Cast Iron repair help

Ive been tasked with repairing a motor end bell. The bell is a C face, with only 3 bolts on the face flange..and it was dropped, breaking off 2 of the three mounting flanges. Material thickness is no more than 1/8" (a very poorly designed endbell). Fitup at this point is good, but Ive minimal room to work as the broken sections are thin in cross section as well.

Ive got good quality 55% silver solder

3/32" Ny55 filler for tig 1/8" Phos-Bronze filler for tig, .035 SS wire (mig wire) suitible fluxes for silver solder suitible fluxes for cast iron brazing Bazooka bubblegum Bailing wire JB Weld Duct tape

Tools:

O/A rig

300 amp squarewave Tig welder

What is the best method to effect this repair?

Ive only got one shot at it and Ive got to deliver it Monday. I knew it was going to be tough..but didnt realize just how thin the motor bell really was...sigh...shrug.

There is really not enough material to drill and pin, unless I use paperclips for pin material....its that thin.

Photos

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flanges will carrying some twisting torque and will be carrying motor body weight. Motor shaft is deeply buried in right angle drive unit so will be fairly well secured from too much weight/torque.

Of course Ill prep by sand blasting/bead blasting the broken bits and the end bell breaks.

Thanks for any advice. Good advise preferred, but bad is also welcomed. Then other posters can pick on you.

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

Reply to
Gunner
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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:

Reply to
Wild Bill

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

1.6mm filler rod..........you will probably find 1/8 is too heavy. k

Reply to
Ken

1) are you sure it's cast iron, and not steel? If it's steel I would tig it for sure. 2) my vote otherwise, if it were mine, would be to silver braze it with the OA rig. Preheat beforehand, if possible. Rig up a brace of some sort to be sure the fracture in the piece 'keys' into parent. Typically when I do this I manage to braze the fixture to one of the parts, but not the two parts together. Don't do that... 3) is there anyway to machine up a replacement ear, that is larger and thicker than the original, out of steel, and fasten that to the motor end bell, again using braze or screws? I would figure not, given the image of the item you've conveyed.

Jim

Reply to
jim rozen

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.

k

Reply to
Wanderer

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

Reply to
Gunner

I once stumbled onto a technique which worked for me. I used a stick welder to apply some nickel filler to the area that needed fixing. I then cleaned things up so they would fit together properly. I then TIG'd (actually flux-cored) the part on. Ernie later told me this is called a "butter pass." The idea is you can use less heat and less filler with a TIG, and you have good control. Steel filler wire sticks fine to nickel.

Reply to
Leo Lichtman

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.

Reply to
Tom Gardner

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

Reply to
Eric R Snow

Surely steel isn't brittle enough to shatter like this? It looks like cast iron to me from the picture.

Good luck with the repair. Let us know how it turns out.

Best wishes,

Chris

Reply to
Christopher Tidy

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

Reply to
Gunner

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

Reply to
Roger Shoaf

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

Reply to
Tony

"There was a problem loading your photos" which may have something to do with me running my computer stripped. But anyway, could not see them.

I'll take it as a given it's cast iron.

Jim

Reply to
jim rozen

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

Reply to
Gunner

Might not be totally crazy. I've seen some pretty small stuff TIGed with Ni rod, by a good welder. However I would pre-heat the item, and it helps to peen it periodically during the process to stress relieve.

For a part like this, I do agree that stick would be a poor choice.

This sounds like a poorly engineered part to begin with though. I suggest you try to think out of the box, and make a repair that's stronger than the original item.

Could you simply drill through the end bell, from the inside, and assemble the machine by bolting the end bell (from inside the motor) to the gearbox, using countersunk screws - and then mounting the rest of the motor to the end bell?

Jim

Reply to
jim rozen

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.

Reply to
Ecnerwal

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

Reply to
ED

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

Reply to
Gunner

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