Picked up a mig welder

[xmetallicaxguitaristx]

Me and my friend were doing some exhaust work and decided we wanted to split the costs of a used welder.

Well... the real reason was I lowered my car recently, and my cutouts welds (ghetto brazed with oxy/acet) broke after slamming into something when bottomed out. So.. it was scraping on the floor. Literally dragging.

At the same time, my friend was in the process of gutting his cats (GTO), and he wanted to weld the pipes back up.


So we looked through craigslist, and after like 6 calls, we found a mig welder for $100. Basically it's an older (like 8 years old) century welder that the guy only used for exhaust on his car (mustang lol). It still works perfect, the guy never used it much after he got rid of his mustang and it was taking up space.

It is just a basic welder but it works great and I have already gotten it's moneys worth ($50 on my end). I am sure the thing cost >$500 though new.


Now my only question to you guys..

I had some flux cored wired that came with it. I think it was .035 steel, and then there was some copper wire too. I already used all of the steel wire. When I was welding, there was like a white powder residue left over after welding. I am assuming that has something to do with the flux right? It almost looked like oxidation, which to my knowledge is WHY you are supposed to use an inert shielding gas (in this case the flux cored wire) to prevent that.

Was this wire bad?

I heard it's a lot cleaner weld if you use argon or something for a shielding gas.


If the wire WAS bad, where can I pick some up and how expensive is it? I can order online if you guys know any cheap places.

As far as the argon or shielding gas, where can I get a bottle of that and how long will it last? Would it even be needed for exhaust work?

[zz_camaro_zz]

Re: Picked up a mig welder

The white residue is normal with flux core wire if you aren't using any shielding gas with it. i would recommend that you use the normal welding wire (the cooper looking one) with shielding gas for your exhaust welds. using flux core wire isn't as good as some people think it is.
You can get a bottle of gas from just about any welding supply company. i have a 20 pound bottle for my home welder and i bought it for 100 bucks and then had it filled for 35 bucks. but every company is different so prices may vary.
as for how long it would last, a long time as long as you remember to shut off the bottle when your done using it.

[poncho1961]

Re: Picked up a mig welder

Unless it came with the welder, you'll need a regulator flow meter for the bottle also. An 80/20 mix of argon co2 will work great with the copper colored wire, its not really copper. Its available from welding supply houses in 4 or 5 different sized bottles and prices vary according to size.

[Leonard 3.8L]

Re: Picked up a mig welder

I don't think white-powder residue is something to worry about.
< took mig welding in high-school; sounds like it works nonetheless.

[ssms5411]

Re: Picked up a mig welder

I have a lincoln pro mig 140 and I just use .035 flux, one of these days I'll get the gas for it. The flux works good on exhaust pipes once you get use to it but gas is the way to go, you get better looking welds.

[4thgenowner]

Re: Picked up a mig welder

I suggest gas. I've gotten so much better results with it.

heres a pick from my exhaust install. not my best welds but I used gas.

[xmetallicaxguitaristx]

Re: Picked up a mig welder

Yeah with the flux, it was a decent weld, it just looked like **** with all the white around it.

That and I have only ever touched a mig welder one time in my auto tech class like 3 years ago.

As far as technique, do you just drag it straight down? I have heard people talking about using a stitching motion. What were they talking about?

Your weld looks like mine. I am guessing you just went in a straight line right?

I am guessing you are supposed to do this type of thing when welding exhaust type stuff together right?

[IDoVoodoo]

Re: Picked up a mig welder

i just make little circles, i like it better than the zig zag method

[xmetallicaxguitaristx]

Re: Picked up a mig welder

Ok so I have been reading more, and apparently it is normal to look like this with gasless wire:



And they say if you want it to look like a normal clean weld just clean it up with a wire brush and then it will look like this:




And also apparently since the slag is non conductive, after you say, tack weld, you would have to clean the slag off before you weld over it cause the slag would prevent a good connection since it is non-conductive.

Also I guess since the slag is non-conductive you are then supposed to use just a zig-zag movement like this, so that you aren't going back over the non-conductive part to make a messy weld.



Man I can see how even professionals can keep learning.

[4thgenowner]

Re: Picked up a mig welder

I use a circle pattern because exhaust tubing is thin and to me it gets better penetration.

[xmetallicaxguitaristx]

Re: Picked up a mig welder

With the gasless you can't go back over the weld though because of the flux core.

[ssms5411]

Re: Picked up a mig welder

With the gasless you can't go back over the weld though because of the flux core.

You can go back over the weld , just need to turn the heat up like if you had it on B turn it down to C(which is hotter on mine) and turn the wire speed down, it will heat up the existing weld. I have had to do it before. I also just spot weld a couple of places, then go back and fill in the rest. I hope to get gas for it one of these days it just looks so much better, also remember to spray it with some non-rust paint after cleaning up the weld with wire brush or if need be grinder.

[ssms5411]

Re: Picked up a mig welder

I suggest gas. I've gotten so much better results with it.

heres a pick from my exhaust install. not my best welds but I used gas.

Thats a great weld using gas, I wish mine all looked like that. Nice job.