Need a Cast Iron Repair

[Rick_B]

I have a motor end bell where an electrical cover mounting tab has broken - see picture. I'm looking for someone who can repair this using braze/silver solder. I am in the Winstom Sale,m area but am willing to travel a reasonable distance. Thanks
Rick

 

[Charles Lent]

Brazing or Silver Soldering are going to burn up that great paint job. For just a tab that holds the small cover in place I would use JB Weld, assuming that you have the broken piece to attach. Let it harden well, then drill and tap the hole for the screw to hold the cover in place. At least it won't require significant dis-assembly, bearing removal, and repainting this way. It's only a cover and the screw does nothing more than hold the cover in place. Epoxy seems like the safest and least destructive way to fix this. Heat and cast iron are not a good mix, and more often than not, more destruction rather than repair is the usual outcome.

Charley

 

[Rick_B]

Thanks Charlie - you make some good points. In this case the motor is already disassembled and I can easily repaint the one end bell. I worry about JB Weld in this application - I haven't had good luck with it holding things like this

Rick

 

[tghsmith]

repairing cast can be problematic,, I also would also go the JB weld route.. but add a washer to the back side to help support things,,

 

[Rick_B]

repairing cast can be problematic,, I also would also go the JB weld route.. but add a washer to the back side to help support things,,

That's a good idea

 

[Martin Roper]

If clearance isn't an issue, I'd be tempted to grind off those stubs and make a new tab. Replace the tab with an oval piece of metal with two holes drilled into it, one for the mounting cover and one for a nut and bolt.

 

[Rick_B]

If clearance isn't an issue, I'd be tempted to grind off those stubs and make a new tab. Replace the tab with an oval piece of metal with two holes drilled into it, one for the mounting cover and one for a nut and bolt.

View attachment 237416

Anoher good idea

Rick

 

[Wiley's Woodworks]

Another vote for JB Weld. To get maximum strength from the epoxy, fill in the hole. You can drill it out afterwards. Also, wire brush clean the edges of the break.

 

[Rick_B]

Working on the solution from up thread - JB Weld and a washer - I'll report back when I know it works

Rick

 

[RRR]

Working on the solution from up thread - JB Weld and a washer - I'll report back when I know it works

Rick

I would try JB weld and if it fails you could always braise or silversolder a tab and retap the screw hole. If you go the braising or silver solder method the case should be heated and cooled slowly which will discolor and ruin the paint but can be repainted.I could coach you through it if you need

 

[Rick_B]

I believe I have successfully repaired the broken mounting tab. Fortunately the broken piuece of the tab had enough threads that allowed me to use a screw for alignment.



I used the screw to align the broken piece and a small washer. I used JB Weld to attach the washer to the broken tab piece. After that cured I again used the screw to align the broken piece with the remaining end bell threads and used JB Weld on both the cracked area and the exposed section of washer to provide some support under the broken piece.





It seems to work fine and feels like a strong bond. I did have to run a tap through the hole after the JB Weld cure. I suspect some epoxy got into the threads.

Thanks for the suggestions
Rick

 

[charlessenf]

I believe I have successfully repaired the broken mounting tab.

Much easier than welding!

 

[Rick_B]

OK - I jumped the gun on the broken tab. It appeared pretty strong but when I was assembling the cover the screw was not sitting straight and when I gently tried to align it by screwing it in - the %^&*%#%^ broke off again. I think the problem is there is no good way to clamp the joint as the JB Weld cures and not enough surface area. So I a still looking for someone who could silver solder this piece

Rick

 

[charlessenf]

"looking for someone who could silver solder this piece"

The video I found online demonstrated a CI Repair using nickle rod in an arc welder.
Of course, just because "I saw it online" doesn't make it right. 'cus I just found this there:
What is the best repair for cast iron?
Bacon grease is the best, and when you have nasty cast iron, a lye bath will restore it to like-new condition.Sep 13, 2021

Is there a reason you're specifying a repair using silver solder?

It appears to me (and, I suspect you've found) that holding that tiny tab in proper alignment while performing any sort of activity involving heating the two parts (evenly) while depositing flux and silver solder, or brass brazing rod, or filling with nickle arc welding rod is a low probability of success operation.

If you watched the video I found, you would have noticed that the machinist did not attempt to preserve the existing threaded hole. Rather filling it in (nickle rod), machining the surface, drilling the hole and then tapping it.

That sort of approach seems feasible, but involves a bit of machining best accomplished with the right surfacing tool, etc.

I have a set of tanks as well as an old "Tombstone" Stick welder and a little MIG outfit, but no experience with Cast Iron and no machining tools beyond files, grinders and drill bits. And I definitely don't had a welding rod heating oven!

 

[Rick_B]

Charles - I have no equipment, material or skills to weld anything let alone cast iron. I say silver solder because I have been told it takes a lot less heat then welding. My only exposure to welding is as an observer. I do know that it takes a very controlled heat and cool cycle to avoid distortion. I have had a guy who knows what he is doing damage a drill press head by welding and that wasn't the first one he had done. Given that the only thing under that cover are two wires to reverse the direction I would likely put duct tape over it before attermpting welding.

I do appreciate your comments

Rick

 

[Rick_B]

so I have been offered a used end bell that matches perfectly - what are the thoughts on interchanging the end bell? Are the end bells typically matched?

Rick

 

[Charles Lent]

If for the same motor by frame number, it should be a direct replacement. Try it out before going to the trouble of painting it.

Charley

 

[bob vaughan]

In theory, yes, but the bore for the bearing may vary so a shim or two may or may not be needed to keep the armature from sliding back and forth. If your motor is an RI, then maybe the brush holders will bolt right up or maybe not, depending on the RPM of the motor.
About all you can do is try.
If it is a 3-phase motor, you should be good. Nothing bolts to the end bell.

 

[Rick_B]

In theory, yes, but the bore for the bearing may vary so a shim or two may or may not be needed to keep the armature from sliding back and forth. If your motor is an RI, then maybe the brush holders will bolt right up or maybe not, depending on the RPM of the motor.
About all you can do is try.
If it is a 3-phase motor, you should be good. Nothing bolts to the end bell.

I wish it was 3 phase Bob. It is single phase, dual voltage, 1725 RPM, capacitor start. So there is a centrifugal switch to deal with.