Mig Welding Car Panels

[styler]

hey recently got a mars 180 amp mig gas welder with 8 output steps and 10 wire speed settings, has a 15% duty cycle and will be used for the project car. mainly for welding new sections into the cut out sections of rust, ie floorpan, tunnel, rear quarters, engine bay, guards etc... I'm going to practice a fair bit before doing the car and would like to know :

 

1) what gas do people recommend? i think the mix of 95% co2 and 5% argon would be good for welding quality and not too expensive, this might be called mig shield from what i have heard. i do have a 2 gauge regulator (pressure and flow? possibly). seems boc and gas places supply bottles on rent and refills.

 

2) and wire size for old jap ke corolla panels? I'm thinking the smaller the better as i don't want heat distortion, ie 0.6mm. the mig takes 0.6mm to 0.9mm so let me know your thoughts as i have had a few opinions...

 

3) and as for technique i will be learning so feel free to add any constructive basic methods, thinking of short mig welding course at tafe or book. some info on net but seems a lot of trial and error info to suss it out.

 

4) also write up any tips or trick methods, ie stitch welding slowly, cooling panels with water soaked cloths, weld through primers, tack welding sections, clamps, grinding off existing paint/galv etc..

 

:D

Edited March 24, 2007 by styler

[love ke70]

1) not sure on type of gas. but hire a big bottle. the little bottles that you buy and throw away are pigging useless. theyre about 30 dollars and last 7 minutes of welding. big bottle lasts ages, isnt too expensiv to fill up and is only 160 a yr rental...

 

2) 0.8mm seems good. never got on well with the thinner wire..

 

3) TAFE course ftw, saves alot of late nights grinding... (I'm a bigger is better welder, and hence, have lots to grind off, but shes strong!!) lol

 

4)tips and tricks, just take your time and shape the steel, then weld it in. saves alot of bog work.

 

oh and for what its worth, using galv steel is a good idea, as it wont rust again...until you try and weld the shit. its ok once you burn thru the zinc coat :D

[Trendact]

Gas you need is argoshield light (not sure on spelling) Boc can supply this. I use .09 for the trailers but then I am welding for structual strength, Thomo uses the thinner wire I think .06 on the cars in the workshop.

 

You can weld 2 ways, one is to preheat as you go and if you do this on light/ thin steel you will blow holes in it.

 

Stitch welding is the way to go on cars as it allows for movement as the car body moves and do not put cold water on hot welds let it cool on its own. If using Gal grind the gal back to the raw steel in the areas to be welded this way you get a good strong weld with no splatter and no burning of all the nasty stuff used in the gal. Always tac weld into place first then go from there.

 

Penetration is the key, a big blob of weld may look strong and a nice little neat weld may look great but without the right penetration into the two sections of steel the weld is useless.

 

If you are not to sure on anything call your local BOC guy and ask or send me a pm and I will give you a number to contact me on or just call me on the number in my sig at Specialised Trailers....lol

Edited March 24, 2007 by Trendact

[meadan]

we use argoshield at work too for amost all our mig welding. As above, BOC gases can tell you almsot verything you need to know about it, you jsut have to ask them.

Also for the thinner sheet metal on doors and stuff that we use, weve started using 0.6 wire. 0.8 worked fine too, if you know how to set the welder up properly both should work pretty well seeing its not too hard to get penetration through the panels.

To minimise distortion i think youll find lots of smaller but pretty hot welds spread out will work better than long ones. It will look worse before grinding, but will spread out the heat during welding and should still achieve full penetration. As said above, penetration is the key, you don't want to grind away the whole weld and have the parent metal not joined.

My tafe teacher said that if you how to set the welder not much can go wrong. So my advice is to just practice and figure out your technique, and make sure the welder is set correctly. Once you get a feel for it all its not too difficult at all, plus a you can always just get the grinder out and start again..

[Guest Sbox]

Deleted

Edited May 24, 2008 by Sbox

[Guest Sbox]

Deleted

Edited May 25, 2008 by Sbox

[BiGGy]

car panels are very thin, when paints off, they should be 0.6-1.6mm. Make sure you turn the temp way down, try and pulse(spot) weld to learn first. Argoshield is the gas to use, make sure the steel you are welding is clear of rust/grit/paint/oil for maximum peno. When a gas mig is correctly tuned there should be no splatter at all. Play around and take your time to reset your mig at various temps and adjust wire speed accordingly, remember that the distance from nozzle to work peice effects these variables, you should master this before welding anything. Use mild steel mig wire on car panels, anything 1.2mm or less, the welder will be setup for a wire thickness already, just use that. Make sure you buy wear gloves, long pants and long sleeves to stop flash burn. I'm 2nd year boilermaker, hope i helped. pm for any questions.

Edited March 28, 2007 by BiGGy