How to Get Flange Perfectly Flat

[scratchedup]

This is a 3" V-Band set up. It got ever so slightly warped during the weld up.

What is the best way to gently get a perfectly flat surface....Surface Plate with sand paper...chuck it up in a lathe......?





THX

 

[t100]

there are different ways to do it. just remember you don't have to have them perfectly flat, the band will pull them together.

#1. get a 3rd flange and lock the band(assume there's no plastic/rubber in the band)

#2. get fittings with longer tube, so your welds are further away from the flange.

#3. crank up the welder, higher amperage, faster welding speed and only weld about 1.5" at a time. dunk it in a bucket of cold water to cool it and weld again.

some times you can sit the fitting in a bowl(stainless steel bowl) of water after tacking it up, use the water to cool the parts. but it may cause hydrogen embrittlement.

btw, your weld looks kinda cold.

 

[scratchedup]

there are different ways to do it. just remember you don't have to have them perfectly flat, the band will pull them together.

#1. get a 3rd flange and lock the band(assume there's no plastic/rubber in the band)

#2. get fittings with longer tube, so your welds are further away from the flange.

#3. crank up the welder, higher amperage, faster welding speed and only weld about 1.5" at a time. dunk it in a bucket of cold water to cool it and weld again.

some times you can sit the fitting in a bowl(stainless steel bowl) of water after tacking it up, use the water to cool the parts. but it may cause hydrogen embrittlement.

btw, your weld looks kinda cold.

thx...no o-ring......next time i will get the one with an o-ring

 

[ezzzzzzz]

I used one of these on the s/s exhaust system for my 240Z. Don't worry about the slight warpage. It will seal up nicely with the band and a bit of carbon buildup over time.

 

[scratchedup]

clarification-
This is an aluminum piece. 3" OD from IC to TB.

 

[steel 35]

My two cents, Just clamp it. For the future clamp two together while welding.

 

[dlcwent]

My two cents, Just clamp it. For the future clamp two together while welding.

^ good plan. It's what I do. It eliminates the guess work and "tipping" of the pipe when heat is applied to one side. JMO

 

[RoosterBooster]

i used a wide belt sander on all my Turbo/CC/WG flanges
some elbow grease and a sheet of sanding paper on a surface plate would probably work just as well

i did not use any gaskets (except a high temp metal one between turbo and exhaust manifold)
a exhaust/turbo fabricator told me to spray high temp exhaust paint on each surface before assembly ....
i dont have any leaks (and no chance of blowing a seal out) ... but i have only about 3000 miles on the turbo

 

[srmofo]

i used a wide belt sander on all my Turbo/CC/WG flanges
some elbow grease and a sheet of sanding paper on a surface plate would probably work just as well

i did not use any gaskets (except a high temp metal one between turbo and exhaust manifold)
a exhaust/turbo fabricator told me to spray high temp exhaust paint on each surface before assembly ....
i dont have any leaks (and no chance of blowing a seal out) ... but i have only about 3000 miles on the turbo

I always used copper seal at those joints

 

[NKlamerus]

I ran close to the same thing on a 2002 Duramax. EVERY shop said any v band clamp will leak; nature of the beast kinda thing.

I'm glad to know there is other options out there

 

[Kevin54]

This is a 3" V-Band set up. It got ever so slightly warped during the weld up.

What is the best way to gently get a perfectly flat surface....Surface Plate with sand paper...chuck it up in a lathe......?

You hit the nail on the head. Either one of those will work just great, Either double side tape some sandpaper to the surface plate, and work it down to flat, or if you know that you can get it into a lathe and run fairly true, then go that route.

I'm assuming that you have some machinist background?

 

[A_Pmech]

Yup! That's what those cheap 8x12 chinese surface plates are good for. Perfect size for a sheet of sandpaper and no worries when the plate is toast. Throw it in the creek and buy anther one!

 

[quietsailor]

I used to work at sea and there we'd use waste porthole glass placed on a flat surface (for support) plus grinding paste.

Then we'd put move the part in a figure - of - eight motion so you got an even grind across the full surface

 

[MoonRise]

Lap the flange faces on a piece of glass or a 'cheap' surface plate.

No need for double-stick tap or anything, just put a piece of wet-dry sandpaper of the desired appropriate grit right onto the 'flat' surface item (glass is usually flat enough for non-critical uses, a cheap surface plate is more than flat enough) wth a bit of oil/water (whatever you are using for 'lube') between the sandpaper sheet and the flat surface. Surface tension of the liquid (oil or water) is usually plenty to keep the sheet in place during lapping.

 

[scratchedup]

It looks to be about 3/64" out ...worst case. Any suggestions what grit sand paper to start with...I thinking 220?

 

[yhprum]

Another good surface plate is a granite tile.

 

[FlyingLow]

I wouldn't put it on a lathe unless the flanges are dead square, you'll make the flange to thin on one side. 180 or 220 sandpaper would be a good start.

 

[theknurl]

I'd use my 16" Apex disc grinder, 30-40 seconds......done

the weld is cold....crank it up

next time use a rotary table, tack it 3 times .....

don't cool it off, the tacks work as preheat

don't even use rod.....burn the flange down and into the tube

that weld will look like a skinned flattened chrome earthworm

welding for 59 years

 

[Sticky Grips]

I would use a block of wood and sand paper to square it up. Also...I've found that having a piece of piping sticking out of one v band helps drastically in line up and sealing.

 

[sqznby]

My two cents, Just clamp it. For the future clamp two together while welding.

This

Weld them clamped together and let them cool down clamped together.


Leave them as is, no need to do anything else.

 

[scratchedup]

Sun in back ground.

THX for all the help.....

 

[A_Pmech]

Looks good!

 

[Daniel Dudley]

I always used copper seal at those joints

Or blue Hylomar. Nice job !