Cast Iron repair help



You could be surprised. I've reposted this info at least twice. Seems like it's time to do so again, though nobody who has not done it appears to ever pay attention to it (as viewed from lack of replies from people who have not already done it this way ever trying it). Remember that a TIG welder makes a fine stick welding supply, though I guess your Ni55 is TIG rod, which slightly complicates the process (you have to set down the torch and pick up a hammer quickly). Monday is coming fast, but a bit of practice on similar metal might not hurt, as in most welding tasks. Brazing might be fine if you're more comfortable with that.
Cold welding with nickle rod:
Drill the ends and V out the crack - use a narrow (60 degree) V to minimize shrinkage, and leave the back of the crack connected if possible. For this job, fixturing to hold the parts tight would probably help with either welding or brazing.
Use DC-, you should not have a crater (pulling iron into the nickle is not desired) - the manual I'm looking at says there should not be a spray, the metal should fall from the rod in "plops or blobs". Tack about every 2 inches, and then start each new short section on a tack, moving to the cast to lengthen the tacks until the whole crack is covered. Cutting and pasting my own comments from a January 2004 discussion of cast iron repair, with some slight edits:
Use 55 or 99 Ni rod and your stick welder. Weld 3/8 inch, peen the crap out of it RIGHT AWAY, weld 3/8 inch somewhere else on the crack, peen the crap out of it, repeat until done, never get the casting hot. Take a break if you're in danger of getting the casting hot. Very localised application of heat, lots of beating, very quickly, on the nickle to let the nickle move as the weld bead cools, rather than let the cooling weld bead crack the iron. Keep peening until each bead has fully cooled. I personally have only done a little bit of this in class 11 years ago. But the guy who taught me did it, and spent the summers teaching NYS DOT and town maintenance welders to do it, as part of the Ag Engineering school's mission to save the state taxpayers money by educating local maintenance workers. As he explained it, the difference between preheating and not preheating was the difference between (for instance) stripping an engine block, finding or cobbling up a furnace big enough to preheat it, welding on it, cooling it, then putting it back togther afterwards, .vs. cold-welding the crack in place, or at least without needing to fully strip the block. Having both done it and seen it done, I do think it actually works. Welding a stich and goofing off for 15 seconds to find your hammer probably would not work. Trying to hurry the process definitely won't work.
--
Cats, coffee, chocolate...vices to live by

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On Mon, 28 Aug 2006 03:02:41 GMT, Ecnerwal

The THICKEST portion of the metal is 1/8", one chunk is less than 2" long, the other is less than 3".
Of course Ill fixture these in place. The issue is that they are so close to the edges of the bell...
I think Ill try a .040 electrode and phos-bronze on one, after doing what I can to V out the tiny thin edges.
Im running out of time. The motor has to be at the client in the morning..and they have to assemble and deliver it to Their client on Tuesday morning. They of course..waited too long to contact me or a real welder...shrug. shit happens.
Gunner
"I think this is because of your belief in biological Marxism. As a genetic communist you feel that noticing behavioural patterns relating to race would cause a conflict with your belief in biological Marxism." Big Pete, famous Usenet Racist
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I have already told you how to do this job properly..............why bother to ask questions on here if you ignore the answers?
k
wrote:

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On Mon, 28 Aug 2006 06:40:01 +0100, "Wanderer" <www.surfbaud.co.uk> wrote:

I welded it with phos-bronze, after v'ing both the broken out pieces and the main casting. I then sand blasted all the pieces, fixtured them up and using a 1/16th electrode and about 35 amps..heated them up till red, then applied phos-bronze. The braze proceeded nicely, though I experienced some edge melting as I expected, when some of the sections were 1/8" x 1/8" in cross section. I was able build them up nicely.
I then let it cool normally, then put it in one of my lathes, dialed it in, and recut the ID in both X and Z. Thats some tough shit that Phos-bronze. Busted a decent insert right off the start on the interupted cut I took it slow and easy, using a good .75 triangular insert in a big assed solid holder. I then repainted it to match the rest of the motor.
Thanks for everyones advise. TIG brazing works pretty damned well, first time Ive tried it.
As for why did I continue to ask questions...I dont know you from shit. I do know others here, so I got a multitude of opinons, some being good, others being unworkable. Now that I know you actually know something..Ill put you on the "Knows Stuff" list and pay more attention to your advice in the future.
I thank you for your assistance.
Gunner

"I think this is because of your belief in biological Marxism. As a genetic communist you feel that noticing behavioural patterns relating to race would cause a conflict with your belief in biological Marxism." Big Pete, famous Usenet Racist
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Gunner wrote: Ill put you on the "Knows Stuff" list and pay more attention

I wouldn't bother. The poster is a sock of Chris Stevens, usenet nuisance troill and general know-nothing unless he can cut and paste it from google and even then usually get the wrong end of the stick.
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If thats the case then its very very strange that the method of repair recommended, seemed to work very well for the OP!
Glad he didnt try using an Xmas cracker MIG set to bodge the job though.................lol
k
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Wanderer wrote:

Looks like Chris Stevens' kill file has broken. Anyone wanting welding advice would do beter to consult someone whose own scrapyard welding business had :not: failed.
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I have used that method of repair on many occasions, and it really is the best way of doing this type of repair, and if you take things slowly there is no need to mess around with pre-heat and trying a weld repair with Ni rods.
It is also quite possible to build up very thin missing parts with phosper bronze TIG brazing, and to salvage old or badly corroded cast iron parts.
k
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QUICK, go buy a Lotto ticket!
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That would have been good advice, if he had followed your half arsed suggestion for making this repair!
k
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"Wanderer" <www.surfbaud.co.uk> wrote in message

BITE ME!!!!
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I wouldn't suggest something that I haven't done myself already. I've welded thin sections of cast iron before with 99% NiRod, at about 60-70 amps. Sometimes the 55% works good too, and its cheaper. Follow what ecnerwal posted. If the cast iron is weldable NiRod & a ordinary stick welder will do it.
Keep in mind not all cast iron is suitable for welding. Some gray iron welds like crap. Some cast iron may have been made from a wide range of scrap & slag, and may also have undergone heat-treatment such as chilling in the mold. Cast iron that is impregnated with carbon, such as an exhaust manfold, or oil soaked cast iron, can also be a challenge. Cast iron with a high nickel content welds nicely, and cast iron that is closer to a semi-steel will be easy. The wide range of cast iron mystery metals is what I believe causes the diverse opinions regarding the repairs.
Also, proper cast iron repair may require the use of screws or pins prior to welding to add strength to the joint and maintain positioning of the pieces.
The ability to repair cast iron is a important skill to have in any machinist's repertoire.
Tony

2
as
it
welcomed.
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Use of Ni rods is a very much hit and miss process, and whether or not it works is very dependant on the make up of the cast you are trying to weld.
Ni rods do have a use in repair of cast iron, but in this case they are not really suitable. If you have TIG and proper TIG brazing rods, then this process is likely to be a lot more suitable.
k

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Good post, I particularly liked the above sentence, and 'mystery metals' pretty much says it all.
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wrote:
My vote would be to braze it. OA and bronze would suffice. Clean ,vee, fit up tight, use slightly carbarizing flame, heat rod, dip into flux and have a go. Post us a final pix.. ED

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wrote:

Final pics, not assembled. Ill do that in the morning and take a picture and post the entire assembly attached to the gear drive.
I used tig brazing with phos-bronze. First time Ive done this, but it seems to work fine. I tagged the ears with a hammer fairly stoutly and they held. Shrug..works for me. Paint to cover and voila..ugly but repaired.
Gunner

"I think this is because of your belief in biological Marxism. As a genetic communist you feel that noticing behavioural patterns relating to race would cause a conflict with your belief in biological Marxism." Big Pete, famous Usenet Racist
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wrote:

Advice can be good, competent help can be be far better unless you merely need a nudge.
You're outta time to learn technique here.
I could do this job in several ways if you bought it to me. My preerred approach would not be any of those mentioned: it would be O/A welding with railroad rod and Ferro-Flux. That's the technique I use for repair of antique cast iron objects. I never promise success, so far I've never failed ... yet. I'd gladly do that in trade for some training from you in an area of your experise of inerest to me. Distance gets in the way, oh dear. tough shit, nevermind.
I ain't the only show in town, So CA is littered with competence far beyond my primitive capabilities. Find a guy, work a barter.
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Don sez:
"...My preerred approach would not be any of those mentioned: it would be

Con,
Please elaborate a bit on "railroad rod".
Thanks,
Bob Swinney
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Perhaps a child abuser such as yourself is not the right person to comment on something he knows nothing whatsoever about?
k
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Wanderer wrote:

1. Retract that accusation and issue an apology forthwith. 2. Knowing nothing doesn't stop you commenting, does it? (See 1 above).
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