Katahdin
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Finally took the plunge and got a mig welder two weeks ago, after playing around a little bit this was my first attempt at patching a rust hole. The project was the driver's side fender.
Of course everything got a bit more complicated once you got into cutting the metal. I originally thought I could get away with patching it in two places, but a couple spots were too pitted/thin to weld and then found I some rust sandwiched between two sheet metal panels. In the end I welded in 5 patches.
A couple times it burned through, of course, so I used a piece of aluminum behind the area I was welding to prevent that. The steel does not stick to the aluminum and helps dissipate the heat.
On the pieces of metal that were back-to-back, I sprayed on weld-through primer. I also employed magnets to hold the metal in place where I needed. Welding wire was .30, which came with the welder, I understand .25 might be a better size for sheet metal and less prone to burning through because it carries less current. Gas was C25. Welder was a Miller 211 using 110V. I played around a bit with the voltage and wire feed speed as I work on the fender, being a newbie I just couldn't leave that alone. Other tools was a grinder and angle grinder with cutting disks. Thick cutting disks on the angle grinder were also good at grinding down the welds.
Worst mistake was cutting the large patch a little too narrow, it was a PIA to fill in the gap, I won't make that mistake again.
It took a good part of a day to do this, but I enjoyed it and with any luck my skill will get better.
Of course everything got a bit more complicated once you got into cutting the metal. I originally thought I could get away with patching it in two places, but a couple spots were too pitted/thin to weld and then found I some rust sandwiched between two sheet metal panels. In the end I welded in 5 patches.
A couple times it burned through, of course, so I used a piece of aluminum behind the area I was welding to prevent that. The steel does not stick to the aluminum and helps dissipate the heat.
On the pieces of metal that were back-to-back, I sprayed on weld-through primer. I also employed magnets to hold the metal in place where I needed. Welding wire was .30, which came with the welder, I understand .25 might be a better size for sheet metal and less prone to burning through because it carries less current. Gas was C25. Welder was a Miller 211 using 110V. I played around a bit with the voltage and wire feed speed as I work on the fender, being a newbie I just couldn't leave that alone. Other tools was a grinder and angle grinder with cutting disks. Thick cutting disks on the angle grinder were also good at grinding down the welds.
Worst mistake was cutting the large patch a little too narrow, it was a PIA to fill in the gap, I won't make that mistake again.
It took a good part of a day to do this, but I enjoyed it and with any luck my skill will get better.
