Martin Rubenstein

Thanks, Matt: I’ve been waiting for this video. You must have learned to weld on pre-inverter welders (DC generators and transformer-rectifiers), which allowed you to alter the shape of the power (volts-amps) characteristic, from constant current (vertical “curve”) to a drooping/flatter curve. Such a characteristic allows the operator to control the heat input more (by changing the arc length slightly) for out-of-position welds. Some top-of-the-range inverters now let you alter the whole characteristic shape, but the average inverter is constant current at all arc lengths. This is where arc force/dig comes in. It’s a very poor attempt to mimic altering the shape of the whole voltage-current characteristic by giving a boost in current (0 to 100% depending on the dig setting AND the maximum, limiting, current output of the machine) but only at one arc voltage. So it merely puts a kink in the vertical, constant current line, rather than gives it a flatter shape. To be cont

Continued from earlier post…..

So on these typical inverters, dig is less about changing the shape of the characteristic and more about a feature to stop the electrode sticking if the arc gets too short. But if you follow Jody’s golden rule of stick welding, it shouldn’t stick anyway: set the current high enough so that you can keep a tight arc without sticking, and then keep a tight arc. So that’s why you could jam the electrode in at high dig without sticking, and also why the results were not like night and day. So, with a high dig setting and welding with a very tight arc, you’re simply welding at a higher, but still constant, current; if you then back off to a normal arc length, you drop back to the current setting you set up at the start.

This is how I understand it; I’m keen to get your feedback, especially with possible difficulties some people might experience with out-of-position welding using an inverter with some rods (6010?).

Feb 14 at 04:30 PM

JD Brewer well, it was good to see the difference it made, not brushing and brushing. So it was a good demonstration of the benefits. Thanks, JD.

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Feb 14 at 02:11 PM

Cool, JD. I’m glad you decided to SiBr the job rather than making 2 new feet on your miling machine, otherwise the video wouldn’t have been so helpful. (And if it breaks in future, you could always make new ones on the miller?) You got some of the closest arc shots I’ve ever seen. It looked as if the SiBr flowed a bit better after you ground/wire-brushed the first set of deposits; did it seem like that to you? Once you’d wetted the cast iron, the build up seemed quite straightforward. And now you’ve got a very useful machine - worth its weight in silicon bronze!

Thanks, JD.

Martin

Feb 13 at 03:17 AM

“Don’t let the fear of failure stop you from trying.” What an excellent thought to end on. I look forwards to recycling that thought in future. Thanks, Sam.

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Feb 09 at 04:41 PM

Great to see real-world jobs: it helps put things into perspective when we hit the same thing, whilst thinking, “I bet none of the WelderSkills instructors would have this problem.” That old braze material was horrible in the extreme. Thanks, Roy. Great tip about using the standard cup to save ruining the FUPA.

Feb 09 at 03:45 PM

Sorry I missed the live session, JD: I only found out it was on the following morning when I woke up. Got caught out thinking the previous night’s live session with Sam was the Wednesday one brought forwards. The upside is I just watched you and Jody at the 2X speed setting, so I can now go and watch another WelderSkills video with the time I saved, especially one on SiBronze: both you and Sam were talking about it, and it’s something I want to get familiar with. See you next time , live.

By the way, that worktable with the flip out stool… was that Fein, the German company? They make beautiful tools.

That’s a nice-looking milling machine; I was expecting to see a 150-year-old clapped-out piece of junk.

Martin

Many thanks. I enjoyed the live session. The personal stories really add the spice to these conversations. I’m going to go and rewatch the video with MIG deposition of SiBronze.

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Feb 04 at 04:29 AM

Sam That’s why WelderSkills is worth every penny/cent: the rest of us can learn and hopefully avoid the same mistakes the experts made as they climbed up their learning curves. Thanks, Sam.

Feb 02 at 12:18 PM

đź‘Ťđź‘Ťđź‘Ť. Thanks, Sam.

Martin

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