# Welding suggestions, from "Precautions when Moving..."



## e_canuck (May 8, 2008)

Wirecutter said:


> I agree with just about everything 1clue says, but I'd like to ask how you pull this off:
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> ...


One of my brothers learned MIG on is own. His work looks very good. He is the one who suggested I get a TIG. He also says it much more versatile. I shure wish he were in the same town as me. Damn jobs.

Anyway. Are you suggesting I should get a MIG or a TIG?
And take a course somewhere?

DP


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## JSRacer (Jun 22, 2008)

MIG is much faster than TIG. TIG takes much more practice to make it look nice. Much more hand-eye coordination. But if you can TIG well, IMO, TIG lays down some of the most beautiful welds. 

MIG and TIG both require a very clean welding surface. Nice thing about stick welding, especially 6010 5p++, is that you can just about weld through anything, even grease. You'd have a hell of a time with MIG and especially TIG doing this.

TIG and MIG also require bottles of straight Argon (TIG mosty) or a Argon mix. Stick does not require anything but the rod.

I know that TIGing aluminum requires a high frequency AC welder with at least 150 amps. And they don't give them away, they're pricey. I'm not sure exactly what it takes to weld aluminum with a MIG but my guess would be a high amperage machine with obviously an aluminum spool. And probably straight argon or a argon/helium mix.

If I were you, I'd find a nice stick/TIG machine and stay away from welding aluminum. Unless you have some reason to weld a bunch of it. A stick welder will TIG. All you have to do is reverse your polarity- instead of + for your electrode and - to your work, you use + for your ground (to work) and the - for your electrode.

Hope this helps! I weld for a living so if you have any questions I'd be happy to try to answer them for you.


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## DavidDymaxion (Dec 1, 2008)

TIG is very easy to adjust on the fly, just push down further or let up on the pedal, spend longer on heat vs. cooling/dipping, and/or weld more or less inches/minute... However, this is a real art and tougher to master.

TIG vs. MIG was a hard decision for me. Obviously a case can be made for both, since both are available and fairly common. I decided on TIG for these reasons:

o I read if TIG looks good, it probably is a good weld. MIG can lay down what looks like a good weld, but it is actually just the wire melted on the metal with no penetration. In any case, you should do some test welds, hammer on them, and cut them to inspect.

o Race teams, and one-off critical welds are often down with TIG -- my car hobby will be mostly one-off stuff. For one-off stuff, design/setup is a big chunk of the time, so it is not so critical if the actual welding takes longer. If I were doing a production shop, then I'd do MIG.

o TIG doesn't smoke and splatter as much as MIG.

Safety warning: TIG is much brighter than MIG, be sure to use a TIG helmet. Also be sure every inch of your skin is covered with leather. My sleeve pulled back once, and about 2 minutes of TIG welding gave me a sunburn that hurt for a week.

My local Home Depot rents MIG welders pretty cheap -- rent it the last hour of the day and have all night to play.



Wirecutter said:


> ... MIG is also easier than TIG because it can leave one hand free. I compare it to hot melt glue for metal. With TIG, you have one hand for the torch, one for the filler wire, and a foot for the control pedal. I don't know how you'd adjust the welder on the fly as I sometimes do with MIG. ...


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## Wirecutter (Jul 26, 2007)

e_canuck said:


> One of my brothers learned MIG on is own. His work looks very good. He is the one who suggested I get a TIG. He also says it much more versatile. I shure wish he were in the same town as me. Damn jobs.
> 
> Anyway. Are you suggesting I should get a MIG or a TIG?
> And take a course somewhere?
> ...


 As you can see here, there are positives for both MIG and TIG. I can't speak a lot about TIG - I can only repeat what I've heard and read. I can confirm that it's not too hard to make nice _looking_ MIG welds that are not good welds. I can also confirm that a good TIG machine is more expensive. To me, anyway, MIG is the easiest and most accessible, and it's what I've got a little experience with. 

edit: Oh yeah - I can also confirm that you want to cover everything up with MIG welding too. MIG can also give you a nasty sunburn with a minute or so of exposure. Ever see the show Monster Garage? Ever wonder why Jesse James always seemed to wear long sleeve shirts with the collar and sleeves buttoned all the way up? I've noticed a lot of welders that do that...

It's easier to learn to ride a bike with someone running along side coaching and perhaps holding you up. Going it alone or having it described to you is bound to take a bit longer. For similar reasons, I would definitely recommend either a course or the help of a seasoned pro. It really shortens the learning curve.

-Mark


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## DIYguy (Sep 18, 2008)

So much good information!.... Let me see if I can clarify a few points..

Both GMAW (MIG is a non standard term actually meaning Metal Inert Gas, which is a misnomer as it typically uses a mix of active gas "MAG" is used more in Europe, here it is GMAW - or Gas Metal Arc Welding) and GTAW (Gas Tungsten Arc Welding commonly called "TIG" for Tungsten Inert Gas) give of healthy amounts of UV light, both will burn you skin and more importantly your eyes. The severity of the burn is relative to the intesity of the arc. The arc intensity depends on a number of things...mainly current. Either process can be done with high or low energy, depending what is being joined.

Al and steel alloys are not welded with the same filler metal. 

Aluminum with GTAW requires AC. The main reason for this is that the heavy oxide layer that is formed on Al is lifted and vaporized during the "reverse polarity half cycle" of AC. This gives the visual of a clear molten pool and keeps contamination away from the melt. The reason for high frequency is purely to establish the arc without touching the electrode to the work. Any contact of the tungsten electrode to the Al will contaminate it and it will have to be re-ground to start over. A foot pedal is often used for this process to vary the current remotely. This is most helpful for Al since the thermal conductivity is so high that often a reduction of engery is required as heat builds up in the work pieces. 

While there are some fairly expensive square wave GTAW systems, you can get into this process for, in some cases, less than GMAW since you don't have to buy the feed system. This is particularly true if you just want to weld steels with DC. For this, no high freq. or remote control is needed and the power supply tends to be cheaper.

Follow the recommendations mentioned regarding training...it's worth it. Yes, TIG takes more skill... wrt hand eye coordination. The point about dirty material is a good one, yes SMAW (stick) can weld through a lot without contamination. . although there is slag and clean up to consider.

Just remember that with GTAW, the torch is a heat source only. The filler rod selection allows you to weld a great variety of materials. The other important aspect to this process is that the current density is quite high. This reduces the negative effect of heat on materials that are sensitive to it. . . hence it's application for critical applications like chrome-molly tubing etc. The larger the heat affected zone, the more concern on exotic materials. Travel rates are slow.

Hope that helps a bit.... 
Remember... "welders get deeper penetration" lol


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## e_canuck (May 8, 2008)

My head is full.

Must.....log.....off.....before.....cra..n..ium.....explo...s......


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## DIYguy (Sep 18, 2008)

e_canuck said:


> My head is full.
> 
> Must.....log.....off.....before.....cra..n..ium.....explo...s......


Sorry man....


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## joethemechanic (Feb 26, 2009)

Mig/tig phoooey. I love my old Lincoln SA-200 Pipeliner, If I burn it in good, it stays stuck


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## John (Sep 11, 2007)

If you have to weld on the structure of a modern car it's likely to be made of High Strength Low Alloy steel. The welding method which will do the least damage to the temper of the steel is Mig due to its smaller heat affected zone.


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## DIYguy (Sep 18, 2008)

If you have a welding machine that works well for what you are doing then...keep doin it! 

Regarding HSLA, that may be true for most uni-body vehicles, but the majority of SUV's don't use HSLA for frames. There are some that do though. I was heavily involved in the development of the welding specifications for Mercedes used on the AAV (before it became unibody). This frame is all HSLA, 50 to 80 ksi. One thing to be cautious of when arc welding frames and heavier HSLA structures (automotive) is that excessive penetration can actually be a bad thing. Penetration in excess of 70% of gmt(governing metal thickness...means thinnest sheet) can lead to early failure, particularly when exposed to high cyclic loading. Critical member should have a penetration requirement that aims for 50% and no more than 70%. I have seen cracks in welds made on 6mm HSLA with 100% penetration... in the as welded state. . . no service influence at all. In general, automotive grade HSLA steels are very weldable and do not have a high carbon equivalency... they use micro alloys to improve mechanical properties. 

Regarding heat input, GTAW has a higher current density than GMAW. GMAW is higher than SMAW. Hi current density is a good thing for a welding process as it allows you to concentrate the energy in a smaller area to limit influence. Either way, not many ppl are going to have much success with stick on sheet metal.

Cheers.


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## 1clue (Jul 21, 2008)

Sorry, I missed this thread and just now realized that I was quoted in the first post.

A previous poster mentioned that aluminum doesn't weld well because it won't feed through the tube, and you need a hand spool.

The welder I'm thinking of does not use one wire for both aluminum and steel. It has a typical steel spool inside the welder just like most of the MIGs do, and then it has a second accessory plug that you can attach a hand spool or even a spot welder, or anything else you can dream up.

I can't afford a decent TIG welder, although I think it would be a great toy.

I went with MIG because it's most practical. FWIW, a buzz box is no longer necessary. Any thickness of steel that a regular buzz box can weld is also weldable by a MIG, if you get a nice enough welder. I have a friend who can weld 1/2" plate steel with a single pass.

I started with a professional welder as a friend. He gave me proper advice, I just didn't listen to him. He has repeatedly shown me how to weld. I am slowly getting it. My welds look less and less like chicken droppings, and more and more like welds.


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