Trying sheet metal....please critique

[Myles1970]

Hi folks.... I want to do some car bodywork soon, so thought I'd try on some sheet metal. It's 0.9mm sheet and I'm using 0.6 mig wire on a Clarke 160t with hobyweld 15 (2% oxygen, 15% co2 and 83%argon). Welder is on lowest power setting with wire speed 6-7. Any advice appreciated, i know I've burned through in a few places, especially where the fit-up is poor. Apart from that is there a hand technique I should be using? I'm just doing what seems like squiggles....or small circles...but the result is a very high weld which will take an age to grind down.

 

[grim_d]

No lies...it's not good.

You don't really want to be moving the torch at all, good fit up and strike right on the butt, allow the puddle to fuse then move on to the next one.

You need to play with your wire speed too.

 

[Shedendman]

https://www.mig-welding.co.uk/mig.htm
Then when you've done that do it again,and again
Your bodywork wont be flat on a bench either,so look around about welding out position

 

[pedrobedro]

Are you holding the torch with both hands ? It's not a water pistol, steady it with your free hand turn the power up a bit and the wire speed down and keep experimenting. Try some lap joints till you get a bit better acquainted with the process.

 

[Burdekin]

Turn it up. You want to do short quick tacs and have good penetration, so you want to turn it up and then cool the weld after. Too low a setting just means you get a poor weld that sits really proud so more grinding, no proper penetration so a weaker join/weld and you need to go slower so more heat into the panel.

 

[backpurge]

When you’ve finished that bottle of gas get one with only 5% CO2 instead of 15%, you’ll find it a bit easier

 

[Myles1970]

Right, taking all your advice on board.

Are you holding the torch with both hands ?

..... No, holding the torch in my right hand, bracing it with my left. I know my hands aren't the steadiest, but trying to work around that.

 

[Myles1970]

These two pics are after upping the power and reducing the wire speed slightly. Also, keeping the torch steady and in one spot. The welds are now lower with better penetration. 1st pic is top side, 2nd is of the underside.

Already, I see an improvement, giving me something to work with.

Gas is nearly finished, so I'll go for 95%ar next time & see if/what difference that makes

.....on the downside, the torch seems to be acting up intermittently, no feed/spark from time to time, I'll have to open it up & have a look

Thanks for the advice lads

 

[Shedendman]

can see what your trying to do,but you need to merge those tacks together,ie
https://www.mig-welding.co.uk/thin-metal.htm

 

[Myles1970]

BTW, the first patch was cut out with a 1mm cutting disk, leaving a gap of about 1-1.5 mm on fit-up.... For this thickness material, would I be better butting them right up?

 

[Myles1970]

can see what your trying to do,but you need to merge those tacks together/QUOTE]

Yep, sorry, my impatience... It was actually a join I had done earlier and ground off...there had been very little penetration, so I thought I'd try again after changing the settings.

Actually, I could probably improve the lighting and get some reading glasses

 

[Myles1970]

ok, last one for the night, think I'm slowly getting there... This was a short cut using shears out of Lidl.. power set to 2, wire speed at about 5.5, using a pulse technique

...this is the underside, showing good penetration away from the edge of the material, I may have been too early of burning through, hence the join is still visible there... More practice required methinks

 

[Burdekin]

For mig you want a gap of 1mm to help minimise distortion. Do one tack, move to the toe of the tack and when it stops glowing do another. You should then get a nice looking weld with overlapped tacks. Watch some you tube videos and keep practicing. Practice with your setting, a flat weld which you can get from a higher setting means less grinding and will have good penetration. Use a damp rag or airline to cool the weld and stagger your welds so you don't put too much heat in one area. This is worth buying and reading: https://www.amazon.co.uk/Welding-Ve...ehicle+restorer&qid=1575637739&s=books&sr=1-1

 

[Burdekin]

Push the torch too whenever you can.