Warping Plate (help)

If you were still dealing with the flange alone, you can heat the back side and it will shrink into place. Once you get the tubes on, they usually provide enough strength to hold things crooked. Blacksmith time.

You might try the next set of headers by sett> so i'm welding up (TIG) a custom exhaust header in 304 SS. the tube is 16ga

i did set the tubes in the flange holes as you say. but for support purposes (its a turbo header) i also put a full bead outside..... currently i only have small stubs of tube sticking out.

An example of overwelding is what you have. Stainless has a reputation for distorting more than mild steel. The original welding should have been done with the flange bolted to something substantial like 3/4 inch plate. You might try bolting the warped unit to a heavy plate and applying torch heat to the assembly as you bolt it tight. Heating stainless to a red heat can affect the corrosion resistance. Just hammering on the assembly will likely move the bends around or create a worse washboard effect than you have already. At work we have a flange 3/4 inch thick with an eight foot inside diameter that warped due to some enthusiastic welding.... Wanna trade??? :')) Randy

its a live and learn project. because i dont have much time invested thus far i'll most likely just buy a new flange and try again.

the questions becomes though, can i pre-heat the flange so i can puddle easier, and if so how to pre-heat without causing warpage again??

You could try small welds and only an inch at a time at one connection. Move back and forth over the complete assembly this way until the welding is completed. I think it would be worth the effort to have a piece of very heavy plate with matching bolt holes to fasten the flange to. You could then weld to your hearts delight, let cool and unbolt . Even stacking several flanges together would help. Preheating such a thin section would not make much difference because it would cool off so fast as you were welding. Randy

the questions becomes though, can i pre-heat the flange so i can puddle easier, and if so how to pre-heat without causing warpage again??

yes, but if i bolt it down to another slab of steel how then do i weld inside the flange exhaust holes if a piece of pipe is sticking out? the tube must go inside the flange holes and welded around the inside of the flange hole. i guess i'll need to go real slow. i will also not lay a bead outside, i'll opt for some corner wedges to help support the pipe to the flange.

You could duplicate a manifold flange in heavy plate. That would allow you to have the tube protrude. Another way would to stack extra flanges as I mentioned. If you can at least do most of the welding before unbolting it will help. Another idea is to bolt it to an old cylinder head. You could also bolt left and right manifolds face to face with spacer plates if it was a V8. Our little problem at work is solved for the future flanges by using dogs and wedges to clamp two flanges together then let the welding forces on the two weldments fight each other. Does the flange have to welded to the tubing on both sides??? It sounds like overkill to me. If your tubes are 1/16th thick you only need a 1/8th fillet weld on one side to be strong enough. Randy

snip .

The weld joint with heavy on one side and light on the other is a fatigue crack waiting to happen. It helps to blend the weld off a bit to spread out the stresse of multiple heat cycles.

its not that simple if the tube exiting the flange makes a real sharp turn, aka "cheating the cut".

I guess I could understand that with engine vibration , heat cycling and stainless it would be a problem. Randy

The weld joint with heavy on one side and light on the other is a fatigue crack waiting to happen. It helps to blend the weld off a bit to spread out the stresse of multiple heat cycles.

Try mounting the flange with all eight bolts onto a piece of plate steel. Torque it down good and tight without gasket of course. Start with each tube and get a partner to heat as you bend, markoff, and watch for kinking. Washing the heat all around in little doses seems to do me well. If it's too far gone I'd just rebuild it from scratch if need be. Being such a critical part thing about it. It might not pass tech on some tracks... Think if it leaked and caused a lean condition at 8000 rpm if that turbo lags..That engine is toast... Better off safe than sorry.

All the best,

Rob

there is no heating/bending of tubes. each bend/turn is a seperate piece of tube cut on the bandsaw. each butt is then tig'd.

it's only a $37 part, so i'll start over. this time i'll get 2 flanges and bolt them together while welding to just one of them.

smaller beads and thick steel to bolt to to prevent warping , also preheat the part to help reduce localized heat induced stree

i find it hard to get enough heat down into the thick piece while not having the thin piece melt back and away. the heat from the arc (even though not directly on the thin part) is enough heat to make the thin part melt away, but the thick part did not puddle yet.

Welcome to the wonderful world of performance parts..... It's a bitch. I have so much scrap it's not even funny. It's just learn-while-you-burn. No other way around it unless you farm the job out but that sort of defeats the purpose but sometimes I send off to a "one-off" to a very expensive fab shop on the city but it helps to be honest with yourself with your present skill level. Stuff like that just gives me more drive to learn more... Don't sweat it.

Rob

Fraser Competition Engines Chicago, IL.

preheat , preheat , preheat

really preheat ,

not so easy to do with a piece like this. too much preheat and then the arc adds enough to make it really hot, warp all over again...

Hit the sides with a gas torch. With a helper unless you have a spare pair of arms sprouted out of your back if you live near a nuclear plant.

Rob

Fraser Competition Engines Chicago, IL.