can you polish too much?

[mdwsta4 New User Find all posts View Profile Close mdwsta4]

i repolished some pitted parts of my wheels and it turned out just fine. while inspecting them yesterday it seems like there are a few small parts that appear white. i thought it was left over polish, but i couldn't get it off. it looks like it's underneath the polished metal.
so is it possible to polish too much?

thanks!

[thesound Amateur Metal Finisher Find all posts View Profile Close thesound]

Re: can you polish too much?

You'll never hurt the part by polishing it more: the Law of Diminishing Returns will eventually kick in and you'll get to a point where doing more is just exercising futility. Without actually seeing pics and making an educated guess, the white spots you're seeing sound like inclusions. They're impurities embedded in the casting. Not much you can do about them other than make them as smooth as possible and "blend" them in with the parent metal.

[fly Amateur Metal Finisher Find all posts View Profile Close fly]

Re: can you polish too much?

If the parts are pot-metal then the spots or contamination....and they need to be drilled out before plating....
Pot-metal does like our teeth and get cavities down deep and we have to drill the cavity out.

[mpierich Metal Finishing Guru Find all posts View Profile Close mpierich]

Re: can you polish too much?

If the parts are pot-metal then the spots or contamination....and they need to be drilled out before plating....
Pot-metal does like our teeth and get cavities down deep and we have to drill the cavity out.

LOL...if the wheels are pot-metal he's gonna have a lot worse problems when it's on the road...

[fly Amateur Metal Finisher Find all posts View Profile Close fly]

Re: can you polish too much?

Yep your right, I forgot about what the parts were when I replied. Sorry disregard my 2 cents...

[mpierich Metal Finishing Guru Find all posts View Profile Close mpierich]

Re: can you polish too much?

Yep your right, I forgot about what the parts were when I replied. Sorry disregard my 2 cents...

Haha, no problem, didn't mean to be a [email protected] but I was picturing his wheels exploding...(hmmm, not funny really, is it?).

I wonder if "burning" the metal could make it look lighter in color? Also I've heard it's not easy to polish magnesium, so that's a possibility I guess.

[fly Amateur Metal Finisher Find all posts View Profile Close fly]

Re: can you polish too much?

I found that magnesium is pretty easy to polish, but I just can't get it to plate..I had some side covers on a sport bike that were mag....I think its just the material that was used in the casting, they have different grades of aluminum, like anything else...

[mdwsta4 New User Find all posts View Profile Close mdwsta4]

Re: can you polish too much?

well i didn't take a picture of the affected area, but it's been so nice all week i've been working on some little projects to finish up details on my car. i purchased a set of porsche center caps over the winter and needed to polish them.
they started out like:

then this:

one side polished:

an older picture when i partially polished the first one compared to how it started:

nice and polished:

all ready to roll

my stretch


i'd still like to clean them up a little bit, but they look pretty damn good right now if i do say so myself. definite thanks to nautishine's how-to with the polishing kit. i had no idea how to use it before that. although, i have yet to use the brown compound. i sand, then use black, then rogue, and i finish it up by hand with polish and a MF towel.

[thesound Amateur Metal Finisher Find all posts View Profile Close thesound]

Re: can you polish too much?

Those turned out really excellent. I must say, I'm pretty impressed at the outcome of this project considering it's your first. I'm actually working on a set of wheels now and it's a real eye opener as far as what we tend to take for granted on just about any other project. Another ball that gets thrown into the juggling act when polishing sand cast wheels is that not only do you have to be concerned with the process of smoothing the metal out but you also have to make sure that things stay symmetrical and identical while you're doing it.

I dunno about your experience but I've had the nervous jitters all the way through this project worrying that I'll end up sanding just a little too much in one spot or doing an "oops" that I could otherwise correct on another part but would end up making the wheel look dissimilar to the others. It's definitely a "white knuckles" operation to say the least. My hat goes off to you sir.

[mdwsta4 New User Find all posts View Profile Close mdwsta4]

Re: can you polish too much?

thanks for the compliments. i was bit nervous at first. especially when you begin and the scratches are so terrible! but i just kept at it without much hesitation. i figured if things got that messed up i'd just have to pay to have them fixed. i try to teach the majority of what i do on my car myself so i figured i was up to the task.

[mdwsta4 New User Find all posts View Profile Close mdwsta4]

Re: can you polish too much?

BTW, in regards to my original post, this is what i was referring to:


i don't know how well you can see, but in the corner of the spoke there is a white mark. i know i need to clean up all these nooks that were caked with brake dust from the previous owner, but i'm not sure what to make of these white marks.

[pickleboy Metal Finishing Guru Find all posts View Profile Close pickleboy]

Re: can you polish too much?

BTW, in regards to my original post, this is what i was referring to:


i don't know how well you can see, but in the corner of the spoke there is a white mark. i know i need to clean up all these nooks that were caked with brake dust from the previous owner, but i'm not sure what to make of these white marks.

it could possibly be a intergrainular corrosion. try to sand it out with 240-320 grit and see if you can remove it if you do give it a good shine after if it does not sand out it is a defect in the casting.

[baz Metal Finishing Guru Find all posts View Profile Close baz]

Re: can you polish too much?

just a guess , but that wheel could have been previously painted or clearcoated.
when removing that finish if you have some low spots the clear or primer stayed
in those low spots , by sanding like pickleboy suggested will probably fix the problem