[d.b. cooper]

What's the best welding process to use if tacking on brackets to bring to a shop to have them do the final welding? (Someone who knows what the hell they are doing......)


Specifically, it's ladder bar brackets onto a rear axle housing.

Stick, mig or tig? Or does it not matter? i'm thinking most shops will either tig or mig even though tig is probably not crucially necessary in this case?

 

[39 master]

Tack the brackets on the ends so they will not pull out of square. MIG is just fine for the brackets. Make sure they don't put to much heat in at once. Weld half a bracket on one side, then half on the other end of the rear end. Let it cool a bit and repeat. Because you are not welding all the way around the tube heat buildup on one side can pull the tube. Make spacers the same width as the bar ends and bolt them into the bracket to hold them while welding.

 

[d.b. cooper]

That's good to know.

i guess what i'm trying to ask is, IF the shop welds the brackets with TIG, would it be better to tack with TIG?

If the shop welds the brackets with MIG, would it be better to tack with MIG.

Or does it not matter that much?

 

[2old2fast]

Really doesn't matter .

 

[chasracer]

Doesn't matter - just don't use stick. Make sure you have them right because where you put them is where they are going to be.

 

[cerial]

A good shop will grind your welds down and prep the surface. Your showing position once they know that they can prep and apply pretty welds.

That being said practice on some scrap steel/tubing and watch videos and you should be able to make nice welds. This will avoid draging the housing to a shop and waiting several days if not weeks to get it back.

 

[2old2fast]

Doesn't matter - just don't use stick. Make sure you have them right because where you put them is where they are going to be.

What's wrong with stick ?

 

[MGK]

Nothing, is wrong with stick, if you are going to weld it stick, just don't tack it with a stick and then expect a mig or tig to work nicely. Then there is the correct rod, a 7018 would prevent to rapid of heat/cool brittleness. Would be like er70 wire for mig.
Mig is faster and usually easier to get pretty appearance. Tig is probably stronger, but more costly.

I have done a lot of heavy material (carbon steel) welding, multi-pass, build up. I always preferred stick for that.Some days, I would burn 50 lbs of rod. MIG, to get good penetration, you get a lot of splatter, works good up to 1/4".

 

[2old2fast]

250 amp mig welders will easily weld up to 1/2" plate , & those are pretty common in small shops today .er70 or 7014-7018 refers to 70k psi tensile strength , just like 6010 or 6013 means 60000 psi tensile strength . Before small shops had wire feed welders , welding was done through & over factory wire feed welds ( mig) with oxy- acetylene & stick , I can think of no reason why one process can not weld through another process , mig , tig or stick , provided each was done correctly & prepped for the next process correctly . Otherwise , repair work would be nearly impossible .

 

[Camaro496]

What's wrong with stick ?

If you plan to race the car at any time, stick welding is not allowed for rollbars/cages.
It may pass insepction if the tech doesn't check the welds, but if he did, you may not get to run the car.
Not sure why, because my friend was a code welder and welded the towers at Three Mile Island, so if those welds were acceptable for that, I can't see why they wouldn't be for a rollbar/cage, but they still claim it's a safety issue.

 

[2old2fast]

After seeing this rollbar rule , I can only assume that the welding industry lobbied/ pushed this " squirt gun" rule , my only reaction is ," what a crock" !

 

[MGK]

Correctly prepared work is the key to any type of welding. Clean, oil free, paint free. Carbon scale buffed off. Edges chamfered on thick pieces. You have to remember that carbon steel work hardens. So if you make a weld, the area directly adjacent to the bead can be weakened from the rapid heating and cooling as the piece absorbs the heat. I like to preheat the surrounding areas to around 375* to slow the heat wicking from the weld, this also can aid in burning off any contamination from oil or grease that may have gotten into the metal.

 

[cerial]

Mig and stick are perfectly fine for mild steel.
With chromoly steel you want tig as it gives a cleaner weld with less "cracks" in that material.

But the more important then the welder type is the fit. Take a flashlight and shine it against the surface. If you can see light from any gaps then you need to fix that.
So you tack that then weld up and down the bracket using a 5, 10, or 15 rule for a inch or a half at a time distributing heat. Once this is welded you need to think about gussets.

Gussets add triangulation which adds strength. A 90 degree welded bracket can twist. If you add a 45 or even less of a angle gusset then you eliminate that twist. You need to factor in where your bolts and such will be so your not making a headache for yourself later. But generally you can add a gusset easily enough.

To further add strength to gussets(and lessen weight) you can dimple the gusset material then cut the material down. Once again fit is important.

If you have the tig use it. If you have a mig it will work just fine with mild steel.