Cast Iron

[Brainfarth]

I've welded cast iron quite a few times in the past via NiCad rod, brazing and thermal spray. I've read that cast iron likes to absorb carbon over time and can be tricky to weld(like headers and stove doors). I had to repair a stove door and had a heck of a time keeping it from cracking out, but the NiCad rod pulled it off with short welds(1" or less) spaced apart and let cooled down before welding more. But not too long ago a customer brought in a cast exhaust manifold with a big crack in it and wanted it welded. So I ground out the crack and tried to weld it and the cast almost bubbled away from the weld(brazing is not an option for metals being used in 500 degree invironments or greater). I tried some s.s. rod with the same results. The end result was a stinking mess which the customer didn't care for much and the part was rendered useless. Has anyone successfully welded old cast manifolds?

[ripcurl]

How much preheat did you put into it ? Ususally that is the trick with most cast parts.

[vipermanz]

what about tapping it with a hammer after welding to pre stress relieve?? when i tig'ed a piece of cast just for fun that's what i did. Cleaned it, heated with torch, then tig'ed with no filler, tapped with hammer while it cooled

[Sberry]

Hey, its a mystery. I have welded some you though would never have welded they were so dirty,, welded right up, another one looked good,, weld terrible. The worst one I ever did was an old tractor block. It wouldnt weld for anything and I tried it all. I finally JB welded a flat strip over it and it has been fine ever since. Every once in a while you get a bummer and there doesnt seem to be much you can do about it. A lot of times on the bench where you can stay flat it helps to run on AC if it tends to arc blow, but that bubbling, turning to sand look,,, I certainly cant help you with. Been there, done that. I can feel your pain bro,,, hahaha (even though its not really funny) But,, as to answer part of the question,,, yes, have welded several of them, usually it works.

[Brainfarth]

I think I'm going to have to start turning people down that come in with manifolds.. Or just have them sign a disclaimer of somekind. Just when you think you have a grasp on things, something like this puts your in your place....

[Sberry]

I welded one a while back that was ugly and I thought it would have never worked by the looks of things. What a suprise. welded up just fine,,, its definately weird at times. It can be as finicky as aluminum. I hate welding cast with a passion. If I never had to do either one it would be fine by me. So many potential problems. Great thing about mild steel,, ha,, it always works.

[Brainfarth]

Given the choice, Aluminum is my pick. It's so easy to work, cut, prep and weld. You can tell that I've been working aluminum that day when I'm still clean after work. ;) Yeah, steel dosn't like to gripe much either, but it seems to throw oil and smoke all over me.

[Sberry]

I try not to work that hard if I can help it,, hahahahahaha

[gimpyrobb]

O.K., while I'm helping a buddy put a large compressor pump on his tank, he decides to take the pulley off the motor. The pulley snapped off a chunk. The replacement costs 80.00+ at grainger. Their web site states that it is made of "Durable SAE G3000 Cast Iron". I'm wondering if its possible to weld since we know what type of metal it is. Here's the grainger page.
http://www.grainger.com/Grainger/productdetail.jsp?xi=xi&ItemId=1611578343&ccitem=
I hope this link works to pics of the pulley:
http://pg.photos.yahoo.com/ph/gimpyrobb/album?.dir=/7252

[rockytopp]

Well I have done quite a few manifolds, used to work for Midas, at that time all we had was a torch. so braze we did, never seemed to have much trouble looking back. I still do one once or so a year. Stove cast was and is the worst, its a very dirty type that is used for stove. rather like unto bed rails,,, some you cant cut with a saw and move two inches and it melts through it..... dirty cheap mix of steel... cast the same. I wonder , we used blue max on some cast the other day after nicad did not work,,, it finished up and was great,, any one else ever done cast with blue max?.. works for us.Just had to throw my two cents in... thanks. :waving:

[gimpyrobb]

Do you mean the blue max stainless mig wire?

[rockytopp]

No, this is stick, I assume that blue max is brand, I purchase it from our local welding shop. The flux is blue, the rods I use are numbered as follows. Blue Max-2100. 578B Blue Max. The 2100 is 1/8th and the 578B is 3/16th. It flows like butter and is very easy to work with, and does a great job for us at home and in the shop. only draw back I can see is the cost and that is rather pricey.