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Repair of bronze pump impeller

tomjelly

Stainless
Joined
Aug 26, 2007
Location
GA
I need to repair a bronze pump impeller where the pump was run so long that the spring from the seal wore a grove in the seal side deep enough to make a few small holes all the way thru. This will involve building up some material to fill the groove without it draining thru the holes. The part will get bead blasted before repair. Although I probably could use JB weld (this is just a flood coolant pump) I would prefer to use metal, can I use silver solder (HVAC type) or is there a better alternative? I'm thinking the solder will just flow thru the holes& be hard to build. I may have some silicon bronze .035 mig wire I could tig over the holes first if that would plug them so I could fill the groove with silver solder.. Any recommendations or should I just JB weld it?
 

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Its pretty easy to do that kinda stuff with TIG If going the silver solder root may pay to just make up a ring of bronze wire or similar, hell even plain old stripped copper wire to fill in the hole and provide a kinda scafold to then flood with silver solder.
 
Or machine it to parallel sides and flat bottom , then machine filler piece and loctite in place it is captured and spring force will hold it in
 
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I like the wire filler idea, I don't want to machine any more material away as there is not much left there...
 
If you are leaning toward TIG welding you will need to make sure the base material is a lead free bronze. A year or so ago we took in a job welding some adapters in shipboard heat exchanger heads. We could never get the porosity out of the weld. The welds looked good from the outside but were actually full of holes. We also attempted to gas silver solder.
The port engineer had told us the heads were lead free but after tracking down and calling the foundry we found they were C922 bronze. We had to switch to mechanical connections.
Many years ago we used to make some pretty good money repairing worn and pitted impellers with TIG and, maybe by luck never had this type of problem.
Just be aware it can happen.

Walter
 
good info, but I think I'm going to stuff a piece of 12ga wire in there and silver solder it. It wouldn't matter though if it was porous as it is wetted on both sides
 
OK, just cleaned this thing, before I solder it up there is not chance those holes are supposed to be there RIGHT? IMG_20180226_132742.jpgIMG_20180226_132732.jpg
 
that doesn't seem to have much wear for that size of holes that looks factory probably where the water enters the impeller usually when you see holes in a impeller there is no metal left

edit that does look worn through on your dirty photos can you get an idea of what a new impeller of that stile of pump looks like?
 
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It was very worn, as it is I'm going to need to bore the cast iron pump housing for a sleeve for the seal. Everything on both sides of the seal spring wore clean through and ruined both the pictured impeller and pump housing. Unfortunately I can't find a photo of what the impeller is supposed to look like. It would probably be easier to just put a cover on the bottom of the tank and get a submersible pump, but I'd like to keep it stock...
 
Slots there would pull a vacuum on the seal assembly and help it both seal and not leak, unless a jet pump type arrangement i doubt it would effect output all that much if at all, thats hardly a nice impeller to start with. Post up some pictures of the seal, but at this point i would say its 50 - 50 as to OEM or wear, thats very square bottomed, some rotory pump seals i have encounted though did have the springs rest in cut outs like that on the impellor, the fixed seal then riding on the pump motor face.
 
Have you attempted to just BUY a replacement impeller ?

It looks like several I have seen over the years, from standard jet (water well) pumps,
as well as a sump pump or two.
 
These pumps are dirt cheap new. I can't see fixing the thing at all. It will end up costing you at least twice as much to fix it.

Steve is probably right.

If you are determined to fix it I would suggest mounting the impeller on a mandrel. True up the ID, OD, and bottom of the groove. Machine a ring from a similar bronze alloy. Silver solder it in place. Put the impeller back on the mandrel and face the back of it.
 
The parts for this pump are silly expensive. I silver soldered the impeller wear groove with a ring of solid copper wire, completely bored out the housing where the stationary seat was wallowed out, tapped it for a 1" npt brass plug, screwed the plug in and machined it flat then bored for a new seat from a similarly sized generic pump seal from mcmaster carr. $23 fix & 2 hoursIMG_20180306_150012.jpgIMG_20180306_151321.jpgIMG_20180216_172455.jpgIMG_20180309_150108.jpgIMG_20180309_165822.jpg
 








 
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