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I bought a MIG welder because it has versatility and is easy to learn. After practicing a bit on scrap metal, I'm about to do my first welds on the Alfa.

MIG welding sheetmetal using butt joints is not difficult. As mentioned, it does take some experimenting to find the right settings for amperage, wire feed speed and aiming the gun.

It's important to carefully trim the metal that is being welded together for a close fit. Also, the two panels must be thoroughly clamped so that they end up flush when the weld wire gets shoved at them.
 

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Can anyone suggest a good weld wire for MIG for outside sheetmetal that is easier to grind? The stuff I'm using is conventional steel weld wire and it takes forever to grind off. Also, what is a good wheel to use for grinding?

Thanks for any tips.
 

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Bill77 said:
Can anyone suggest a good weld wire for MIG for outside sheetmetal that is easier to grind? The stuff I'm using is conventional steel weld wire and it takes forever to grind off. Also, what is a good wheel to use for grinding?

Thanks for any tips.
Bill,

I actually use a cut off disc for grinding off MIG welds ... this allows the disk to flex a bit and well I just find it easier. Not sure if it is the quickest method though.

Also I have always found Norton grinding disks to be excellent ... but can't get them anymore for some reason (in Sydney).

Pete
 

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Alfajack said:
One thing people forget about TIG when they promote it is that a TIG is essentially a bench welder. Does a superb job, but you need two hands (one to strike an arc, one to feed the wire) and a foot (to control the heat). Renders them VERY impractical for any kind of welding under a car.
I agree, but I also do TIG welds with a finger control (moves the foot control to a dial on the handle) which allows me to get into many very tight spots comfortably.

still for whacking out some quick repairs while the car is on jacks, I could'nt see any reason not to MIG.
 

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PSk said:
Bill,

I actually use a cut off disc for grinding off MIG welds ... this allows the disk to flex a bit and well I just find it easier. Not sure if it is the quickest method though.

Also I have always found Norton grinding disks to be excellent ... but can't get them anymore for some reason (in Sydney).

Pete
Thanks for the info. I'll pick up some more cut-off discs today. Maybe they will have Norton at the local Production Tool Supply store.
 

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I may be a bit jaded on this subject based on my job history, but......

I am the Quality Manager for a division of my company which does a lot of welding in the factory, as well as a GTV6 Owner. The MIG process is probably the correct answer for many of the reasons already mentioned, but keep in mind that welding thin materials without distortion is not a task for a novice. Even experienced welders can have difficulty with such a weld joint.

In short, welding on cosmetic surfaces might best be left to somebody who has plenty of experience with this type of welding.

My GTV6 restoration needed zero body work, and just a small amount of weld repair on two rusted areas, and I really spent the money to get it in nice shape. You may want to find a car with less body repair needs to begin with.
 

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hutchensgd,
I agreed about saying away from the cosmetics until the novice gets some experiece under their belt. I though, have had a different experience with the professional welder.

I took over the management of the weld shop as part of my duties about five years ago. Trained as a machinist, I didn't have a lot of welding experience.

One day the welders were working on some very thin sheet metal, which in our large shop does show up very often. Seeing the work sparked my curiousity. I called the lead man over and after we talked about the work for a bit, I asked this question. What is the thinnest metal the shop can weld?We finished our conversation without him really answering the question.

About a hour later he showed up in my office and stuck out his hand. Here you go, will this do? In his hand was two gum wrappers (Doublemint stick
kind) welded together. I was speechless.

Some how those wrappers got away from me; but, I'll never look at a stick of gum the same way. I also never take the talent of my man for granted (not that I ever did).
George
 

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To All,

Regarding the use of a Mig welder on the outer sheet metal, one would want to use .025" or .020" (smaller is best) wire with the Carbon Dioxide/Argon (75%/25%) mix. This will give best control and least "weld spatter" (those little metal beads stuck around the weld).

.030" Mig wire works best for chassis.

Mig has another advantage in that it is more tolerant of pollution in the weld area such as a (minimal !!) ammount of undercoating, grease/oil, paint and galvanizing.

Torch is indeed best on outer panels but takes a high degree of skill that many are not able to obtain in a timely fashion.

Tig works well but is brittle. Use coat hangers for welding rod because they are made of very soft steel.

Cheers, Paul V
 

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I have to interject here regarding Tig...The statement of Tig welds being brittle is completely false. They would indeed be brittle if you use coat hangers as filler! Coat hanger wire is the crappiest steel there is! The chemical composition is all over the place. I would stay away from anyone who would use coat hangers for welding work on your project! For reference, have a look at any of the Ron Covell videos on metalworking...
 

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I agree about the wire hangers as weld wire. Good welds require good input materials, like known chemistry of wire, and of course skill! I have never even seen TIG done with a "stick", I have always seen wire fed TIG units.
 

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Ouch!

"Tig works well but is brittle. Use coat hangers for welding rod because they are made of very soft steel."

Well that technique was taught to me when I worked at AAR by Phil Remington, a world class fabricator. His explanation was that body steel was (25 years ago) actually a very soft cheap type of steel and its properties most closely resembled the steel in coat hangers, and that if you used a Heliarc to weld body panels with typical ER6 or ER7 rod, that the weld area would be more brittle (due to a higher carbon content) and therefore could crack when reshaping and planishing a repair panel. He also used coat hangers for torch welding exhaust systems (not the headers though) for all the same reasons.

All I know is this technique has worked for me.

Cheers, paul V
 

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I know a lot of old timers that swear by coat hangers.
as for brittle it seems that if you run a torch over it after it is welded to take out the sharp temper at the weld it will be fine. The tig can heat such a small spot the it cools too quick due to all the cold metal around the hot spot. and that tempers it. So a torch after will heat a bigger spot that will let it cool slower and not temper so much.
They say get a gas set up first then move to tig. As the gas is needed anyways to untemper after the weld. and that the tig works like the gas in many ways.
 

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When i attend a Hot Rod show in Louisville there was a demonstration of a cobra welder gun with O2 and Acethylene. It was pretty impressive and wad welding with a very good penetration while not having too much to grind after. Also contrarly to mig and tig, the metal and the weld is bendable so you can still form the part even through the weld. It also cut very good up to 1 inch steel. Anyway if you want look at it , there is few on ebay http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7538058146&rd=1&sspagename=STRK:MEWA:IT&rd=1 or you can search on their website. It weld anything but titanium. It also come with a video od DVD for even beginers.

Any of you had expereince with this weld gun/ I really plan to get one even if i know nothing. At least i can practice without scrapping the car first.
 

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Hey Bill 77,

Try Klingspor Abrasives on the web, they dropship stuff usually next day, and have very good products.
 

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With all this talk about which method to use in attaching new skin on your Alfa, how do you take it off? For example, how would you take out the spare wheel well? What about the rear wheel well/fender?
 

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I haven't looked at how the spare well is in there...is it a tack welded piece? If so, I'd probably just carefully air chisel the point where its tacked...or maybe use a plasma torch. I'm very new at all this, but I found I could get quite a bit done, pretty precisely, with an air chisel...heck, I even used one to cut an inch deep HUGE section of my concrete hearth extension (fireplace) in my house...I need a compressor and air tools at some point, they're too much fun!

Ted
 

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mubezzi said:
With all this talk about which method to use in attaching new skin on your Alfa, how do you take it off? For example, how would you take out the spare wheel well? What about the rear wheel well/fender?
Drill the spot welds out. You can buy special drill bits for this.

Otherwise buy a 6 inch grinder ...
Pete
 

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i would say to resume , a mig and a very good helmet "automatic "that's expensive but make an enormous difference ,because you can realy see what
you are doing ,it is much more difficult to work with a basic or bad one !
mig soldering is easy if you really see what you do , infernal if you don't !
 
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