Incoming MIG welder query

[History]

Bacon butty with HP sauce and sausage butty with English mustard.

Sorry for the mission creep but Rich is hungry.

Bob.

[JPB]

I don't use MIG these days, other than at work if I'm showing a student how not to do it. Even thin car bodywork can be done effectively with an arc machine, especially with the carbon torch, which sounds more like grilling toasted cheese than frying decaying flesh from the carcass of a close relation.
Oh, and carbon arc is also suitable for making spot welds. OK, so you can plug weld with any type of welding equipment but sometimes, only a factory style weld will cut the mustard, assuming that Rich hasn't eaten it all on his cow sandwiches.

[Murray]

Thanks for all the information.
I think I will give the Clarke 135 a try along with a big gas bottle and automatic mask.
looking forward to teaching myself a new skill,but stand by for some stupid newbie questions.
Thanks again guys I appreciate the input.

Dermot.

[tractorman]

I used to use a stick welder and carbon arc torch, but I would be a little cautious with one on modern cars. The main reason for the MIG was that I was told that oxy welding isn't suitable (MIG weld uses HT filler"rod") - and I got oxy because it is much more versatile than carbon arc (and you don't weld in two places when working in tight spaces - when the electrode holders hit the body!). I'm sure modern inverter welders are more practical than the old SIP one I used (and probably don't cost that much more) but the big advantage of MIG is that you don't put so much heat into the area around the weld as a gas or carbon arc-produced flame. I had some lovely rippled panels with the carbon-arc torch!

If I hadn't already got the oxy set, I would have considered a TIG, though I tend to use oxy more for heating and cutting than welding these days and the MIG is first choice for a quick (if relatively messy) welding job.

[History]

I was taught gas welding and brazing bronze welding as an apprentice. Oxy acetylene is very useful on older cars. I can do neat strong welds that only need a touch with a sodt disc to smooth out. The big problem is distortion its difficult to control. But combined with mig mag welding set .every welding task on old cars can be done. Gas is also handy for forging stuff. Stick welding sheet steel spot weld style is quite a neat way. I hold the end off the electrode with welding gloves and pop pop and its done and lokking good.
Brazing and bronze welding are viewed with suspicion by the MOT guys but both are quite strong and would be ok for cars except the fore mentioned MOT. I like the smooth flow of brazing its like solder. Also it has caliperary action and goes inside the joint which gives much bigger surface area. Lap joints are good but butt joints need parent metal filler rod welding.

A tip ia to cut narrow strips of the same metal that is being welded and use as filler rod. Especially aluminium that is not painted. Aluminium filler rod from suppliers won't be the same colour and it will show. Plus the filler rod may softer or harder than the parent metal leading to problems when tapping up the welds to make them invisible. I made a deeply valanced cycle guard in two halves. And weld the guard down the middle. Because the curve was a bit wavy
I wheeled it down the weld after the weld was smoothed out by sanding. Unfortunately the filler rod used was to hard and it wouldn't straighten the wavy bits. It took ages to get it right. No bondo allowed.

Newer cars have steel that is heat treated this means any welding process that exceeds 500c will change the mechanical properties of the steel.

Bob. Professor of the bleeding obvious.

[Flatlander]

Reading through this thread, there is, imho, some good advice and bad advice.

My own personal opinion...anything less than a 150A welder is pointless. My own preference is around 180A, but on the other hand, I have 3 phase electrics in my workshop, so things are a bit different.

As regards "learning from the web." The only way to learn is practice, and if possible getting advice from an experienced welder.

Aluminium welding. Use TIG...

Finally, being pedantic, cars are usually MAG welded....

[JPB]

....being pedantic, cars are usually MAG welded....

That's not really pedantic, but given that MIG is a sub genre to MAG and that MAG can mean either of two things, so is a coverall which undermines the usefulness of the acronym, MIG is probably the more elegant term as it comes without the ambiguity.

Now that's how pedantry should be done!

[Flatlander]

....being pedantic, cars are usually MAG welded....

That's not really pedantic, but given that MIG is a sub genre to MAG and that MAG can mean either of two things, so is a coverall which undermines the usefulness of the acronym, MIG is probably the more elegant term as it comes without the ambiguity.

Now that's how pedantry should be done!

Or GMAW...

[JPB]

That's me thoroughly out-pedanted then..

[arceye]

Bloody hell, nitpickers

I served my time as a structural steel and thick plate fabricator welder, and then went on to working on railway structures so am really only a rough round the edges type tradesman.

However, I'm going to fly in the face of this and say there are only 4 names you need to know for general welding processes, MIG, TIG, GAS, STICK that's it, Oh, unless you weld rails when you get into Thermit welding, unless you want to call it Thermite welding or Exorthermic Bonding but why complicate things, we all know what processes the first 4 apply to......

they may not always be correct but are descriptive and any bloke covered in rust / grime / and 150 year old lead paint will know what you mean.

Whether its actually an "inert" or "active" gas ain't really going to make much difference to the average bloke in his shed, well, providing he doesn't try hooking up something flammable to the regulator of his Mig Mag GMAW welder

But yeah, practice, practice, practice is the only real way to learn how to lay down weld that actually holds different pieces of metal together.