exhaust tubing

like to make a jig with many angles so I can make exhaust pipe angle .I have to meg weld and it is stainless pipe . I have stainless wire. I see there's a kit call wrap around magnets but it won't do 2.50 od pipe. I also would like to make a way to back gas my pipe. Some one told me to put a T fitting on my Argon regulator gage. any ideas