TIG

By RFERG43 Date 05-14-2003 21:06

I have graduated myself from a little Miller 130 mig welder. Got a great deal on a Miller 300 amp dialarc tig welder last year and am making progress. I don't have all the burn throughs and sags I did when I started.
I still find the foot pedal somewhat cumbersome. I tend to back off on the current way to much after I get a puddle. I know, PATIENCE!
Looking at the schematic for the welder I found the foot pedal is a large wire wound variable resistor controlling the current through a bucking winding on the transformer. I began to wonder if there is a tig handle with a little trigger on it to controll the current just as the trigger on a variable speed drill controls its speed. Never seen anyting in catalogs such as this. As electronics is my profession, I know there are high voltage triacs (used to control AC voltage) that can handle hundreds of amps. They do not change the phase of the AC, only the conduction angle so I don't see why they could not be used and controlled with a little trigger instead of the foot pedal. I am tempted to try it. Anyone have any thoughts on this. Don't see how it could hurt the welder.

By welder_guy2001 (***)

Date 05-16-2003 03:57

You talk about the amps adjustment on your foot pedal being too sensetive...have you tried turning the main amperage dial on the machine down? say if you turn the main amperage to 300 amps. then the amps can be varied from 0-300 amps. this would be considered too sensetive for most welders. but, say if you turn the main amperage dial to 50 amps, now the foot pedal varies the amps from 0-50 amps and gives you a lot more control over the heat. try that out and see how you like it. if what you're welding needs more heat turn up the main amps control until all you have to do is push the pedal all the way down and you have the optimum heat...no guesswork.

and yes, there are add-ons you can get for your TIG torch so you can vary the amps w/ your thumb or fingers. check out www.lincolnelectric.com or www.millerwelds.com. they're fairly popular, so you shouldn't have any problems finding one.

By RFERG43 Date 05-16-2003 19:36

Thanks for the advise. My TIG is an older one, the foot pedal has a whopping big slide variable resistor in it to control the bucking current so there may not be such an accessorie available for it. Will check out the websites you mentioned though.