TIG sheet metal with cheap HF

[GeneStoner]

After becoming "proficient" at MIG over the years, I'm trying my hand at TIG for the first time to weld some .025" steel sheet metal.

Unfortunately for me, I'm doing it with an unsophisticated, 1st Gen, Harbor Freight 130A TIG (model 91811). Supposedly a lift-start, with 15CFH Argon, no foot pedal.

I verified its operation on some .200" steel plate at 130A and it does work. But when I changed the settings down to ~25A (hard to tell because the power dial is just 1-10, assuming 10 = 130A and 5, being half of 10 = 65A etc.), I couldn't get the arc to initiate on the sheet metal. Just weak, inconsistent sparks.

What am I doing wrong? Any other tips on using this old TIG for sheet metal?

[whateg0]

I graduated from that welder to my current Square Wave TIG 200 a few years ago. I guess maybe they call it lift-start, but I always referred to it as scratch start, like striking a match. Anyway, I would say you would be lucky to get good welds on that. With a pedal (I started to build one for mine before I sold it.), you might be able to mash the pedal on an adjacent piece of scrap and walk the arc over to the thinner stuff at lower amps, but I would be surprised. I never had much luck with it on anything thinner than about 0.040". That said, I still wouldn't call myself an expert welder, so maybe you'll get it.

[MAC702]

... I guess maybe they call it lift-start, but I always referred to it as scratch start, like striking a match. ...

Different things. Scratch start is the older way where the machine was live and ready to weld, and you did the scratch motion so as not to stick the tungsten in the weld immediately. Lift-start, lift-arc, or whatever that brand calls it, has a dead tungsten, so you can touch it to the work. The machine senses this, and when you lift it back off, it starts the current.