h22borikua

Can I weld a roll bar with Harbor Freigh Tig welding machine 130 amp.? or is better a Mig welder 130 amp.? Roll bar it's 1/8 thickness.

9bells

Thats lots for roll bars/cages. More important is the duty cycle, and amp draw.
Make sure the duty cycle is good for intended use, and upgrade breakers if needed.(likely not)
Please use TIG, much nicer.

LSEGHATCH

TIG works great for welding up roll bars, if you know what your doing. IT can be better than MIG in most cases due to a lot of people thinking they can just MIG something together, when in reality they are getting NO penetration and goose **** welds.

JT2MA71

TIG will allow you to better control the heat too, so less of the tubing will be affected and made brittle.

Fenrir51

Why do people think MIG doesnt get good penetration? Why not set it right and it should weld right? Its not like youre welding 3/8ths material here.

I think for the average joe at home in a garage will do fine with a mig for a cage.

LSEGHATCH

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Fenrir51 &raquo;</TD></TR><TR><TD CLASS="quote">Why do people think MIG doesnt get good penetration? Why not set it right and it should weld right? Its not like youre welding 3/8ths material here.

I think for the average joe at home in a garage will do fine with a mig for a cage.</TD></TR></TABLE>

From what I've seen at the local track (oval nascar type ****), people don't know what the hell they are doing. I've seen conduit piping used as a roll cage and the welds on half of the cages are pure ****.

MIG is awsome for something that needs to be done fast and easy, but a lot of people don't realize you still have to set the machine up according to what you are welding.

JT2MA71

My cage is mig'ed. Take your time notching and beveling, same attention to detail you'd expect prepping any work piece. MIG isn't 100% point and shoot, lol.

Most of the crappy MIG'ed cages around here are notched, no bevel, and they don't use enough heat for proper penetration...

hence they look and hold like pure anadultered ***.

vsmhatched

i miged my cage together too...but now since i've learned to tig pretty well, i wish i would have tig'd the cage

9bells

Mig sucks because you could have a very nice looking weld that is just laying on top.
Also, how many guys weld Mig uphand when doing cages?
Stop/starts are trouble for newbs, TIG is more of an art form, good hands will get it done.
MIG isn't like that.
Mig is much faster though.

"Most of the crappy MIG'ed cages around here are notched, no bevel, and they don't use enough heat for proper penetration...

hence they look and hold like pure anadultered ***. "

It's the same everywhere...

h22borikua

Thanks everybody for the opinions. But bottom line, this TIG welder 130 amps 35% duty cycle can weld 1/8 mild steel ? Or Better choise is MIG with gas same amps?

9bells

The tig 130 amps is better.
You will be using 75-90 to weld a cage, and as little as 40 to weld to the sheetmetal on the floor.
130 amps will do 1/4" no problem with a few passes.

h22borikua

Do you have one of those Harbor freight welding machines?

turboteener

This thread is full of BS. A TIG is better than a MIG? Get real. They will both get the job done very well. Any of you guys drive across a bridge or overpass on your way to work? How about working ina multistory steel building. All done with a stick or MIG.

I weld all of my cages in with a MIG, it is faster and easier to get into many positions, especially if you run your cages very tight against the body.

If you are concerned with penetration and not sure which machine to use. Test a few pieces with both and cut the peices apart to check the welds. I assure with proper operation you will get the same level of weld quality.

You won't need more than 110 amps to weld a cage.

8mpg

you can penetrate fine with a mig but tig has a much cleaner weld. I have seen people get booted from the track with a mig'd cage cause the tech inspector didnt like the welds on the cage.

The reason military bunkers and bridges are welded with stick and mig is because of the penetration needed. When was the last time you saw someone welding 1" thick steel with a tig? Tig is used for precision welds and in cases where it needs to look good. It also welds stainless better than a mig will. Go ask all the Chinese about their Liquid Natural Gas tankers and see how they weld their HUGE stainless steel LNG tanks. They will mig EVERYTHING but those tanks. LNG is compressed natural gas...they have to compress it into a liquid and keep it cold in these huge tanks...if their welds are messed up, the thing could explode.

turboteener

MOst tanks are welded by machines that spin the tanks. They are welded with a wire fed MIG machine.
Most of the high pressure gas and liquid lines where I used to work was done with a TIG machine. You can get just as much penetration with a TIG as you can a stick or MIG. Many structures are welded with a wire fed submerged arc machine. Keeps the welds consistent.

I can make my MIG welds look as pretty as TIG welds. Pretty doesn't mean it was done right.

It all boils down to the skill of the operator.

9bells

No, Ihave a miller syncrowave 200.

I wasn't suggesting mig was inferior, it's just easier for a relative newb to recognize fusion with a tig rather than a mig. Of course, all processes are suppose to give the same results when using the same spec of filler, 70kpsi smaw, 70kpsi mig,70kpsi tig, or 70kpsi flux-core.
Are you aware that NHRA/IHRA does not allow smaw to be used when welding a cage? That you have to use TIG when welding chrome-moly?
All the processes are suppose to be equal, but these rules stand.

turboteener

NHRA doesn't allow MIG on a car that goes 7s or faster. They also mandate the chassis be built of 4130. They do allow it on cars that aren't that fast.

You can MIG chromoly, but you will have to normalize the weld afterwards with a torch. Fine for small parts, but not a whole chassis. TIG is in reality the best way to weld chromoly, but it is not in my opinion the best material to build a chassis with. When you weld chromoly you anneal the area around the weld thus negating the benefits of the chromoly. If you weld it with a 4130 rod you will have a problem with embrittlement of the weld. You will then have to cook the chassis in an oven to normalize the whole chassis. Most places don't have the capabilities to do this.

In fact Dodge stated many years ago that it was not a good idea to build chassis out of chromoly.

As long as you exercise proper technique MIG is more than capable for all types of race cars. SCCA, NASA, IMSA, FIA, etc all allow for cages to be built of mild steel and MIG welding.

9bells

All true. The reason every single racer uses chrome-moly is to save weight.
It is true about the process and it's effects on the tube, but it has never been proven to weaken the chassis enough to cause death.
The welding industry is well versed in overkill.
SCCA has recently pulled 4130 from their book, but it doesn't make sense with the cages I have seen pass tech.
The reasons for rules are not always good.
NHRA/IHRA do not allow grinding at all, because it may hide the lack of skill on the part of the fabricator. This ruke stands even though you are allowed to grind when
qualifying for pressure pipe, which has much more severe duty than a cage.

I agree with a skilled operator, and proper fit-up and bevelling, the results can be equal.

turboteener

Not according to my 2007 GCR. SCCA still allows alloy steel. I do agree the reason for rules is not always good.

I do not favor grinding of any welds that are critical. I also don't bevel my cage tubing either. There is not a need to bevel .095 wall tubing to get proper penetration. My MM175 can burn right through without any issues. The only thing I bevel with that welder is stuff thicker than 1/4in.

mrkarl

if you have to ask if the TIG will work you are most likely better off with Mig.

Mr.E.G.

goddamn all of you! everytime i think i have m,ade up my mind about which welder to get i hear oposing views from people who both seem to know what they are talking about. i give up

turboteener

It all depends on your budget, uses, etc. TIG takes more skill in my opinion to get proper penetration without dropout. It is also harder for a beginner to get the right amount of heat with no training. With a MIG you can take a couple of test pieces and set the welder to the factory reccommended settings and go to it. Then you can cut them apart to test.

If you have to ask of a TIG can do it or what not, you should not be welding something that your life will depend on.