Obviously V-bands are mad for tubing, and not pipe. So what's the best way, or size to match with pipe?

2" Sch10 has an OD of ~ 2.375" (give or take according to specs)

So would it be better to use a 2.25" V-band, and try to sand down the stainless pipe a few thousandths to fit it into the flange..

Or go with a 2.5" v-band and have it slip over the pipe, then weld up the gap with filler?

 

I would just gap it; a 1/16 gap is quick to fill. uniformly removing 1/16" is more time consuming, and you have to weld anyway.

 

Stuff a coat hanger or some sort of wire in the gap to hold it in position then weld away.

ks

 

Either will work just fine. I usually go the smaller of the two, it many times gives you a nice place to butt weld vs a fillet weld. Very clean, especially if you're tig welding.

 

Using filler/wire to center it in the gap is a good idea.

I had thought about using 2.25" V-bands to butt weld it as well. But till probably go with the 2.5" bands because i can get those in a copper o-ring style for good sealing. I'm welding 304 sch40 2.5" to 2" reducers on to my cast manifolds outlet. Then from the fresh 304, 2" outlet will be the v-bands. And the rest will mostly be stainless 321 sch10.

I will be using tig, and 309 filler along with 347 filler iirc for the 321

 

If the gap tends to be too large to weld cleanly make a bunch of slits in the ring then tap them tight against the pipe to close up the gap as you weld.

ks