cup size

[GaryW]

Andy,
When using 1/16 electrode for steel header tube what cup size do you recommend and what protrusion (if any) from the end of the cup. Is there are rule of thumb for tip protrusion for both steel and aluminum. I have a 180SD.

[matts427]

Gary, I have the same machine, but for your question, all TIG's are the same. As a good rule of thumb, no matter what size tungsten or amp range, use the largest cup possible. Common sense rules apply here: no need for a 10 cup w/ a .040 tungsten. I usually use an 8 w/ my gas lens, smaller if I need to get in a corner or a very tight spot (headers, tube chassis, etc.) Basically the same rule applies to your stick-out: The less stick-out, the less chance of contamination. I usually stick the tungsten out JUST far enough for me to see the weld OK, further for corners, etc. And remember, too much gas flow is a BAD thing!!!! If you have a gas lens, don't go much over 15 cfm, otherwise 20cfm. Hope this answers your question. And for future reference, Andy is good, don't count him out, but try posting on

http://www.hobartwelders.com/mboard/

There's more people there, and usually a more timely response.
Matt

[ASKANDY]

Matt's right on!

A 6, 7, or 8 cup size for that electode depending on joint configuration would be just fine. As Matt said, adjust your gas flow rate to match the cup size. Smaller cup, less flow (12-15 for 6-8). If you have too much flow, it causes turbulence within the cup and can pull contaminants into the weld. The gas lens Matt spoke of is a great unit. It will however be a bit bigger in total diameter but the gas coverage is much better.

A-