Cast Iron repair help

My choice would be O/A torch and braze, because I have more experience brazing, and I don't have a TIG welder. Secondly, I think the torch flame would tend to gently heat the part and the repair could be accomplished at a lower temp. Torch heat and brazing is a good approach with small parts in this range, or slightly more mass (up to maybe 4x as much). After that larger sized workpiece size, I think preheat and TIG or arc would be better .

If it were me, I'd try to come up with a way of holding the pieces closely together that wouldn't interfere with the repair. After the pieces are secured, I'd clean out the repair lines, while trying to V into the thickness just a tad, at the break lines. I'd proceed with heat and fluxed brazing rod, adding some extra build-up anywhere it can be added, maybe inside and out (can't see the opposite side). Some thickness build-up would be good IMO, because you'll need to remove some of the filler material (filing maybe) where the motor case fits closely in the shoulder area.

If you're uncertain, you could do one "ear" and wait till it cools, listening to the part as it cools. The rice crispies sound wouldn't be a good sound, but check the area with a magnifying lens to see if you want to proceed with the brazing.

I'd be surprised if there isn't a crack at the third mounting hole "ear".

If all else fails, you've got all day to machine a new part.

WB ..............

Gunner wrote:

Have repaired quite a lot of cast iron similiar to this, using TIG brazing. You need to go very slowly, and try not to get it too hot. I always use

Using a MIG to repair cast iron, never usually works out as well as using TIG brazing. However as the OP doesnt have a cheap MIG, I doubt very much he will be wanting to buy one in order to find this out.

Well...I do have a 200 amp Dan-mig and a 350 amp Airco PhaseArc 350..but didnt figure either of those the proper tool for this job....

Im listening....

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

Sucks to be you! I'd go for the OA braze after tacking the parts together with spots of MIG, "V" cut the cracks, fill the "V"s then break off the MIG spots, "V" cut those spots and fill with braze. Plan B: machine new bell.

Greetings Gunner, I have some rod made by Stoody cxalled "Castweld 55" It's for stick welding. It will weld cast iron to steel. I used it to weld the gear case on my Bush Hog to the surrounding steel framework. The gearcase mounts had all broken. The repair is now about 3 years old and has at least 20 hours of really hard use since the repair. No evidence of pending failure. So your Ny55 is probably the same stuff without the flux coating. It looks to me like you can build up the area. If it was me after prepping the part I'd build an oven out of fire brick and heat the part up with a torch. Then TIG weld it with the Ny55. Weld both sides of the break if you have the room and leave the weld proud. Cover the part and let it cool slowly. I welded the cast iron engine block on a 1945 Wisconsin 7HP engine with silicon bronze TIG rod. The block broke through the bearing bore for a Timken tapered roller bearing. This bearing is at the flywheel side of the engine. That repair is at least 7 years old and has too many hous on it to count. I welded it using the firebrick oven method. I don't know how well phosphor bronze rod would work, but the silicon bronze rod sure worked well. ERS

The end bell is about 5" in diameter ( I knew I should have included a ruler)..and as I said..the thickest portions of the break is about 1/8".

So this is thin. The inside of the bell is machined to fit Over the body of the motor, so will have to be remachined or ground with a die grinder to fit back on the motor body.

Preheating is not an issue..Ive got hot plates, rosebuds, propane torches etc etc. Ill have to figure out how to get the rubber shaft seal out though..

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

One thought, did you check to see if a replacement was available? That might be the best solution if it is chap and available.

Get some NiRod 99% nickel welding rod from any local welding supply or MSC and a stick welder. No preheat necessary, works A/C or DC, I prefer DC.

Tony

Somehow I get the feeling that hitting a tiny piece of 1/8" thick cast iron with a welding rod..particularly a nickle one..is not gonna leave much of those ears.

But thanks for the suggetion.

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

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.

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

The plain truth is that much cast iron damage cannot be repaired economically.

In the welding business, many customers make the incorrect assumption that a repair is less expensive than a replacement part. There is a place for cast iron repair for parts which are very expensive or very old or where replacement parts are just not available in a timely manner. In an industrial operation a repair often only needs to work until the replacement part can be obtained and repair cost is a relatively minor factor compared to downtime.

It takes time to properly disassemble and degrease and prepare and clean and preheat and weld slowly and post heat and cooldown and cleanup and reassemble and do the paperwork, all of which is done on billable hours. My advice is to always estimate/quote high and never give a guarantee on cast repair.

Cast iron repair is more of an art than a science and its success depends to a great degree on the quality of the iron and on luck and the skill and experience of the tradesman.

There are many different types and qualities of cast iron and while some poor quality cast is very difficult to repair some good quality cast is really cast steel and can be repaired quite easily. Just because you have a procedure or technique that worked before does not mean it will always work.

Good luck, YMMV

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

I have already told you how to do this job properly..............why bother to ask questions on here if you ignore the answers?

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.

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

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.