape, it's now in need of significant metal work. There are many others in my situation.

Sierra trailers offers a replacement metal tub for ~$1,500, and to the best of my knowledge, that's the only option available.

So there is some form of existing market looking for a cheaper bolt-on alternative, but the dimensions would have to be similar. From the pictures you posted, your tub height looks short.

When I was shopping for a trailer years ago, I came across every variant of the M416 you could imagine. There was one civilian version that had a shorter bed height compared to the standard M416. Your trailer looks identical to that one. If you find the time, can you post your bed dimensions compared to a M416? Here's a good drawing with M416 specs: http://forum.ih8mud.com/trailer-tech/151174-m416-dimensions-specs.html

I haven't specifically designed the tub to fit the M416 frame, but I dropped a drawing of a 6' version of the tub on a same-scale drawing of the M416, and here's the result:

I don't know anything about the M416 frame, so I can't give a conclusive answer, but the drawing would suggest that the fiberglass tub may be able to be adapted to the M416 frame.

 

[jscherb]

Yesterday I picked up the HF trailer kit I plan to use under my proof-of-concept tub, and while I'm not planning to assemble the trailer frame until after I've got the fiberglass tub parts made, but I laid it out on the worktable today in the 4'x4' configuration I'm planning just to make sure all the parts are there (they weren't).

Since I'm shortening the 4'x8' frame to 4'x4', and not using the rear 4'x4' section, I had some extra crossmembers, so I'll use them as shown below, numbered 1 and 2:

Some of the changes I'll make while converting it from a 4'x8' to a 4'x4':

1. Add two extra crossmembers for strength and stiffness.

2. Use another one of the leftover crossmembers to become a third member of the tongue and also lengthen the tongue about 8".

3. Add a receiver tube. The receiver will enable bike carriers and other receiver-based accessories to be used on the back of the trailer.

All of the changes listed above are "drill and bolt" changes, things pretty much anyone would be able to do. That's my goal for this project - no special tools like welders should be required in order to assemble everything. I'll cover the changes in lots of detail when I get to the trailer frame assembly stage of this project.

The axle compares favorably to the 2000-lb. tube axles you can buy at Tractor Supply and Northern Tool; it's much sturdier than the c-channel axles found on the lower-capacity HF 4' and 4'x8' trailers.

I'm putting all the frame parts away for now, I need the worktable to do the fiberglass work on the molds and the tub parts.

 

[wjeeper]

I think your concept is sound enough. When cash for clunkers was in action I cant count the times I thought of buying two tubs and stitching them together, but then reality stepped in. I ah HORRIBLE at welding sheet metal!

Two things I really like:
1. I like the concept of the tailgates on both ends. Hauling a canoe, lumber, tube, etc would be really easy with this arrangement. Also if you loaded it up with gear it gives you two really nice access points without needing to take off the cover. I think this would make a good dual purpose trailer.

2. I LOVE the idea of the 5'X4" tub trailer. The width of a medium Camping Labs RTT is really close to the width of a Jeep tub and the lenght (when folded) just under 4'............I like the idea of making the 5'x4' tub into a DIY tentrax-esque set up.

If the price of the Bare tub was reasonable I would consider buying one and attempting option 2.........you would have my full attention.

 

[wjeeper]

Ok one post and I am done for the night.....

I really like that the tub is a modular approach. Your choice of one tailgate, two, or none and a choice in length.

Honestly I think the wheel wells are nice touch You don't have to sacrifice all the cargo area like you would if you welded two YJ tubs together. I also think that as long as the fiberglass wheel wells were a decent size you could get away with just one option.......I care to venture that anything that will fit under a stock wheel well will work for 95%+ of DIY guys.

Also building it so that it fits a HF trailer is not a drawback in my eyes. It should be super simple for a DIY guy/ welding shop/ trailer company to make a frame that would be more trail worthy. 4' width is standard throughout the trailer industry. No custom width/ perch axles needed, off the shelf units that any trailer supply shop would have would work with a frame of such dimensions.

 

[jscherb]

I think your concept is sound enough. When cash for clunkers was in action I cant count the times I thought of buying two tubs and stitching them together, but then reality stepped in. I ah HORRIBLE at welding sheet metal!

That was a big part of the inspiration for this project. After doing all the work to weld together two tubs, remove the inner fenders, etc., to make the yellow trailer, the idea of this "bolt together" fiberglass tub was born... there had to be an easier way

Two things I really like:
1. I like the concept of the tailgates on both ends. Hauling a canoe, lumber, tube, etc would be really easy with this arrangement. Also if you loaded it up with gear it gives you two really nice access points without needing to take off the cover. I think this would make a good dual purpose trailer.

Having two tailgates is really handy. Here's a photo showing a 16' extension latter in my 7' 5" trailer:

2. I LOVE the idea of the 5'X4" tub trailer. The width of a medium Camping Labs RTT is really close to the width of a Jeep tub and the lenght (when folded) just under 4'............I like the idea of making the 5'x4' tub into a DIY tentrax-esque set up.

Not being a camper myself, I'm hoping for plenty of input from you guys to help me finalize the design of the flip-top tent platform option.

If the price of the Bare tub was reasonable I would consider buying one and attempting option 2.........you would have my full attention.

 

[jscherb]

When I get to the stage of assembling the frame and putting the tub on the frame, I've got a good range of wheel and tire combinations to experiment with, I've got a pair of each of these sizes to try:

Left to right - 22" tire on 12" rim (came with the HF trailer frame), 26" tire on 14" rim (found this pair on the side of the road, someone put them out for trash), 30" tire on 15" rim (what I've been running on the yellow trailer), 32" tire on 16" rim (matches what I've got on the Retro Wrangler pickup). I'll also check the junkyard for a pair of 28" tires on factory Jeep steel rims to round out the collection, I think those would be a popular and inexpensive option for the trailer so I'd like to try them too.

I'd be interested in hearing what size tire people think should be on the 4'x4' proof-of-concept trailer I'm building. For a budget on-road version, the 12" wheels that come with the HF trailer might be fine (maybe would build assemble the tub with smaller wheel wells for that configuration), and for off-road use I'm thinking 15" wheels, maybe 225-15 or maybe up to 30x9.50? Since the trailer has more clearance than a Jeep (no diff or transmission skid plate hanging down), a 225-15 on the trailer probably has as much ground clearance as a 33 on the Jeep... I'll have to measure that to confirm.

 

[jscherb]

Ok one post and I am done for the night.....

I really like that the tub is a modular approach. Your choice of one tailgate, two, or none and a choice in length.

Honestly I think the wheel wells are nice touch You don't have to sacrifice all the cargo area like you would if you welded two YJ tubs together. I also think that as long as the fiberglass wheel wells were a decent size you could get away with just one option.......I care to venture that anything that will fit under a stock wheel well will work for 95%+ of DIY guys.

The main reason I was thinking of having different sized inner wheel wells be available would be to maximize interior space. If you're building the tub to fit on a trailer a wider track like I did with the yellow trailer, then the inner fenders can be narrower than if you're building with the same track width as the Jeep. And if you're building to use one of the HF frames and plan to use the stock 12" wheels, then the inner fender can be really small, providing for that much more interior space. But if people don't think that option is worth doing for the kits, then maybe I won't do it.

Also building it so that it fits a HF trailer is not a drawback in my eyes. It should be super simple for a DIY guy/ welding shop/ trailer company to make a frame that would be more trail worthy. 4' width is standard throughout the trailer industry. No custom width/ perch axles needed, off the shelf units that any trailer supply shop would have would work with a frame of such dimensions.

Those are exactly my thoughts. HF trailers will be right for some people; others will want to/need to take a different approach.