Electronics > Mechanical & Automation Engineering

Measuring welding current of stick welder



Recently I have purchased a cheap Chinese inverter stick welder and have become somewhat proficient welding thin gauge materials, 16Ga or 1.5mm. I still have blow holes and in the search for improvement, tried to measure the weld current. In doing such measurements, I've discovered that the set current isn't the weld current.

 I was under the assumption that stick welding was a constant current process. Examples of this discrepancy in setpoint  vs measured: 70A vs 59A, 80A vs 62A, 90A vs 67A. Meanwhile, the short circuit current is almost bang on the setpoint current. This was tested with a 1/8in thick x 1.5in wide flat stock that was 30cm long, and cleaned up with grinder. The test electrode was the E6013.

And thus I am questioning if the equipment is junk, or is this standard behavior? I do notice the difference at weld time between selected amperage and how much time before I blow a hole. That will determine how fast I have to go. It's just that some days it feels like that same amperage that I used the day before delivers a different outcome.

Details of the welder are a supposedly 250A max, only 220V AC input, 60V open circuit output voltage.I changed the electrode holder and ground clamp to something beefier and less Chinese. The wires were upgrade to AWS 4AWG welding wire with soldered "dinse 25" connectors. All in the search for low impedance.

Disclaimer: self taught, but many years ago I worked in a metal fabricators as a holiday job so I guess you could say that I have been paid to weld (non structural) stuff, and have done a lot of DIY welding with MIG and stick.

I've never measured the welding current but I've found that the cheap chinese arc welders to be pretty good - way more usable that my dad's old oxford oil filled welder. That said, if I was welding 1.5mm thick sheet then I'd immediately reach for the MIG. As you have found out, using MMA (stick) on thin sheet is a recipe for frustration.

Dont get me started on chinese plasma cutters though. They are definitely rather 'delicate'

Thanks for the reply.

Indeed, the welder does a good job and mostly user error. It's just that in most cases, when learning a new skill, I've learned that starting out with a good tool is important, dare i say a requisite, so not to add to the list of doubts. Just like I am doing, but so far I've done well. It's a hobby and thin gauge materials are the only ones available.

I've had a thought about getting a MIG machine, but they are all out of my price range. I've had a look at some Chinese gasless mig, fcaw, machines that go for about 100 USD. It's the ones with the 1, 2, 3, 4 setting switches. Seen reviews and I'll be up the same alley as the stick welder, more modifying.


If relatively thin sheet is your main thing then it's definitely worth saving up for a MIG. I've never tried 'gasless' MIG, but if its anything like conventional MIG then you will never go back (except for the heavier stuff). That said, due to the mechanical aspect, I think MIG is more sensitive to build/design quality than a stick welder - I'd personally be more wary about a using a budget MIG than using a budget arc welder.

If you really get into welding then another indispensable tool is an autodarkening welding mask - IMHO worth every penny!

1.5mm is very thin for a stick welder (MMA) and you will need quite a lot of experience to do that without blowing holes. MMA becomes a lot easier when the steel is approximately 3mm or thicker.

A "good" welder may help, but in general the cheap boxes are "usable". I would not pay too much attention to what the current knob on your welder says. Just look at the weld. When you blow too many holes, use a lower current and/or thinner electrodes. If the weld does not burn in enough, then you need a higher current. You can get a better understanding for these by taking some pieces of scrap and make a few welds with a too high and with a too low current and observe the results.


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