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Up Topic Welding Industry / General Welding Discussion / Help
- - By Tom11980 (*) Date 05-13-2008 11:30
Ok I may not use the right terminoligy but I was doing a reduction from a sch80 flange to fit a sch40 90. I ended up ok a little hi low but ok on top but on the bottom i had gap and hi low.  I got it welded but had to really work at it to get a good root even then it was still a little concaved.  Gap on bottom is hard enough but with hi low? anyone have any sugestions?
Parent - By 1mancrew (**) Date 05-14-2008 01:29
Hopefully I'm understanding you correctly. When you are fitting pipes together of different wall thicknesses try to "transition" the thicker pipe. Take a cone wheel on your grinder and remove a little material from the inside of the sched. 80 so that it matches or nearly matches the sched 40 material. You only need to take out material 1/2" to 1" in on the fitting. This is how I usually do it but if I'm in a hurry I "cheat" a bit and increase my root opening from 1/16" to 3/32". If your getting concavity on your bead pass try decreasing your heat a little bit to just what you need to penetrate. Sometimes a little back and forth whipping motion might help.

Hope this helps a little. Let me know.

GH Weidman
Parent - - By Kix (****) Date 05-14-2008 12:42
How were you welding this? Tig, stick, Mig?  X 2 about the grinding to thin out the sched 80 to fit the sched 40.  Sounds like you had the fitting fit up good on the top, but then sacraficed the bottom. Next time you could sacrafice the top so you have good fit-up on the bottom if you had to.  I tend to split the difference all the way around.
Parent - - By Tom11980 (*) Date 05-15-2008 11:30
Thanks guys for all the input. I am running a 6010 root with a 7018 fill and cap.  I usually try to do that to but with two holing the flange thats were it had to be. I as well got my remote yesterdy so I am hoping that will help alot.
Parent - - By Kix (****) Date 05-15-2008 12:10
How do you two hole your flange, tack, and get good fit-up all by yourself? ;-)
Parent - - By Superflux (****) Date 05-15-2008 14:23
Buy or build an internal clamp. Made a couple out of bolts, but the best have a central screw that expands. This is a good tool to have whether you are working alone or not. Many a time I've wished for a prehensile tail, even with the proper tools available. Sometimes, when all else fails, it helps to bolt the flange to a valve or small dummy/temporary spool (if you have the luxury of working off jackstands). Use the next size larger bolts (flange bolt holes are 1/8" over sized so, many times, i'll just use those instead of 2- hole pins) and hand tighten some back up nuts on both sides.
Parent - - By js55 (*****) Date 05-15-2008 14:42
Match boring the ID is the way to go as suggested, but keep in mind when you do this you will lose take off on your C-bore side. If the dimension from center to face is critical (as they often are with flange 90's) you will need to widen the gap anyway to regain your dimension.
Parent - By Tom11980 (*) Date 05-16-2008 11:20
I see well that helps Thanks guys.  Superflux I did not know they had internal clamps that would be awsome I will look into that.  Yeah I do all the tacking and fit up by myself.  By the way it was shot yesterday and passed x-ray that makes me fell a lot better.
Up Topic Welding Industry / General Welding Discussion / Help

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