The Stovebolt Site Forums The Shop Area General Truck Talk Welding cast iron.

Just saw a good video of welding cast iron with Muggy weld 77 electrode using TIG. This was on Yanmar cast iron, not so old, but worth trying on some old('40's/'50's).

Ed

I weld but will not claim to be a welder. I just watched a video of a professional fabricator weld a cast dual on a oem cast exhaust with a mig and regular 70s steel wire. The cast was heated to red hot them migged before it lost the red.

I have heard of heating before using a nickle type stick rod or using a cast iron stick rod -- but not a mig with hss. Probably not unheard by most of you.


https://www.hotrod.com/articles/195...-cylinder-exhaust-manifolds-the-old-way/

Welded at a shipyard a few yrs. Used to (gas) weld cast with stainless rod. Stopping frequently
to peen it with the pointy end of my "pecking" (slag) hammer. Worked a champ.

--Chris

I found a spool of nickel-alloy wire for my MIG machine on Ebay, but I haven't gotten around to trying it out on anything yet. It's fairly large diameter (.045") so I'll probably have to turn the heat up a couple of notches. I'll probably do the preheat- - -weld- - -peen-- - -post heat process, then bury the part in a pile of sand to cool down slowly.
Jerry

I might try my hand at welding a 1955 cast iron exhaust manifold. The PO somehow broke the flange off of the output side.

I've used silicon bronze rod for tig almost letting it bleed into the crack works very well. Will have to try one of those rods apparently no preheat is required.

Oh, you're gonna *love* that stainless. When you get a chance to burn it, Jerry!
Capable of making the most beautiful beads you've ever seen. It makes
those who can't weld, look good ( no insinuation(s)! ).

--Chris

I've burned a LOT of nickel rod with an old style Lincoln AC/DC stick welder. Just about every vocational education shop I worked in for 30-something years had one, and I taught a night class for beginner welders for a few years. I really prefer a torch and brass to make repairs on cast, but some applications work better when they're welded. When I was a maintenance mechanic/welder/pipefitter for E & J Gallo Winery in Livingston California, one of the oldtimers in the shop and I repaired the bowl of a huge centrifugal pump that had shelled out an impeller and put a 6" diameter hole in the side. We scavenged up all the broken pieces and put it back together like a jigsaw puzzle. It took about a week of fitting, tacking, and welding.
Jerry

Nice work! Agreed, brass is probably a better choice. But I haven't had an opportunity
to put the comparison to the test. So I'm really only qualifying that statement based on
the fact that *that's* just the way it had *mostly* been done. The best verdict I could
provide is they both seem to be adequate. Most of my cast work was repairs to fishing
vessels that had skippers that were too cheap to replace a failing/abused exhaust manifold.
Speaking of ship yards. I used to weed out the BS newcomers by asking them to get the
keys to the sea chest, and see how many attempted to find them. What a hoot!

You know I *did* say "no insinuation".

--Chris

Does brass handle the heat of an exhaust manifold well, or does the heat get to it?

Ed

Since brass (or more appropriately) bronze-alloy rod requires the base metal to be heated red before it will bond, unless there's a really lean cylinder or two causing the manifold to glow, braze repairs stay put very well. Brass is also less likely to create stress risers at the edge of the repair and cause a crack to form beside the weld bead like nickel rod does if it's not properly applied. Brass flexes during the heat cycling that an exhaust manifold experiences during warmup and cool down every time the engine is started. The main concern is getting the base metal really clean to allow the brass to get a good bond to the casting. Some poor-quality cast iron has so many impurities in it that it's impossible to either weld or braze- - - - -just scrap it and find another part!
Jerry

Thanks Jerry, good explanation.

Ed

Must be a common problem. I have one here with the same missing flange ear. Around 1979 or 1980 I saw a fellow fix one with what looked like a 3/4 inch wide piece of 1/4" thick angle iron. He drilled matching holes in one side of the L and the manifold but not all the way through, threaded those holes in the manifold, letting the bottom of the L sit on the little ledge left when the ear had broken off, attached the piece with short screws, drilled and threaded the angle iron for his stud and rounded off the end to look more like the original. Can't be certain, but I'd guess he used 1/4" screws. The way it sat and the way he had shaped it the fix looked ok and he said it worked just fine. Just an alternate thought.