Hi everyone, I’m trying to MIG weld the wheel arch on my 2003 Mazda MX-5 NB.
Every time I try to weld it, I end up blowing holes through the original sheet metal. Even if I make very short tacks (around 1 second or less) and let the metal cool down between them, it still blows through.
I’m using a STAHLWERK MIG/MAG 160 M. I actually bought this welder specifically for this job because it can run at relatively low amperage.
So far I’ve tried:
0.6 mm solid wire with Argon/CO2 shielding gas
0.8 mm solid wire with Argon/CO2 shielding gas
0.8 mm flux-core wire
With all three I’ve tried different settings, from around 20 A all the way up to 100 A, but I keep getting the same problem.
The original sheet metal on the car is around 1 mm thick. The car does have quite a lot of rust, but I’ve cut away the worst rusty sections until I reached what appears to be solid metal. Despite that, I still can’t seem to weld new metal to it without blowing holes through the original panel.
The replacement metal I’m using is also 1 mm steel.
I have cleaned the front side of the original panel back to bare metal, but I haven’t cleaned the back side yet.
I’ve also tried attaching the ground clamp both directly to the new piece of metal and to clean bare metal on the car body, but the problem is the same.
Does anyone have any advice or see something obvious that I might be doing wrong?
I’ve tried a lot of different things at this point, but I just can’t get a clean butt weld between the original bodywork and the new sheet metal.
Thanks!