[ozi jim]

Its all tig.
Tig is way stronger than mig,mig joins by adding material ,tig melts the 2 parent metals together.

With the internal corners you pull the electrode out further and run a little more gas if required.
I can run very short end caps on my tig handle its also water cooled so the handle is half the size of an air cooled handle, so I can run short electrodes to get into tight places'.
I also have another torch that looks like a big pen, it has a swearler in the end for the gas and you can run the electrode out up to 20 mm
The externals is just about running the right amount of amps so you don't under cut.

I use a few more amps than I normally would to get full pen.
If you go to hard the steel bubbles, it must have a higher carbon content or something.

Some welds I just dance over with a sander but I dont grind them back for strength reasons.

Ed I use a band saw to cut the sheets.
Its in pic one.
It is a wood working saw but with bimetal blades it works fine even if a little fast.

Thanks for the encouragement.

Jim