Welding layout for this piece I am building???

[1SlowFormula]

Hey all, I have an H shaped part that I want to make and with the legs of the H being about 6" on top side and about 8" on the bottom and the cross piece being only 2.25", so getting the gun in the right position is tough. I was thinking instead of trying to do 2 T joints with 3 plates, that I would use 2 pieces of channel and **** them together **** welding the exterior radius of the channel, grinding the sides down flat, then plating it and edge welding the sheet similar to this (green being the channel **** weld and the blue being the edge weld around the entire part, not drawn to scale, sorry):

Thoughts?

 

[readhead]

How long is it and does it have to be strong?

 

[1SlowFormula]

Yes it has to be strong, and it has to be stronger than the one that comes with the kit. It is a suspension bracket, the "manufacturer" of this kit uses 5 pieces of plate to make the H shape and only welds the outside and I don't want that on my truck, and don't really want to fix their method of building the piece either.

Here is a pic from a kit that costs about $1100, and I think I can build my own for cheeper without the flaws in craftsmanship. The left shot I circled where the 5 pieces of plate meet, but you can also see absolutly no welding done on the interior of the H, the second shot is a profile of the piece installed on some elses truck.

Mine would have longer legs on the top H and still guseted on the bottom, and welded to my frame instead of bolted.

 

[BD1]

That is just steel ? Nothing exotic is it ? Stick weld it. Looks like a perfect job for stick welding.

 

[1SlowFormula]

Nope just steel, nothing exotic, and I only have a mig welder and only done some mild stick welding many years ago.

 

[readhead]

Is it possible they got sent out without being welded? Did you ask the supplier? I would weld up what you have. Stick welding it like BD1 mentioned would work well.
I would think twice about welding to the frame. You could create a bunch of stress risers and have a whole new set of problems.

 

[dr_clyde]

I assume you've checked with all the local steel supply shops? No commercially available structural steel that you could trim to fit?

I would avoid welding the channels like you have shown. That's a lot of weld, and is asking for trouble.

You haven't mentioned wall thickness, but it looks like 1/4" or so. The 3 plate t joint is a better joint design. I would just do a nice 7018 stringer bead on each joint, if I had to make it. If you want to mig it, lay it in nice and hot. Spray transfer if possible, but failing that a nice hot short arc would suffice.

 

[PugetDude]

^^^this^^^

 

[1SlowFormula]

Yeah I trust my mig skills more than stick, since I use the mig a lot more often and would have to borrow a stick from a freind. As for wall thickness, the existing bracket is 3/8 steel, but the one I was planning on doing, that is sounds like you guys are against, was 3/16 in the U shaped channels and 3/16 plate cap and would have equal overall thickness. Plus I can form the 3/16 channels in my shop, I cannot bend the 3/8 myself, or at least never tried forming anything that thick, lol...

 

[ishiboo]

I would definitely bolt it to the frame and not weld to it.

 

[R.Anderson]

I would definitely bolt it to the frame and not weld to it.

2nd this.

 

[mechan]

I assume you've checked with all the local steel supply shops? No commercially available structural steel that you could trim to fit?

I would avoid welding the channels like you have shown. That's a lot of weld, and is asking for trouble.

You haven't mentioned wall thickness, but it looks like 1/4" or so. The 3 plate t joint is a better joint design. I would just do a nice 7018 stringer bead on each joint, if I had to make it. If you want to mig it, lay it in nice and hot. Spray transfer if possible, but failing that a nice hot short arc would suffice.

Short arc is prone to lack of proper penetration, so I would probably want to make sure I was getting CJP either via proper gaping or back gouging. One could look at the AWS D1.1 pre-qualified t joints to get an idea how to fit up your weldment.

Defiantly bolt the member to the frame, welding it doesn't make a ton of sense.

 

[dr_clyde]

Short arc is prone to lack of proper penetration, so I would probably want to make sure I was getting CJP either via proper gaping or back gouging. One could look at the AWS D1.1 pre-qualified t joints to get an idea how to fit up your weldment.

Defiantly bolt the member to the frame, welding it doesn't make a ton of sense.

Which is why I said my first two choices were stick and spray transfer wire... And now that I know he's doing 3/8"plate, I can't in good faith recommend a single pass of short arc.

 

[R.Anderson]

Which is why I said my first two choices were stick and spray transfer wire... And now that I know he's doing 3/8"plate, I can't in good faith recommend a single pass of short arc.

Spray transfer would be great but you need the proper setup for it and the know how. I kinda betting 1SlowFormula may not have the setup for it. You need shielding gas that contains no more than 15% co2 such as 90/10, your standard 75/25 will not allow spray transfer. Running 100% co2 gets you deeper penetration than 75/25 but enough I don't know depends on your MIG welder if you can weld 3/8" plate with it or not. Best bet stick it

If your MIG welder is large enough you can get flux core that runs with shielding gas that gets ya deep penetration but the wire is not cheap.

Also with spray you can only weld flat and horizontal unless you pulse spray then its game on.

 

[1SlowFormula]

Yeah my welder is rated at 3/8" with a single pass, but I only have 75/25 mix gas. Anyhow, it sounds like my best bet is to practice with a stick welder for a bit then just stick weld it.

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[1953mercury]

This seems like it is being way over thought. It's mild steel, you have a mig welder of sufficient size, weld it. Mike

 

[mechan]

This seems like it is being way over thought. It's mild steel, you have a mig welder of sufficient size, weld it. Mike

Agreed. Just multiple passes and make sure you are getting complete penetration. (e.g. Grind the backside of the joint and weld out from that side as well.) Even stick welding it you are looking at the same process if you want a CJP weldment. Not sure the obsession with being able to do it in a single pass.

(Just don't weld it to the frame! )

 

[metal1313]

the first pic appears to have NO welding at all, and no finishing.

that said i would bet the level of testing done on the premade is very high, for liability purposes. and do not weld to the frame, youll have alignment issues, but more importantly will cause stress to the frame

 

[seanmurphy265]

This seems like it is being way over thought. It's mild steel, you have a mig welder of sufficient size, weld it. Mike

I agree! If your concerned about weld strength bevel all of your plates so you can weld on the outside where possible.

 

[petawawarace]

What do you really want to do? Save money or make the part stronger? If its solely a money issue, then just say so, but the part you pictured looks pleanty strong!!

 

[gmwelder86]

Machine ratings are based on shop data. Under perfect circumstances and welders ability. Weld joint design comes into okay with this and two sheets of 3/16 are not the same as 3/8 and with as much weld metal that you would need to put down to do what you want your looking at a lot of distortion just in heat shrinkage.

 

[1SlowFormula]

Ok, so bolting it to the frame it is.

I agree! If your concerned about weld strength bevel all of your plates so you can weld on the outside where possible.

yeah I would bevel the joints to ensure strength.

This seems like it is being way over thought. It's mild steel, you have a mig welder of sufficient size, weld it. Mike

Thanks, but if I just went to welding it before asking my design questions then all you guys who have a lot of experience might be asking me why I did it X way over Y and I wouldn't know any better. The good thing about these forums are having someone who can help bounce ideas off of and do something better than originally planned.

Agreed. Just multiple passes and make sure you are getting complete penetration. (e.g. Grind the backside of the joint and weld out from that side as well.) Even stick welding it you are looking at the same process if you want a CJP weldment. Not sure the obsession with being able to do it in a single pass.

(Just don't weld it to the frame! )

I never meant that I was going to weld it out in one pass, I was answering another post asking if my machine could handle it.

What do you really want to do? Save money or make the part stronger? If its solely a money issue, then just say so, but the part you pictured looks pleanty strong!!

Well saving money is part of it, I'd have to admit that, but in the end I want something similar but slightly different too. Plus I wanted stronger than what other kits appear to have, and without the weld issues I have read about and have seen in pictures. Beyond that I was looking to do it with my current tools and thought forming my own channels out of 3/16, which I have done before, might be an option. From the responses I have gotten though I can see how that wouldn't be the best idea now.



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