My Lincoln SP135 had a gun with an exposed, unlocked trigger. Too often
I'd set it down, bumping the trigger and running out wire that had to be
trimmed. Annoying.

My plasma cutter, on the other hand, has an interlock on the trigger
that has to be lifted before the trigger can be pulled.

So, I got to thinking about how to interlock the MIG trigger. I didn't
think of anything that wasn't too complicated, but I did come up with a
guard that's almost as good and very simple:

http://home.comcast.net/~bobengelhardt/MIGGunGuard.jpg

A 1/16" hole drilled on each side & bent wire pushed in. I did open the
gun first to confirm that the holes wouldn't be drilled into anything
functional.

Works a treat.

Bob