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takeitsleazy 08-12-2013 09:38 PM

Arc sufficient for cage?
 
Im looking at different cages, some of them being weld in, but all I have access to (or proven competency at) is stick welding. Are mig welds that much stronger? Or could arc work?

Kettles 08-13-2013 05:26 AM

I would dread having to stick weld a cage due to it being all out of position, but if you are competent with the process there is nothing wrong with it.

Holder350 08-13-2013 06:06 AM

Arc is more structurally sound than mig anyhow.

Sent from my phone

takeitsleazy 08-13-2013 11:22 AM

Just what I wanted to hear, thanks for the quick responses!

jason280 08-13-2013 06:15 PM

Quote:

Originally Posted by Holder350 (Post 15788371)
Arc is more structurally sound than mig anyhow.

Sent from my phone

Clarification, please...

Holder350 08-13-2013 07:04 PM

Mig welding requires a very clean weld joint and environment to produce good welds.

Arc welding does not require the pristine clean joint that mig does and it has less chance of inclusions in the weld.

Tig is the first choice followed by arc then lastly by mig in my opinion.

Never seen mig rated as an acceptable method of welding structural joints. But I don't hold a cert in structural welding or anything.

Sent from my phone

jason280 08-13-2013 07:57 PM

Quote:

Arc welding does not require the pristine clean joint that mig does and it has less chance of inclusions in the weld.

Tig is the first choice followed by arc then lastly by mig in my opinion.
Not sure I follow your logic. One minute you praise stick welding as it "does not require the pristine clean joint that mig does", yet state in the next sentence that TIG would be your first choice. TIG requires just as clean a surface, usually even more so than MIG, so I am not sure what you are suggesting. Plus, it is considerably a slower process, and certainly would not be my first choice for a cage.

Just a little food for thought, but the majority of NASCAR cages (if not all) are MIG welded....not stick or TIG. ;)

Quote:

Never seen mig rated as an acceptable method of welding structural joints. But I don't hold a cert in structural welding or anything.
Its my understanding, and I could be completely wrong here, that the reason you see stick primarily in structural welding is twofold. One, its a lot easier to run longer leads, and two, the flux coating shields better in an outside environment than MIG shielding gas. It would be difficult to try and feed MIG wire through 50-100' of liner, whereas running 100' of stick leads is a piece of cake. Also, have you ever tried MIG welding outside? It can be a nightmare with even the softest of breezes, which isn't much of an issue with the flux on a stick electrode.

As far as the topic at hand is concerned, there is no way you can get a structurally better weld with stick over MIG on a roll cage. 7018 is still 70k rod, and ER70s is rated the same. Only issue one would have is if the amperage wasn't comparable....say a 140a MIG vs an AC/DC 200+ amp stick.

Holder350 08-13-2013 08:47 PM

Mig welding tubing will require a gapped joint for full penetration.

Heliarc would be my first choice because of the ease of heat control you have with it.

Arc would be just as strong as heliarc but much quicker and easier.

I've worked with several welders in industry and have never seen a mig used on anything that had to be certified.

Sent from my phone

jason280 08-13-2013 10:04 PM

Quote:

I've worked with several welders in industry and have never seen a mig used on anything that had to be certified.
Ok, I'll bite...considering you've never seen a MIG used on anything requiring certification, how many roll cages have you seen being built professionally with stick machines? Take it one step further, how many Wrangler roll bars do you think were factory stick welded over the years? Not that it matters, but in the grand scheme of this discussion, what do certifications even have to do with a guy building a roll cage in his garage?

Regardless, this thread has gotten too far off topic. If the OP feels competent enough in his abilities to weld thin wall tubing with a stick machine, then there is no reason he shouldn't go forward. 3/32 7018 @ 90-95 amps has worked well for me on 1/8" steel, just be careful not to blow through. Thin steel can be a different animal for stick welding, but it can be done in capable hands. Its really better suited for MIG welding, and until I hear NASCAR has switched to Lincoln buzz boxes for cage building, I'll stick with .023-.035" solid wire...

Ironworker709 08-13-2013 10:07 PM

Quote:

Originally Posted by Holder350 (Post 15791661)
Mig welding tubing will require a gapped joint for full penetration.

Heliarc would be my first choice because of the ease of heat control you have with it.

Arc would be just as strong as heliarc but much quicker and easier.

I've worked with several welders in industry and have never seen a mig used on anything that had to be certified.

Sent from my phone

I DO weld in the industry and GMAW is a VERY common process in the structural fabrication shops and inside buildings being built that is sheilded from wind,,,it has been for a few decades and more....

I've ran miles and miles of hardwire in fab shops for structural and pipe and vessels..all Xray and UT.......

Our apprentice weldors now days have to learn and certify in GMAW..FCAW and SMAW..TIG is an option for us..we don't use it as often as boilermakers and pipefitters...

FCAW and Dual Shield is dominating the new infrastructure in USA now...NR233 is the required wire for all structural buildings and bridges now on any load bearing moment welds and connections on the main frames.......no more NR211 at all,,and NR232 is being phased out with NR233.....it's nicknamed the "earthquake wire".....

And as far as MIG needing gaps for a full pen...ALL processes need it..no difference...

takeitsleazy 08-14-2013 05:05 PM

learning from all of this, great discussion! i need to browse this section of the forum more often

andrewmacc 08-15-2013 12:49 AM

Quote:

Originally Posted by Holder350 (Post 15791661)
Mig welding tubing will require a gapped joint for full penetration.

Heliarc would be my first choice because of the ease of heat control you have with it.

Arc would be just as strong as heliarc but much quicker and easier.

I've worked with several welders in industry and have never seen a mig used on anything that had to be certified.

Sent from my phone


:rolleyes:

Other than the hassle of wind and needing to run 50 feet of wire through a whip, there's no logic to your reasoning. SMAW is used structurally where it is difficult to have a wirefeeder, for convenience and ease of dealing with the elements, period, not because it is weaker.

Unless you're up 100 feet on steel beams or hanging off a rafter in a mine, FCAW is used all the time in structural. In fact, they're currently building an overpass on the highway near my house and I watched them all run FCAW while joining the structural "posts" that are hammered into the ground by gigantic machines (my terminology is lacking here).

And curious you'd choose TIG first. It's hardly cooperative with any amount of contamination.


edit:
to stay on topic, you can definitely weld a cage with SMAW. It won't be fun, and it likely won't be as aesthetically pleasing (big whoop). SMAW isn't as tolerant of gaps as GMAW is, but just means you need to get your fit-up on spec, which is a no brainer for a cage anyway.

Strings72 08-15-2013 08:45 AM

It's not the wand, it's the magician. SMAW (arc) is by all means acceptable for cage welds if you are a capable welder. If you couldn't go and pass a 6G weld test or at least be confident in your vertical and overhead welds then I would reconsider potentially trusting your welds with your life.

schitzangiggles 08-15-2013 12:21 PM

I was told that weldments that have been done with a SMAW and a heavy flux are stronger as the weld gets too cool slower because of the slag retaining the heat.
But I could be wrong as it has been a while since I stayed at a Holiday Inn Express...

Shadownwpa 08-15-2013 01:31 PM

All these experts... it's incredible :drool:

A brief glossary:

Arc welding - Welding with the use of an electrical arc producing the heat required to melt two parent metals together with or without filler metal - includes gas metal arc welding (mig, gmaw), shielded metal arc welding (stick, smaw), and gas tungsten arc welding (tig, gtaw).... and many more.

Heliarc - Tig welding using high frequency alternating current (achf)

ALL WELDING requires clean metal to produce a sound weld, though some will show it more immediately and more visibly. Don't believe me go stick weld a groove over some grease, sand or paint and put it in a bender.

Can you weld a roll cage with stick? yea. If I had to I'd probably tack it in position, brace it, pull it out, and roll it so all the welds could be done flat for best visual appearance and penetration. I'd prefer mig though.


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