Size of the cup?

Attachment 1468So anybody got some easy rules for following the size of the cup? Does it matter if I have an oversized cup on? I bought this half inch cup and so far I like it. I had intended to use it for messing around with titanium. I think its about half inch. Whatever a number 12 is? So I was more curious on wether or not does it matter if you over shoot on the size of your cup? We are talking tig welders here, lol. I attached the cup to show you. The one next to it is the largest that came with the 250. Makes it look tiny.

Frank,

No harm in going to a larger cup except that it restricts your view a bit and would be harder to get into tight spots. You would probably need to increase the gas flow. I use an oversized one for stainless work.

Your number 12 cup would be 12/16 of an inch. In other words that cup has a 3/4 inch hole in it.

Check out the miller site for rules of thumb but what I’ve seen is this:

Cup size (in 16ths): 3 to 4 times the electrode diameter (so for 1/16 tungsten use a #4, 3/32 tungsten use a #5 or #6 cup, and so on).

Tungsten sickout: No more than the cup diameter.

Gas flow: Same litres/min as cup size.

Post flow: 1 second per 10amps of current.

Chris
Brisbane Australia.

Hi Frank,

Here is a video using a large size cup for titanium even though the title indicates stainless: http://www.weldingtipsandtricks.com/...stainless.html

Thurmond