I admit, I have a problem. The little aluminum boat is coming along nicely, except for one thing — the welds are always sooty. Sometimes my welds are too ‘hot’, sometimes they’re too ‘cold’, some are in straight lines, stacked nicely without gaps, while others look like I’ve been driving drunk. But one thing always remains, and that is the soot.

My setup is as follows:

Miller Passport Plus

Spoolmate 100 Spoolgun

100% argon (80 cu ft cylinder)

5052 .080 (12 gauge) aluminum sheet, with 5356 .30 wire

I been using stainless steel brushes, brushing in one direction, both lightly, and more vigorously moments before welding, but there is always the same level of sootiness.

I’ve tried using Ultrabright Aluminum Cleaner, spraying it on, waiting for several minutes, and then wiping it off with a clean towel. Washing it off with water, and then wiping dry was also tried, but always the same level of sootiness.

I’ve tried checking for leaks, but I can detect none. Flow has been 20 to 30, and upwards of 70, but no change whatsoever.

I’m no electrician, so I’m running the welder with the 115 V plug, as we have no ready to use 230 V plugs around. Depending on the temperature, voltage between 3 and 5.5, and 75 – 100 units of wire speed are my usual settings. This is as hot as I can go before blowing through the .080 aluminum, and contact tips.

Trying to keep the proper angle in tight corners has been tough — but the sootiness occurs in any case, and of course, I’m pushing the puddle, not pulling it.

Luckily, this little pram isn’t likely to sink because of the problem, however it’s frustrating that nothing seems to make a difference. Why can’t I get rid of this soot?