When to change MIG tip

In the last shop I did my apprenticeship my boss would make me go months with the same tip. A quick look at the tip and wire will give you an indication. The wire will wear the hole egg shaped. When you can wiggle the end of the wire back an forth in the hole it is time for a change. A worn tip gives you erratic behaviours. Difficult starts are a common symptom. Randy

And, how long does a tip typically last (in terms of lb. of wire through it)?

TIA, Bob

doh......my apologies to the group for the foul language in my sig line in my earlier posted message. it was "left over" from a flame war in another newsgroup and i forgot it was there until i read my own message.

How long a tip lasts depends entirely on how hard it is being used. At school we run 1/16" dual shield wire all the time and it eats a tip in about 6 hours of weld time.

0.023" tips for 110v MIGs can last a LOOOOOOOOOOONG time, since there is less current to errode them inside.

Anytime that you weld long enough for the tip to get hot enough to produce flakes of scale, it should be replaced.

I replace a tip when it starts misbehaving. Wire popping back to the tip, sticking, stalling, erratic feeding.

Thanks for all the advice. I am using a 110v machine with .023 wire & gas, and typically lower settings (sheet metal mostly). So I guess that my tip wear would be low.

The current one looks OK and I'm not having trouble. But now I know what to look for.

Thanks, Bob