Question for Al Belli regarding Arc and TIG

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paul skinner
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Joined: Fri Oct 03, 2003 9:59 pm

Question for Al Belli regarding Arc and TIG

Post by paul skinner » Sun Apr 03, 2005 3:18 pm

Al, I'm wondering. Since Arc is so close to TIG, couldn't you just modify an existing cheap arc welder, and add a TIG torch and gas feed? Seems like a simple modification. Or better yet, use and exisiting arc welder modified to a plasma arc welder?

Al Belli
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Location: Pennsylvania - USA

re: Question for Al Belli regarding Arc and TIG

Post by Al Belli » Sun Apr 03, 2005 4:23 pm

Hi Paul,

I use an inexpensive arc welder for My welding, however, I have added several essential modifications.
I use a heavy duty switched resistor bank for fine control of current in the 2 to 20 amp range. I added a full wave bridge rectifier for direct current ( better arc stability ). I also added high frequency starting to eliminate the annoyance of electrode sticking that is caused by scratch starting.
The inexpensive arc welder is used to provide a current limited source of voltage ( ~ 70 V @ 40 A ) to feed the bridge and HF unit.
Direct current is essential for low current welding due to the electron emission effects from the electrode to the workpiece. If You reverse the polarity, the electrode gets eaten up very rapidly. Thir reversal happens 60 times a second when AC welding, and is beneficial in stick welding and when TIG welding aluminum.
The ideal electrode for welding thin stainless steel ( 0.024' or 24 ga. ) is ceriated tungsten . I use a 1mm ( 0.040" ) electrode at 20 amps, and find that if I maintain a pass speed of about 1" every 3 seconds, that the welds are excellent. Shielding gas flowrate is about 8 CFH using the recommended 100% argon.
The HF unit is a spark gap which drives a coil that is coupled to the welder output. I used an oil furnace ignition transformer to power the spark gap which is made from two sparkplugs with the gound electrodes removed, and the center electrodes facing each other with about a 0.030" gap. The coupling coils are made from 1/4" copper tubing.
The HF output is surprising for this simple setup.
If You need additional information, please contact Me at:

bbelli@epix.net

Al Belli

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