Stainless headers with mild steel flange - issues?

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I have been building a set of 304 stainless headers for my car. Given it is relatively old and rare I have not been able to locate a stainless flange. I got lucky and found a mild steel flange. Assuming I weld with the appropriate filler, will I have any issues with cracking or different expansion rates of the different metals? I am unsure if this is a really bad idea.
Reply:So long as you either purge the necessary portions (of SS) with argon or use solarfluxB, you should be ok.  Don't forget to pick up some 309L filler.
Reply:There are folks on this board as well as alot of companies out there that can fab whatever flange you need. All you have to do is provide accurate measurements. But there isn't a prob with mild to SS.
Reply:Some people prefer to use mild steel flanges because they expand less when heated. you can always have someone laser or even cnc plasma cut the flange.Welding/Fab Pics: www.UtahWeld.com
Reply:Thanks for the replies. I decided to hunt down a thicker stainless flange. I found one 1/2" thick which should do the job. Gut feel without being scientific is that given the stainless is a few mill thicker than the mild the expansion should be similar. Using a mild flange was really a crime of convenience.
Reply:Any shop with a decent sized laser or water jet table would have no problem duplicating your current mild steel part in stainless.Vantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:I have built several sets of headers with mild steel u-bends and steel flanges ( the average headers are made of)    Unless you have some kind of weird reason for using Stainless why would you need anything to remove the exhaust that normal headers can't do?    Stainless isn't exactly the best material for hot rod headers and is for sure much much more expensive?Last edited by B_C; 12-02-2012 at 08:51 PM.  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:Originally Posted by B_CI have built several sets of headers with mild steel u-bends and steel flanges ( the average headers are made of)    Unless you have some kind of weird reason for using Stainless why would you need anything to remove the exhaust that normal headers can't do?    Stainless isn't exactly the best material for hot rod headers and is for sure much much more expensive?