Miller! The miller welders we use for FRC do daytime duty as votech teaching machines, and nighttime duty as adult teaching machines. I’ve never used a TIG machine better than a Miller Dynasty, but that was ~$15k!
Also, if you’re welding steel up, I’d encourage you to look at 4130 steel for your frame. It’s wonderfully strong, can weld like a dream, and TIG-brazes beautifully with silicon-bronze.
So can I, and many other people. When I was teaching welding a petite young woman struggled really hard welding with an air-cooled Miller setup. No tips/tricks/help was enabling her to weld at a high quality level. On a hunch I moved her to a Lincoln machine with a liquid cooled torch. An objectively worse welder, but she was no longer straining hard to keep the torch steady and became one of my best welders.
It would be an outright shame for an FRC team were to miss out their potentially best welding talent because they tried to scrimp a few bucks by going with air-cooled over water-cooled.
Maybe you should change that because Thoriated tungsten is radioactive.
Are the normal doses of this material dangerous? Probably not. However, when students are involved who may not be aware of the risks, or if you do the right thing and tell their parents ‘your child is working with a radioactive material’ (which any ethical welding instructor should be doing) the optics of the situation are not good. There are plenty of other tungsten electrode alloys that do not have these health risks that provide equivalent or superior performance.
I use lanthanated electrodes because that one formulation will do everything well, especially the super-thin materials I tend to weld these days.
[quote]Lanthanated (Color Code: Gold)
Lanthanated tungsten electrodes (AWS classification EWLa-1.5) contain a minimum of 97.80 percent tungsten and 1.30 percent to 1.70 percent lanthanum, or lanthana, and are known as 1.5 percent lanthanated. These electrodes have excellent arc starting, a low
burnoff rate, good arc stability, and excellent reignition characteristics—many of the same advantages as ceriated electrodes. Lanthanated electrodes also share the conductivity characteristics of 2 percent thoriated tungsten. In some cases, 1.5 percent lanthanated can replace 2 percent thoriated without having to make significant welding program changes.
Lanthanated tungsten electrodes are ideal if you want to optimize your welding capabilities. They work well on AC or DC electrode negative with a pointed end, or they can be balled for use with AC sine wave power sources. Lanthanated tungsten maintains a sharpened point well, which is an advantage for welding steel and stainless steel on DC or AC from square wave power sources.
Unlike thoriated tungsten, these electrodes are suitable for AC welding and, like ceriated electrodes, allow the arc to be started and maintained at lower voltages. Compared with pure tungsten, the addition of 1.5 percent lanthana increases the maximum current-carrying capacity by approximately 50 percent for a given electrode size.[/quote]
I learned how to weld on aluminum. I then started teaching aluminum first. I am generally able to have a student laying a decent bead within 2 hours, some more some less. While it shouldn’t be taken lightly, start-up training time can be somewhat short. After ~12 hours of shop time (really 3-4 hours of torch time each) my students were able to make a sheetmetal aluminum weld that passed a tensile test.
I know that I picked on your post pretty hard. Most of the information you supplied is good, especially the three Cs of welding: clean, clean, clean. The three points I addressed are admittedly pet peeves of mine that I feel compelled to speak up about.