Setting up 165T MIG for bodywork.

[DevilDriver]

I'm mid way through a restoration on my old Polo and the battery tray is a mess of poorly executed welding and rot..It's getting cut out and new metal welded in.

Im using a 165Turbo, C02 gas and a 0.6mm tip and mild steel wire. Would i be better stepping up to .8 wire? I am told that you can get the same level of build on the weld without having the wire speed (and therefore amps) so high. I've tried setting the welder with limited success. 1 MAX and about 4 on the wirespeed seems ok, but on metal this thin its easily burnt through. The battery tray won't be so visible but i'd like to replace on of the rear arches so that would be more visible.

Any advice is much appreciated. Thanks!

 

[shenion]

You want to use 0.6mm on thin stuff.

Wire speed will be higher than 0.8 but the current will be lower.

 

[DevilDriver]

I thought that the current rises as the wire speed is turned up, so to get the same fill to the welds using .6, the wire speed will be higher than .8 or am I missing something? Cheers!

 

[shenion]

Yes current is proportional to wire speed but it is also proportional to the wire cross area.

0.6mm wilre is just over half the size of 0.8mm (0.563). SO the current is less so it needs a much higher wire speed to get the same current.

Generally, 0.6 will let you run a lower current even with a higher wire speed.

 

[DevilDriver]

Ah brilliant, i get what you mean now. I had varied results with welding up a few holes in the bootlid but i believe i had over prepped the metal before welding with a 40g flap disc leaving it too thin to complete a strong butt joint.