Welding Tips and Tricks

Was going to build my own 6'x10' utility trailer. My question is the plans call for 2x2 3/16 angle iron. I was wondering if I wanted to use aluminum how can I do a conversion to find out what size Al to use that would match the strength of the steel?

Times 3 rule of thumb for 1/2 the weight saving.
Math engineer will be more exact I am sure.

"Times 3 rule"... meaning he'd use 3/16 x 3, or 9/16 aluminum 2x2 angle?

Not challenging your statement, looking to learn.

I am not a pro by any means but that doesn't seem correct, 9/16" aluminum? how many trailers have you seen with 9/16" aluminum rails. I looked at the specs and it's not specific to thickness but 6063 Al has tensile strength about 40-50ksi and A36 steel is like 70-80ksi.

pavetim wrote:I am not a pro by any means but that doesn't seem correct, 9/16" aluminum? how many trailers have you seen with 9/16" aluminum rails. I looked at the specs and it's not specific to thickness but 6063 Al has tensile strength about 40-50ksi and A36 steel is like 70-80ksi.

I believe he was doing the "times 3" rule (3/16" x 3) someone else posted. Actually Al angle isn't available in 9/16" thickness

rick9345 wrote:Times 3 rule of thumb for 1/2 the weight saving.
Math engineer will be more exact I am sure.

didn't think some one would take it literally.
3/16 times 3, 9/16 or more to point closest available ,in this case 1/2". I am not a math whiz engineer.error on the side of strength/safety.

I am not a trailer builder or a metallurgist but I know for a fact a 6x10 utility trailer doesn't need 1/2 thick aluminum angle. Wish some trailer builders would chime in here. 1/2 thick aluminum is just crazy it would cost $5000 to build a $1500 trailer

Building a trailer or structure is often more about support and bracing. And using the properly shaped metal i.e. Square tube, angle, channel, round, or some type of h beam. To give suport where it's needed.

pavetim wrote:I am not a trailer builder or a metallurgist but I know for a fact a 6x10 utility trailer doesn't need 1/2 thick aluminum angle. Wish some trailer builders would chime in here. 1/2 thick aluminum is just crazy it would cost $5000 to build a $1500 trailer

I build trailers. Is there a reason why you want to do it in aluminum? The aluminum trailers I see don't have thicker metal components, just more of them. Overbuilt is what I call it to compare strength of steel. A 6x10 is not a big trailer so aluminum is not going to save you much weight when considering the dramatically increased cost to build it. You have to use bolts on certain things such as shackles and the tongue to trailer connection where welds can't be trusted anyway so I don't see any advantages to aluminum in a trailer unless its a boat trailer or a horse trailer other than aluminum welding practice. If you have money burning a hole in your pocket and really want to do it in aluminum then switch frame components to C-channel and you can keep your railing in angle. The best advice I could give you is go to a place where they sell trailers and look at how a manufactured aluminum trailer is built( to DOT standards) and copy it. Aluminum has its advantages bit IMO not in a simple utility trailer. Aluminum trailers are pretty when they are new but after weathering and wear and tear, they look as crappy as anything else and aluminum welds break, I know because I fix them all the time.

Cause I tow it behind a 5th wheel trailer and I want to keep the weight down as much as possible. I towed a 5x8 no problem but I want to build a 6x10 so want to keep the weight down. Most likely due to cost i'll probably build it out of steel but if i can get a deal on Al i'll build it from that.

exnailpounder is right, don't need 1/2 alum. 3 times is still 3 times--- more braces or channel or what ever, just need to think one needs more volume of material to equal the strength of the steel. shapes also influences the strength. sq tube versus angle the shape will describe an enclosed volume.
This was not meant to be a how to, or expert opinion, it was encourage those to explore possibilities. can the switch from steel to alum be done? sure it can,but it will take some research.

pavetim wrote:Cause I tow it behind a 5th wheel trailer and I want to keep the weight down as much as possible. I towed a 5x8 no problem but I want to build a 6x10 so want to keep the weight down. Most likely due to cost i'll probably build it out of steel but if i can get a deal on Al i'll build it from that.

The difference between a 5x8 and a 6x10 is probably not more than 100lbs. You can lighten up the decking by using 5/4 instead of 2" material. There are a few ways to cut weight on a trailer. Different metal shapes are stronger than others and you may be able to use a different shape in a thinner material or change your design a little.

The material my plans call for is 3/16", L-angle. What would be stronger but that I can go thinner? C-channel?

pavetim wrote:The material my plans call for is 3/16", L-angle. What would be stronger but that I can go thinner? C-channel?

C channel is good. Don't know what the difference in weight would be though.

I built my trailer 7X10 out of 2X3X.078 square tubing. I spaced the cross bracing on 24" centers. I used 2X2 square tubing for a rail about 4" above the deck. I used 14 Gauge steel plate for the decking. I also have a 4' drop gate on the rear. It is light weight and has held up well. It was never intended to haul anything more than a couple of ATV's or our SXS.