V-band flange warped

[dkw_dude]

Hi!
Got a 3" v-band flange welded to my downpipe for my Wagner SPQ manifold/Comp turbo setup , it's quite a bit warped, need to grind off 1,2mm or so
Will grinding it this much be ok, or should I cut off and weld on a new one (this time with v-band and second flange attached)?
Any tips on minimize the warping, my welder is used to thick walled pipes for HVAC applications, so he is open to suggestions..

[blackS2]

Hi!
Got a 3" v-band flange welded to my downpipe for my Wagner SPQ manifold/Comp turbo setup , it's quite a bit warped, need to grind off 1,2mm or so
Will grinding it this much be ok, or should I cut off and weld on a new one (this time with v-band and second flange attached)?
Any tips on minimize the warping, my welder is used to thick walled pipes for HVAC applications, so he is open to suggestions..

Whoha.. I know this issue - I have to grind my flange too but I have not measured it yet... I will try grinding it next time.

I know some guys connect the flange to exhaust housing with v-band clamp before welding the first part of the downpipe - but no first hand information...

[Error404]

It's easy to do - he is putting too much heat into it. Cheap V-bands are worse also, this won't help.
You should try clamping both sides of the v-band together before welding, also work quicker with more amps and keep a really tight arc. Easier said than done.

[dkw_dude]

Thanks for the input guys , what about the grinding question?

Looks like I can get a 100mm belt sander for ~100e in the local "Biltema", think I'll do that and try to grind it flat.

[AndyP]

I use a belt sander to ensure they're perfectly flat after welding but I've never had one warp that much. Put 4 good size tacks on, then weld it in 4 quarters rather than going round in one, this will spread the heat out more evenly

[fish]

It's easy to do - he is putting too much heat into it. Cheap V-bands are worse also, this won't help.
You should try clamping both sides of the v-band together before welding, also work quicker with more amps and keep a really tight arc. Easier said than done.

Also, use pulse function if that is available.. Puts less heat in the material = less warping

[dkw_dude]

Thanks for the replies. Will forward this to my welder. The cheap belt sander was only for wood..
Fish, the Biltema v-band kits, do you know if they are any good?

[terrybullwon]

I use a belt sander to ensure they're perfectly flat after welding but I've never had one warp that much. Put 4 good size tacks on, then weld it in 4 quarters rather than going round in one, this will spread the heat out more evenly

Also, use pulse function if that is available.. Puts less heat in the material = less warping

Alot of sense there

[blackS2]

So, I have done this twice last week:

First one, warped about 0.6mm in two directions


a few minutes before finish (after finish 0,0mm flat surface):


Second one, warped about 1,1mm in two directions


after finish (0,15mm flat surface):


done both by hand

first metal file
after that sandpaper
40
80
120

needed many hours but now it seals perfect...

[blackS2]

Also the Turbo flanges (done after a few minutes):

[martinws]

I have been wondering this for a while as I'm going to be making a new exhaust and wanted to vband it. I was going to mig it with pulse and possibly clamped down to a heat sync of some sort, big alu block maybe.

[dkw_dude]

Good work!
I cut off the flange and got a new one welded on there, with clamp and exhaust housing attached, and welded smaller pieces with a few min pauses to let the heat spread out. Almost perfect result, smoothed it out on the belt sander and it was all good.
See engine bay pic