So I cleaned my guitar and I noticed that 6 of my magnets have some weird black dots on them. I think it's the coating or rust. The one on the picture is the biggest, rest is much much smaller.

Is this a problem? Am I able to replace single magnets or do I have to purchase the entire thing? Perhaps it can be fixed? Thanks in advance.
Last edited by TheNaitsyrk at Sep 1, 2015,
Probably just some oxidized stain preparing to rust. You can just use a qtip and put some metal polish to scrub it then wipe away.
it's a result of the pickling chemicals not being entirely rinsed off of the poles or a tiny amount that contaminated that pole before plating. often shows up as a small blister with black oxidation underneath.

at the day job we do a lot of nickel plating of large electromagnets and I see this fairly often. a weak solution of sodium bicarbonate can be prepared, wiped on with a q-tip to neutralize the acid. when dry, you can then apply some ca glue to seal up the area.

more then likely you'll never have to do anything and your guitar will be fine. if you do decide to do something about this, it's delicate work and you need to be steady with your hands and thrifty with your chemistry and glue.
Last edited by ad_works at Sep 1, 2015,
So metal polish will not work? And the black spot appeared because someone didn't wipe the chemicals before plating? Aww...

Will I be fine without doing anything to it? I don't want black spots to become bigger.
Last edited by TheNaitsyrk at Sep 1, 2015,
imo, i would get some baking soda and water mix up a weak solution. then dab the edge of the pole with the q-tip just enough to get the area and no more. you don't want water running down the pole into the coil. let it dry, wipe it off, then use your metal polish. simichrome is a good choice.

honestly i think you will be fine. if it's what i think it is i can't say that i've ever see it get worse unless you immerse it in water repeatedly for a long time.

plating of pole pieces like that is done in large batches and humans rarely touch the stuff as most of it is semi to fully automated. the chemistry is rinsed off in large tanks with minor agitation and then moved on down the plating line to the next tank. plating is nasty, ugly, dangerous business and most of the folks i've known who worked in it seem to have large volumes of brain cells missing from inhaling chemicals and their work cloths have tons of acid holes in them.
Last edited by ad_works at Sep 1, 2015,