Aluminum trailer frames and other wild ideas.

[TD Beej]

I've long wanted to build a Teardrop and have been playing with some ideas. At this point it is a bit of an intellectual exercise but maybe I can get a few of these other projects out of the way.

First among these is using aluminum instead of steal for the frame, taking into account for electrolytic reactions between such things as the axle and tongue would there be any other considerations I would need to consider?

I am also thinking of building a skeleton out of aluminum and then making insulated core walls possibly doing the whole thing in fiberglass if I go with a more rounded shape.

Since one of my concerns is high speed stability and chuck around corners I am wondering about the effectiveness of:
- Dual axles with smaller wheels.
- Ground effect skirts with air diffuser.
- Antilock brakes.
- Anything else anyone can think of???

Thanks!
Beej

[doug hodder]

TD Beej....It's interesting that you posted this inquiry. I was just about to post one to mig/tig welders about an aluminum cabin. You're way ahead of me if you are thinking about ground effects however. I was just thinking about weight. not towing it with a Ferrari. I think that smaller wheels may not be the way to go as with speed they are doing a lot more work, and would have an increased chance of bearing failure, and if it is lighter why bother with antilock brakes?, or any for that matter. I guess it just depends on what you are towing it with. Great thought process though, that's what is going to develop these trailers, and in the words of Robert Redford in Butch Cassidy and the Sundance Kid, "you keep thinkin' Butch, that's what yer good at!" doug hodder

[OkieSailor]

Strange you should come up with this subject. I just cut and fitted 1inch by 2 inch wide c-channel to the wooden base of the teardrop I am building. I am going to use steel for the tongue and tongue connections. The rest of the frame except for the axle and springs will be aluminum. I have used 9 3inch 1/4 20 SS phillips head (so they will go flush) per long side to tie the wood base to the aluminum c-channel. $47 for a 25ft piece at the local metal supplier. Boy I hope I am not messing up big time!!

Am still looking for information on making all plexiglass 1/4 thick doors and need information on some of the sliding windows with screens I have seen. Any help would be appreciated.

And Yes OkieSailor is an oxymoron!!

[TD Beej]

Hi Doug,

You asked why to a few things well...
- Dual axles and smaller wheels to get lower improve ride improve roadholding.
- Ground effects and Diffuser to keep the trailer behind me in the twisties.
- ABS for two reasons, one in an emergency situation to keep the trailer behind me and because don't want the trailer to push the backend of the out in braking on a bend.

PS
No tIalian cars but the "vintage" BMWs are really kind of pointless on the fun roads with a trailer unless the trailer behaves well.

Thanks,
Beej[quote][/quote]

[doug hodder]

Hey Okie. plexiglass doors? Poly would be the way to go, it is more flexible, but is 30 times more impact resistant than plex, do you plan on overlaying it onto anything?, or getting 1/2 inch material. Plex can shatter, but I've seen signs with poly that have had 38cal. slugs put through them and they don't bust. doug hodder

[doug hodder]

Beej....I apologize, we are in different worlds. I don't need to worry about handling behind my pickup, but I can understand your needs. A super handling trailer would be awesome, however, I think that the spindle/bearing area would be something you would like to think through. whether it is go fast or corner, the bearings and spindles need to be able to handle the load. I'm sure it can be done with no problem, I'm not the person to give you expertise on it though, but when you get it all done, please show us the results. here's another wild thought. check out any of the pre-mix trucks in the area. Some have drop down tag axles that follow the steering of the truck, to meet DOT specs. I don't know how they officially work, but it would give you a trailer that followed the towing vehicle dead on. It would be a trick set up though. doug hodder

[TD Beej]

Hi OkieSailor,

Did you do anything to isolate the soft steal from the aluminum pieces? The Stainless and aluminum should be fine together.

Beej

[D. Tillery]

You will have to bolt the steel axles and hitch coupler to the aluminum. I would just paint or powder coat the steel first and not worry about oxidation. You can TIG your frame together or run aluminum wire through your MIG with straight Argon. Flux core aluminum wire and stick electrodes are also available but very expensive. With the price of steel so high right now, aluminum is very attractive. I've been designing and planning on going the all-aluminum route too. Possibly the only completely wood free tear around.

D. Tillery

[angib]

To prevent electrolytic corrosion in a marine (and aeronautical, and military) environment, there is an anti-corrosive jointing compound called Duralac. As far as I can tell, most of Europe uses this. It is not cheap (maybe $15 for a toothpaste tube quantity) but it does work - we used to use this to put stainless hardware into/onto aluminium and never had any electrolytic corrosion in the presence of sea water (a demanding test!).

Searching to see if it is available in the USA, I came across this list of suitable compounds specified by a New Zealand propeller company (and the aeros always take their corrosion prevention pretty seriously):

"In order to prevent corrosion, and facilitate future disassembly, some components should be assembled with an anti-corrosive jointing compound. Such compounds are sometimes called anti-fret compounds or anti-seize compounds. Suitable compounds include:
• PRC-DeSoto: CA1000.
• PRC-DeSoto: JC5A.
• Kluber Lubrication: Kluberpaste 46 MR 401.
• Llewelyn Ryland Ltd: Duralac.
• Loctite: Zinc Anti-Seize."

Please note I cannot say if these other compounds offer the same level of corrosion protection.

Andrew

[Mark Mckeeman]

This is a bit long winded but may help some folks out.

In the fall I did a comparison between steel and aluminum frame costs for a 10’ Cubby for a friend of mine. I spoke to another buddy who runs a welding shop and has built many trailers over the years. He has the first all aluminum utility trailer I ever saw and he built it himself because no one was doing it commercially yet. I asked him about material thicknesses required and he gave me his general fabricators rule of thumb.

“When switching from steel to aluminum use the same external dimension material and increase the wall thickness accordingly, usually the next fractional size”

The steel frame my buddy wanted was to be made from 2X3 1/8 wall tube. I think this is different than the plan called for but that’s what he wanted. The question we tried to answer was how much weight could be saved and at what cost. We used the local metal suppliers price list and weight per foot of material to make our comparison.

In general terms this is the result. An aluminum frame made from 2x3x3/16 Aluminum tube would weigh half as much as a steel frame made from 2x3x1/8 material, however the aluminum was four times more expensive per pound, (steel 1$lb AL 4$lb) therefore the trailer would cost twice as much.

Given that the cost and weight of the axle, wheels, hitch, stabilizers and lights would be the same the benefit of an aluminum frame was further reduced. If you were paying for the fabrication I expect that those cost would be similar. You may pay a premium though if you wanted the frame TIG welded.

Now building the frame out of 2x2x1/8 steel, which seams to be an acceptable norm as evidenced by this board was calculated the weight and cost advantage over aluminum would be negligible.

Now take the total cost of all this fabrication and compare that to the cost of an HF trailer or Snowbear and you find that building a trailer may not be worthwhile at all.

This paper work exercise helped my friend make some considered decisions about his teardrop project and may help others as well.

Mark

[asianflava]

Anti-sieze compounds have this great ability to get on everything. I use it frequently when working on cars, it's a throwback to my aviation days. No matter how careful I try to be, it just seems to get on everything

[D. Tillery]

I'm really interested in everyones concern with the possible corrosion betw/ SS and aluminum. Is this really a concern on a tear? Do other aluminum trailers use bushings or antiseize compounds? I have not seen this problem on boats under about 10 years old in coastal conditions. I don't think it is much of a problem. Someone convince me otherwise.

On aluminum fabrication: A fabricator will charge you about twice as much to work in aluminum in addition to the materials cost. The time, skill and equipment involved to do a good job in aluminum brings a premium. It is hard to justify financially building in aluminum. You just have to want to save the weight to use elsewhere, like SS skin, and open your wallet.

D. Tillery

[TonyCooper]

I'm really interested in everyones concern with the possible corrosion betw/ SS and aluminum. Is this really a concern on a tear? Do other aluminum trailers use bushings or antiseize compounds? I have not seen this problem on boats under about 10 years old in coastal conditions. I don't think it is much of a problem. Someone convince me otherwise.

I first raised the question after one of the teardrop parts suppliers recommended that I use some type of aluminum nail to secure the molding to the aluminum siding to avoid corrosion problems. I hadn't given it much thought prior to that. I had planned on (and will be) using SS screws.

[Woody]

I used stainless steel screws on my aluminum trim and was worried as well about electrogalvanic corrosion. I have not seen any evidence of any reaction what so ever in the humid salt air Florida enviroment my Teardrop stays in. I don't know what will happen down the road, for the most part I really don't think it is that big of a problem with having built mostly from wood (body). It might be more prevalent on metal body frame fabrication where there is more more connective electrical activity due to dissimiliar metals coming in contact with each other used in the build

[OkieSailor]

Mark's reply pretty much told me what I wanted to know. After checking prices of steel here against alumimun I chose the alumimum because of my daughters oriental rice burner pulling the trailer. Thanks for all the information. I do not think that any interaction between the SS and the alumimum will be a major problem.