TomBoctou
Hot Rolled
- Joined
- Dec 29, 2007
- Location
- Boston, MA, USA
Does anyone have any advice for cleaning rust from motor laminations?
For background, a few years ago a friend gave me a really nice Baldor bench grinder (maybe 1980's vintage) that had been submerged (briefly) in a flood. It worked well, but the bearings didn't last long - I soon had to wear hearing protection just to be near it when running. When I took it apart to replace the bearings I was dismayed by the rust encrusted on the rotor, so I took a brass brush and (lightly) brushed it off by hand. I probably didn't have to, except that I was mentally incapable of leaving it there, and I figured having rust powder coming loose inside the motor wasn't actually a good thing.
When I put it back together it ran very slow - probably a few hundred RPMs, very weakly, and very hot.
So I have three questions:
(1) What exactly was wrong? I assume that the laminations had shorted, either magnetically or electrically (those seem to be very similar things when magnets are concerned). Some of the insulated coating must have come off the outside edge of the laminations for the metal underneath to rust. I didn't brush it vigorously, so I don't think I could have removed enough of the insulation to allow the laminations to actually come into contact. Did the rust stick inside the exposed edges of the laminations, making contact with metal on each side, and cause a short?
(2) Was there some way to fix it without going back in time and not screwing with it? I don't remember what I did to clean it afterwards, although I'm generally fond of WD40, brake cleaner, and naptha, so I certainly would have rinsed it with at least one of those. Assuming the problem was the rust in between the laminations, would it have been possible to wash it out? I guess I could have dropped the whole thing in evaporust, since it was toast anyway, but I was pissed off at myself for not being able to stop while I was ahead so I gave it away.
(3) Is there a way to clean it that wouldn't risk making it worse, and, if I can clean it, is there anything wrong with a light coat of clear coat to cover the exposed metal? I now have another motor on the bench with rust on the rotor. My temptation is to hold it with a silk cloth, clean it with a chinchilla hair brush, and clean it by gently whispering "solvent" at it (like the way one puts vermouth in a martini). It's a vintage windshield wiper, however, and lives under the bonnet of an old British car that can't keep the rain out on a dry day let alone a wet one, so I'd like to give it a fresh clear coat to keep future rust at bay, which means some amount of cleaning.
I didn't see another forum covering motors and there seem to be plenty of people here who have spruced up old motors. Sadly the couple of local motor shops I've dealt with in the past are long gone.
For background, a few years ago a friend gave me a really nice Baldor bench grinder (maybe 1980's vintage) that had been submerged (briefly) in a flood. It worked well, but the bearings didn't last long - I soon had to wear hearing protection just to be near it when running. When I took it apart to replace the bearings I was dismayed by the rust encrusted on the rotor, so I took a brass brush and (lightly) brushed it off by hand. I probably didn't have to, except that I was mentally incapable of leaving it there, and I figured having rust powder coming loose inside the motor wasn't actually a good thing.
When I put it back together it ran very slow - probably a few hundred RPMs, very weakly, and very hot.
So I have three questions:
(1) What exactly was wrong? I assume that the laminations had shorted, either magnetically or electrically (those seem to be very similar things when magnets are concerned). Some of the insulated coating must have come off the outside edge of the laminations for the metal underneath to rust. I didn't brush it vigorously, so I don't think I could have removed enough of the insulation to allow the laminations to actually come into contact. Did the rust stick inside the exposed edges of the laminations, making contact with metal on each side, and cause a short?
(2) Was there some way to fix it without going back in time and not screwing with it? I don't remember what I did to clean it afterwards, although I'm generally fond of WD40, brake cleaner, and naptha, so I certainly would have rinsed it with at least one of those. Assuming the problem was the rust in between the laminations, would it have been possible to wash it out? I guess I could have dropped the whole thing in evaporust, since it was toast anyway, but I was pissed off at myself for not being able to stop while I was ahead so I gave it away.
(3) Is there a way to clean it that wouldn't risk making it worse, and, if I can clean it, is there anything wrong with a light coat of clear coat to cover the exposed metal? I now have another motor on the bench with rust on the rotor. My temptation is to hold it with a silk cloth, clean it with a chinchilla hair brush, and clean it by gently whispering "solvent" at it (like the way one puts vermouth in a martini). It's a vintage windshield wiper, however, and lives under the bonnet of an old British car that can't keep the rain out on a dry day let alone a wet one, so I'd like to give it a fresh clear coat to keep future rust at bay, which means some amount of cleaning.
I didn't see another forum covering motors and there seem to be plenty of people here who have spruced up old motors. Sadly the couple of local motor shops I've dealt with in the past are long gone.