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Stainless 6G Question

Posted: Sat Oct 13, 2018 4:20 pm
by FreeTheHousePlants
So, I graduated welding school and have been searching for the right job since. 3 years of "job shops" as they call them around here have been decent work but not what I've been looking for. I finally got lined up for a test I've been looking for and it's a stainless 6g test on 2 inch pipe. In school I practiced 4 and 6 inch carbon pipe pretty good and did well. In the field I've picked up stainless no problem but I haven't done any purge work to prevent the "candying" on the inside. I am hoping that you guys might have some advice on that. And I'm all ears to advice in general. I'm hoping they'll supply legit purging equipment but I plan to bring tape and al foil just in case. I'm thinking to cover up any part that isn't about to be welded in every root pass and set the argon to 9ish on the purge. And for tacking the pipe together I was planning on taping everywhere other than where the tack would be. Is this the right technique? And anyone have any advice on letting the pipe cool inbetween passes? I got a heat gun I've used in the past and have been advised not to let test pieces pass 400 degrees and that worked well for me in the past but I'm not sure if it's overkill. This test is important to me and I have 2 weeks to prepare and am afraid I have nowhere to practice.

Thanks ahead of time!

Re: Stainless 6G Question

Posted: Tue Oct 16, 2018 7:53 pm
by starvncoyote
Better over kill that under kill, but watching Jody on his videos will probably give you the best advice there. I don't do stainless pipe, but definitely watch your heat. Turning up your torch flow a bit more that you would normally have it has helped me. Are you allowed to use backing tape? That stuff looks useful enough to a least look into.

Re: Stainless 6G Question

Posted: Tue Oct 16, 2018 9:14 pm
by Poland308
Tape it up like you described. But remember to put a hole about the size of a 2 pencil in the tape at the top of the pipe. I run my purge at about 5cfm. Give it a few minutes after you start the purge before you weld. Peal back the tape as you work your way around.

Re: Stainless 6G Question

Posted: Wed Oct 17, 2018 6:35 am
by LtBadd
2" sch 40 stainless pipe video on YT, hope this is helpful.

Re: Stainless 6G Question

Posted: Tue Oct 30, 2018 2:28 am
by gnabgib
Yes I've done the carbon steel but in this case I don't think sugaring will be your major problem, more like how to control the heat.