Hey all, I've got access to a MIG now, and Am thinking about starting Exhaust Manifold Mk4 for the lil beastie...

Previously, I've welded the vast "plumbers bends" (weld Els) with NiFe Rods and a Stick (Arc welder)

THinking the MIG may be a bit quicker (and neater!!) is there a secret wire or GAS Combo i need ?

If the elbows are steel then i can just use STD wire and GAS and just turn up the amps a little.... havnt checked yet !!

Cheers all
J

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You are using standard buttweld fittings stamped with a number similar to WPB 234 ?
They are carbon steel, and can easily be welded with the mig, making sure you get good penetration like you said, and let the welds cool slowly - cover with a fire blanket or similar (helps stop cracking later)

Cast iron will not last 10 minutes welded with the mig
unless you use something like a 309 stainless wire, but eutectic rods work best.

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Too many cars, and too little time.

If you can preheat the manifold to good reasonable heat all over and weld it with a stick welder using the proper rods, then heat it up again and bury it in some dry sand or lime or as awdmoke said, a fire blanket, there is a good chance it will work ok.

BUT, it could either last for 1 minute or a lifetime because it depends on the type of and the impurities in the cast metal..

Welding it with a gas MIG wont work ..

Thanks Guys, My Previous Manifold was welded about 3 years ago (Maybe more now) and has covered about 15,000 Miles ... Most of that at a VERY high temperature ...

It seems to have held up well, only one crack and that was my own stupid fault (hey graham!)

Anyway, yep, those are the bends.. Making the whole Manifold from them this time.... bit larger on the ID to help the top-end flow at the sacrifice of the bottom-end ....

Cheers all
J

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from a fella with a vast amount of welding experience:

All the statements above are true

Eutectic (and others) have a metal spray torch which is the duck's gut's for welding Cast Iron.

ALL other procedures are suspect. Extractors are made from carbon steel or at best a CrMo alloy and don't know about Minis or extractors.

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"Show me the Mini!"

I've re-sleeved a shit-load of big diesel CAT turbo turbine housing outlets at my last job using TIG and plain old oxy wire.These housings are a high nickel cast iron and sleeves where mild steel.They take a massive amount of heat,far,far greater than a mini could ever dream of,and still lasted no problems. However,I had to pre-heat the thing.A good trick to this is to heat up your object,get a good amount of spit on your finger and drip it on to the hot job.If it just sits there or boils,it ain't hot enough.Your spit should sizzle and roll off.It's rough,but it's an easy procedure.
Good luck with whatever you end up doing,
Gav

dont talk to me about cat turbo's the only down fall of a great motor c12 and 3406 e lost a few turbo's on them blew flames out the stacks with the 3406e
some one rang the police ambo's and firebrigade and told them my truck was on fire ..... actully a few people on here up newy way heard about it on the the radio in the traffic news .... sorry james for the hijack
makka

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