Materials for a light weight chassis?

[HandyAtLeast]

I've never done any welding, but we have a gas TIG welder here at work and I'm going to try my hand at it. I plan on building a foamy trailer, which will be very light weight. I originally looked into and got quotes for 2"x2" steel tubing for the chassis, but I am wondering if that is overkill. I want to build a 5x8 trailer with some kind of torsion axel, either Dexter #8 or half axels.

Anyway, I'm thinking about building much of the chassis out of 2" angle, except the tongue, of course. Any thoughts on this? A local trailer building company gave me a quote of $800 for a 5x8 trailer with lights, but unpainted, made out of channel. They make all of their trailers out of channel because a big part of their business are boat trailers and channel has no areas to hold water and therefore rust.

Seems like angle, with the right number of cross-members, would be fine. Any thoughts?

[starleen2]

Seems like angle, with the right number of cross-members, would be fine. Any thoughts?

A TSC 4X8 no floor is constructed out of 2x2 angle - except for the tongue - it will be just fine

[HandyAtLeast]

Thanks, that's what I figured, but just wanted some feedback on it. I'm going to practice on some scrap and build a mini chassis to practice my welds. Should be fun.

[doug hodder]

Welding is a lot of fun, I enjoy it. Since it's a first time welding project for you and it's something that will be dragged down the freeway, in traffic....it might be a good idea to have someone with some background in welding to closely look at your design and final welds before you venture out. Just my opinion. Doug

[HandyAtLeast]

Yeah, well, doing it at work, I don't think I'll have any choice. The lame part is that I had a Dad that was a crack stick welder. He worked on his John Deer Cat, military surplus Power Wagon, 3 wheel coal scoop, saw mill, etc and I never got to learn a stitch from him. It was two ways: I didn't care enough at the time to express interest and he was old school do-it-yourself / don't talk about it. Oh, well. No time like th present.

[CARS]

TIG has a big learning curve. It is nothing like ARC or MIG where you can get away with some contaminants in the weld.

I would really like to see a beginner do a project like this with a MIG welder. It's kinda like spraying water out of a garden hose. Point and shoot. If it's set up right you'll get great penetration and strength. Almost fool proof. (and if you screw up MIG welding, you shouldn't even consider TIG welding IMHO)

With TIG you will have to make multiple passes over perfectly clean metal. Most anything over 1/16" thick is beveled with a minimum of 3 passes. A very time consuming weld process. Each time you stick your tungsten in the weld you have to stop and re-grind it. Feeding the rod with one hand and holding the tungsten off the weld with the other takes practice, practice, practice.

With that being said, if you have the time to practice for a couple weeks go for it!! Hopefully someone will be by your side so you don't learn any bad habits. Learn the proper technique and you'll be way ahead of un-learning bad welding habits.

[dh]

TIG has a big learning curve. It is nothing like ARC or MIG where you can get away with some contaminants in the weld.

I would really like to see a beginner do a project like this with a MIG welder. It's kinda like spraying water out of a garden hose. Point and shoot. If it's set up right you'll get great penetration and strength. Almost fool proof. (and if you screw up MIG welding, you shouldn't even consider TIG welding IMHO)

With TIG you will have to make multiple passes over perfectly clean metal. Most anything over 1/16" thick is beveled with a minimum of 3 passes. A very time consuming weld process. Each time you stick your tungsten in the weld you have to stop and re-grind it. Feeding the rod with one hand and holding the tungsten off the weld with the other takes practice, practice, practice.

With that being said, if you have the time to practice for a couple weeks go for it!! Hopefully someone will be by your side so you don't learn any bad habits. Learn the proper technique and you'll be way ahead of un-learning bad welding habits.

2nd that!!!

If you have experience welding with a gas torch, TIG isn't that big of a step either, but in this day who welds with a gas torch?

C-channel may or may not be the best choice for your frame. How are you attaching the walls? If you want to attach them to the frame, you will have to put the web on the outside, and cut a tongue on both sides of every X-member. If you don't attach to the frame rails and put the web on the inside, you have a nice recessed and protected area to put marker lights.

[dh]

One more thought on tig welding, welding vertical can get hairy for the beginner. Might be worth it to see if you could get a welder from work to weld it up for you for a case of beer.

[dh]

TIG has a big learning curve. It is nothing like ARC or MIG where you can get away with some contaminants in the weld.

I would really like to see a beginner do a project like this with a MIG welder. It's kinda like spraying water out of a garden hose. Point and shoot. If it's set up right you'll get great penetration and strength. Almost fool proof. (and if you screw up MIG welding, you shouldn't even consider TIG welding IMHO)

With TIG you will have to make multiple passes over perfectly clean metal. Most anything over 1/16" thick is beveled with a minimum of 3 passes. A very time consuming weld process. Each time you stick your tungsten in the weld you have to stop and re-grind it. Feeding the rod with one hand and holding the tungsten off the weld with the other takes practice, practice, practice.

With that being said, if you have the time to practice for a couple weeks go for it!! Hopefully someone will be by your side so you don't learn any bad habits. Learn the proper technique and you'll be way ahead of un-learning bad welding habits.

2nd that!!!

If you have experience welding with a gas torch, TIG isn't that big of a step either, but in this day who welds with a gas torch?

C-channel may or may not be the best choice for your frame. How are you attaching the walls? If you want to attach them to the frame, you will have to put the web on the outside, and cut a tongue on both sides of every X-member. If you don't attach to the frame rails and put the web on the inside, you have a nice recessed and protected area to put marker lights.

[HandyAtLeast]

Okay, point of clarification. I meant to say MIG welder, not TIG.

And here is what I was thinking for welding up the frame. I made it so the flange would be on the outside for ease of welding the cross members. It is all 2" angle and one 2" tube for the tongue. Might add some angle to make a-frame on the tongue. Or not.

[CARS]

Good. I taught my 11 year old to MIG weld. A little practice and you are golden!

[Artificer]

If you are thinking of using 2x2 1/8" angle, one thing to consider is 2x2 16ga box tube. About the same weight, (1.65lb/ft vs.1.711) but welding is simplified. My 4x8 trailer frame is only 60lbs. The trailing arms/spindle/tires doubled that.

One place I think you can save weight is to use steel ribs for the floor. I used 16ga steel and bent up some C-channel. Ended up about 3lbs each. 16" on center, and you only need 4. If I was going to do it again, I would go to 18ga. Less than 2.5lbs each, so 10lbs for a sturdy floor. I then used 1/4" plywood for the floor. My frame is an integral part of the floor.

One of the best things you can do to learn is to weld up some test pieces, like you would for your frame, and then break them apart. Did you get good penetration? Are there pinholes? How easy was it to break? One downside to a MIG welder is that you can have pretty welds that are not strong. Either chamfer the edges to ensure penetration, or practice until you know what a good weld feels like.

Michael