All welding supply houses have .023 and .025 as well as others.

DADS50 has a great point, get the easy grind. Not only does grinding go faster but you will generate less heat and again less distortion to your panels.

My Lincoln welder accepts both.

Check your manual, you will need to change the tip as well,

Good luck.
Mikey


1951 Chevy 3600 rust bucket with GarWood dump bed conversion
http://www.flickr.com/photos/mikeybs51chevy