WELDING AND REPAIRING EXHAUST MANIFOLDS

More power to ya if you can do that! I had one on the 45 with a small hole and a slight crack. A guy told me, " no problem, I can weld that." and I believed him for a second or 2. He no more than touched the rod to it and it turned to powder and crumbled away, making a bigger hole.
 Evidently , there are people that know how to do it, but he wasn't one of them.
 I found a new aftermarket manifold and haven't regretted it.

Charlie, I think it depends on the manifold condition... The one in the photo as surface rust, and the hole was caused by freezing.. You can see the metal is in relatively good condition at the hole...... I have also taken an old "B" manifold from 1942 that was rotted out and tried to weld it up.. Paper thin and what is there is like carbon.. no metal to speak of.. Strike an arc and you got a hole the size of a dime.. I think TAD is talking about a manifold ( intake or exhaust) that is in good condition metal wise, just has a hole.

Hi guys, as exhaust manifolds age and are subjected to extreme heating cycles such as a gas engine produces, the cast iron does seem to erode into what I call ash metal,which can be tough to deal with, you can make brass look good and you can make nickle look good but as cast can turn a dull cherry red under load, that means it is reaching the melting point of both brass and nickle and eventually they will lift and separate from the base metal, the newer lean burn engines are the worst for this, in most cases brass and nickle won't stay for long. However, the older diesel engine manifolds seem to tolerate this better than most. One can not argue with someone who has had success doing things a certain way, everybody has their own way, I don't care to use an arc on manifolds, it is done with the square cast iron rods and put on with flame, that is what works for me, it gives a general heating and not a specific concentrated heat area. Sometimes when arc welding high carbon or cast the arc will make ferric carbide, that is an alloy that Rockwells about the equivalent to the hubs of Hades, now that is hard. In these pictures the base metal is actually melted, filler metal added to complete the repair and it can be done on ash metal as well.   Thanks Tad

Very nice work!

Jerbob   I am not a big fan of arc welding on cast especially MIG, but what ever works is considered successful. Is it just me or the camera, does number 4 port look a bit not quite right? cast usually does not move much so I must assume that it is the picture. Have you put a straight edge across the ports or test fit it to the head? You will be making diesel smoke in no time. Tad

Worked in textile mill about ten years . Done most of the welding.Welded hundred parts with torch.Bare cast rod (three sixtenth square x 15)cast iron flux and torch.Use blunt flame .When welded can grind down and look like orignal metal.If it is something like say bowl shaped it is hard to keep from cracking.Exhaust manifold that is burned up you will be wasting time. All carbon is gonne.PS I have also welded alum with torch.

WFMurray, that's the rod alright, boy some of the beautiful casting in those big looms and especially the lace weaving machines is almost unbelievable, very hard for me to conceive how they did it.
Allis Dave  grab a torch and go for it, it is a lot like brazing, if you get it to hot to quick it won't flow well, a very general flame not very close with a bit of blue tail and away you go, of course heat management is the key and the right flux as WF stated brazing flux does not work.  Thanks Tad

You are right about that. Not a one size fits all for sure.