Bending Aluminium I Beam for Trailer, How i done it! manufacturers will go broke

[Chilly 07]

Hi,Apoligises if this is already stated...have not read all. This article might be of interest:
https://www.thefabricator.com/articl...-6061-aluminum

A copy of a section of this link:
Consider aluminum 6061-T6. Here the alloy is 6061 and the temper is T6, meaning the alloy has been thermally treated.
Material suppliers have tables that show the approximate minimum inside bend radius for the various alloys, the temper condition of each, and the minimum allowable inside radius at 90 degrees of bend angle. (For one example, check out the chart, “Approximate Minimum Radii for 90° Cold Bend,” available at http://www.aircraftspruce.com/pdf/20...l/Cat16057.pdf.)
Forcing a radius to less than the recommended minimum may cause the final part to fail in service and may void any warranties or guarantees issued by the material supplier.

Hope this helps

[Darren J]

I have a us made alloy trailer, from memory the I beams are 165 high. They are 6061t6. The manufacture was in conjunction with a Melbourne builder mentioned above. They advised that the only i beams that can be bent without distorting are 6061. It was about 4 years back, but at the time higher volume Aussie builders were getting into alloy as a lot more common option, and it was mentioned that not having access to the k beam sizes locally on 6061 was a. It if an issue, as the available other grades distorted badly on the flanges.

Again I was looking at heavier sections for a bigger trailer, but I took out of this that 6061 is the stuff to use. All sections on the trailer were actually in that grade, again not readily available over here. My trailer is about 9m long, but the A frame is long with fairly gentle bends. I will measure the angle if I get the chance.

[gazza2006au]

Thanks Chilly but they don't state the length of the bends to say the thickness of the material being bent

[fishtragic]

Gazza, Sorry if I'm stating the obvious but if you've got no stress marks/cracking at 16 deg. why not do two bends to achieve your angle. I did the I - beam thing but got an engineering shop to do the bends, $300. I didn't want the risk of getting it wrong myself. The saving on DIY as opposed to buying new was 7 - 8 grand. I wouldn't be welding the angles.
Mark

[gazza2006au]

Hey Mark, I emailed a fair few shops and only a couple got back to me and said they won't touch 6061 T6 alloy

[TREVELLY]

A home made trailer and snapped across the draw-bar due to stiff suspension on the back of his small truck going to 1770 a couple of months ago - the trailer and boat went scrub - luckily not hitting another vehicle etc.
The insurance company wiped their hands on is claim as the trailer wasn't manufactured by a certified manufacturer/welder etc with QA etc etc.
I would bet money if it had run into another car and killed someone he would be in goal right now.
Not trying to rain on anyone's parade - just saying - be aware and be careful
Too many things are learnt by accident and I try and learn from other people's accidents

[gazza2006au]

did a home made trailer and it snapped across the draw-bar due to stiff suspension on the back of his small truck going to 1770 a couple of months ago - the trailer and boat went scrub - luckily not hitting another vehicle etc.
The insurance company wiped their hands on is claim as the trailer wasn't manufactured by a certified manufacturer/welder etc with QA etc etc.
I would bet money if it had run into another car and killed someone he would be in goal right now.
Not trying to rain on anyone's parade - just saying - be aware and be careful
Too many things are learnt by accident and I try and learn from other people's accidents

Isn't 1770 corrugated roads? You also mentioned welds and a aluminium trailer?

[Noelm]

No, sealed road all the way.

[gazza2006au]

I wonder if the draw bar was aluminium? mine will be steel

[TREVELLY]

His trailer was steel guys - the point is the insurance companies will look for any way to get out of paying and any lawyer will look for any grounds to blame in the event of an accident

[gazza2006au]

Trev i think we are missing a big portion of information here, picture of the rig please, what size steel were used, what size boat, alloy or glass, lots of factors in this situation

obviously a weld broke? because u say the welder was not certified that raises concern was the welder even capable of making suck welds this is why i am not going down the steel trailer route

an aluminium trailer is all bolt together there is no rocket science behind it there is also only welding on the safety chain and spring hangers which can be done by a qualified welder for $100-$150

[ozscott]

I like the idea of alloy but will stick with steel, especially for corrugated roads. They dont like the stress of welds and they tend to work harder around bolts. Not saying it cant be done...lot for a home designer though depending on size. My BIL is an experienced mech engineer and not bad with a welder. His work purchased 2 trailers from different manufacturers ...bolted alloy for a bobcat. Both started failing after a short time around the bolts. He went touch one for a boat. Steel is just so much harder to get wrong if you use good.steel. I think the yanks have bee. doing alloy trailers for longer and probably have them largely sorted but again for corrugated roads they wouldn't be my choice.

Cheers

Sent from my SM-G960F using Tapatalk

[gazza2006au]

I like the idea of alloy but will stick with steel, especially for corrugated roads. They dont like the stress of welds and they tend to work harder around bolts. Not saying it cant be done...lot for a home designer though depending on size. My BIL is an experienced mech engineer and not bad with a welder. His work purchased 2 trailers from different manufacturers ...bolted alloy for a bobcat. Both started failing after a short time around the bolts. He went touch one for a boat. Steel is just so much harder to get wrong if you use good.steel. I think the yanks have bee. doing alloy trailers for longer and probably have them largely sorted but again for corrugated roads they wouldn't be my choice.

Cheers

Sent from my SM-G960F using Tapatalk

Totally agree alloy isnt or corrugated roads unless u could possibly run large bolts like 30-35mm bolts as the larger hole would distribute the forces a lot better than what looks to be 12-14mm bolts on some of the commercial trailer builds but the flanges don't allow the bigger bolts on smaller trailers

i have been down a few corrugated roads and i drive a small 4x4 and at times i think the steering is going to fall out from under the car at 50-60kph

for me i am a burbs blokes so its all high way and motorways

a few of the aluminium boat manufacturers mention on there web sites what alloy they are using 6061 T6 and its likely from China, I'm unsure where Capral gets there aluminium extrusions from hopefully it isn't China but going by there prices it may be locally made or imported from the USA or something as a guess

actually the aluminium Capral sells is 6082 T6 which is from my understanding harder than 6061 T6 so it should be a tougher trailer build

on aside note if anyone building there own trailers has a worry u can always run safety chains across cross members or along sections of the aluminium u may think could be a weak link in the design but i reckon just over engineer it from the beginning

[TREVELLY]

Any trailer that is home made without QA certs will be more than likely be a declined claim by insurance company whether it fails at a weld or not.
You can always contest it if you can afford to do so
I hear what you are saying about getting proper bods to do welding but also just make sure any work you are doing including bending the aluminium is something that doesn't require qualified dudes - I am a little uneasy about having the aluminium treated to bend it or risk micro cracking - just my thoughts
Wishing you all the best with it though Gazz - a great project.
BTW thanks for fixing up earlier post
Also as a fyi I have a Dunbier aluminium trailer and I do like it
http://www.ausfish.com.au/vforum/sho...hlight=Dunbier

[brett62]

[QUOTE=TREVELLY;1646886]Any trailer that is home made without QA certs will be more than likely be a declined claim by insurance company whether it fails at a weld or not.
You can always contest it if you can afford to do so

It doesn't matter who builds the trailer, Home builder or manufactured by a name brand it is required to meet ADR and as Trevelly said your insurance company could question the roadworthiness. It's the same if they inspect the trailer for a claim and it's rusted and not maintained to a roadworthy condition you lose again.

If you are building your own trailer you must comply with ADR and it's your responsibility to insure this is the case. When you have your machinery inspection for your registration just because the inspector passes your trailer he is not passing the design and strength. This part is all on the builder of the trailer.

I have built both steel and aluminum trailers when I was boat building (aluminum) and also repaired many trailers over my time. If you are towing long distances and over some crappy roads you are best with steel they just rust away over time. Aluminum trailers are great for keeping the weight down if you have a towing capacity problem. These days there is not much difference in the price between the two where years ago the aluminum trailer was very expensive. This was my own business and all my personnel boats I had on steel trailers so that should tell you my preference.

Anyway gazza just build it like a brick shithouse as you are doing with the boat and you won't have any problems.

PS. when we bend aluminium plate/sections we do it under control heating and annealing. To much heat and you will compromise the gain structure and this is something you won't see with your eye's.