What stick to use?

[ZRX61]

Or Mig it? I'm talking about welding the breech to the barrel....

http://www.docsmachine.com/nonPB/mortar.html

[Rocky D]

Let me preface in saying I'm not sure, but the strongest rod I can think of is 11018 iron powder electrode...MIG, I dunno if you can get a stronger rod than E70S-6 that's only 70k psi...I'd hate to see it blow up in reverse Certainly would be a good weld test!

[Y2K]

300 cf argon bottles work pretty well, too. I tried to resize a photo, but DUH. If someone can do it for me, I WILL SEND A PIC