roll cage

[muthstryker]

i was just wondering if some of you know what would be the best method for welding a roll cage together. my dad knows how to weld so it shudnt be a problem but what kind should be done?

[Blown353]

Tig.

[Matt@RFR]

Tig.

Why? And bring the tech.

[MoeBawlz]

I had mine welded in with my mig welder by a professional welder. He said it would have no problems at all because I asked the same question and this is the guy who has been doing structural welding for 20+ years so I'd trust his expertise.

[Damn True]

My source informs me that Tig is best used on a Cro-Mo cage. Cro-Mo will be marginally lighter. The material is much more expensive though, and the process requires 2-3x the man hours as a Mig welded mild cage. Which will further add to the expense.

[quadfather]

tig. because it's sooooooo pretty.

[Speed Raycer]

There's "knowing" how to weld, then there's KNOWING how to weld. I've seen cages that were welded together by people who "know" how to weld with zero penetration. I've also seen cages welded together with a stick welder... apparently with their eyes closed ;)

Anyway, MIG is completely acceptable for use on a 1018/1020 Mild Steel cage. 1018/1020 can also be TIG welded.

4130 is TIG only and should be avoided if it's your first cage. 4130 isn't lighter than Mild Steel.. you're just allowed to use thinner wall sizes, which is where the weight savings come from. With steel prices as crazy as they are right now, 4130 isn't all that much more expensive, but the install time is 3-4 times as long (as mentioned above).

TIG will get you a prettier weld with almost 100% guaranteed penetration, better fitment of the tube to tube joints.

Also, just like Paint and bodywork... the quality of the weld starts at the prep of the joint. No more than 1/16" gaps, shiny metal at least 1" from the cope and wiped down with acetone before you even make a tack weld.

Just my $.02

[Blown353]

Why? And bring the tech.

No real reason other than appearance.

That being said a good welder can put down an excellent looking bead (and more important a structurally sound one) with a MIG. Given the proper tools, the guy running the equipment is always the biggest factor!

Should have given more than a one word answer I suppose, didn't elaborate on mild vs. Chro-mo, are the soft interior bits still installed so is there concern over weld spatter, etc. Meant to give some more info but I was replying at work and had to dive away from my desk for a while so I hit the submit button and left.

[Matt@RFR]

MIG or TIG?

Given the proper tools, the guy running the equipment is always the biggest factor!

There's the correct answer given such a general question.

[cagedruss]

Actually 4130 can be wired fed (mig) with proper wire and gas. Sanctioning bodies do not allow mig-ing 4130 because it is easier to screw up. If I am doing a cage for a Pro-touring street car, I tig weld it. The quality of the weld and looks are better and Pro-Touring is about quality and looks. If it is a race car and is Mild Steel, MIg weld is the only way.

I can buy 4130 for the same price as DOM now. Stay away from the ERW, will save a few dollars but it is crap.

Tig welding should only be about twice as long if you are doing a straight forward 6-8 points. Takes longer if you are doing multiple door bars.

Tig weld it if you can. If the welder does not have as much experience as Speedy and I, it is easy to get huge welds around the tube joints and will detract from the over all appearance.

First pic of Mig on 1020, Second of Tig 4130 and third is of a Welder's cars (home Job). Failed tech and I have to remove the whole cage.

[6'9"Witha69]

Holt crap, that last pic looks like the cage puked! No wonder it failed tech.

[Damn True]

SCCA does allow mig welded cages.

[Mean 69]

Failed tech and I have to remove the whole cage.

I hope the owner of the car isn't too upset about having to have the entire cage re-done, because if that weld (or whatever you call it) is ANY indication of the lack of quality of the rest of it, it's likely the thing wouldn't be able to do its job if needed in a crash to begin with. A false sense of security about "having a cage" in the car, when the cage won't hold up, is probably worse than not having anything and being a bit more cautious.

I have seen way, way more bad attempts at doing a cage than I have seen good ones. Race cars included, but mostly on street cars.

Mark