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Discussion Starter · #1 ·
I've tried just about everything, yet some areas are tarnished with discolored, dark spots. (see pic)

I've tried steel wool, scotch pads, ultrasonic cleaner, lacquer thinner, just about everything.



is there a trick or something to get rid of these?

The only thing I've done which worked (but takes forever) is a light sanding (with 600 grit paper, then finer, then up to 1800, to polish)though, this will be very difficult with many of the harder to reach areas.



 

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Others may have easier ways for you but here is mine.



Rub the whole part down with 120 grit wet and dry until all the dark pits are gone and then work your way through progressively finer grades to at least 800 grit [up to 2000 is better] then polish with metal polish. Tedious, but works very well.



OR, you can have the parts bead, soda or vapor blasted.
 

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Discussion Starter · #4 ·
Others may have easier ways for you but here is mine.



Rub the whole part down with 120 grit wet and dry until all the dark pits are gone and then work your way through progressively finer grades to at least 800 grit [up to 2000 is better] then polish with metal polish. Tedious, but works very well.



OR, you can have the parts bead, soda or vapor blasted.


I was afraid of that. seems to be the only thing working. curious, is bead/soda/vapor blasting expensive? say I just wanted 2 valve covers done...?





If the part is small enough and you have it off the bike, use a fine steel brush on a bench grinder.


I've tried the steel brush, does nothing. Even tried the steel brush bits (several types) with my dremel, did nothing.
 

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I have no idea of the prices of the blasting methods. I used to do blasting for a job 20 odd years ago but never handled the pricing.



If you have a large compressor you can do the glass beading at home, a 20 kg. bag of beads would probably set you back about $50. AF or AG grade is generally best for this sort of thing but while it removes the corrosion from the pits the pits themselves still remain.



I still do a bit of bead blasting at home when neccessary but mostly use the wet and dry paper method.



If you polish the parts I reccomend not clearcoating. The corrosion pits are generally caused by chips in the clearcoat, allowing corrosion/oxidisation to spread underneath. Without the clearcoat you can give the parts a quick repolish every few months and keep the nasties away.
 

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Discussion Starter · #6 ·
I have no idea of the prices of the blasting methods. I used to do blasting for a job 20 odd years ago but never handled the pricing.



If you have a large compressor you can do the glass beading at home, a 20 kg. bag of beads would probably set you back about $50. AF or AG grade is generally best for this sort of thing but while it removes the corrosion from the pits the pits themselves still remain.



I still do a bit of bead blasting at home when neccessary but mostly use the wet and dry paper method.



If you polish the parts I reccomend not clearcoating. The corrosion pits are generally caused by chips in the clearcoat, allowing corrosion/oxidisation to spread underneath. Without the clearcoat you can give the parts a quick repolish every few months and keep the nasties away.


thanks. I'm gonna keep at them with sandpaper. it's not that bad. removing the original clear coat was a pain.
 

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Haven't read everyone's response to you so not sure if this is a repeat or not but the ONE thing I noticed is that you're starting out with 600 grit sandpaper which just is NOT coarse enough....you gotta start with 320 which will usually get about anything off and maybe down to 200 grit IF needed.



Then of course work your way up the grit chart to about 800 then steel wool to get all the little scratches out that the coarser sandpaper left.



EDIT: If you were nearby I'd say bring it on over dude, let's have at it....EVEN THOUGH you're probably a Yankees fan living in Jersey, I'd overlook that little transgression.....
 

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Discussion Starter · #9 ·
Haven't read everyone's response to you so not sure if this is a repeat or not but the ONE thing I noticed is that you're starting out with 600 grit sandpaper which just is NOT coarse enough....you gotta start with 320 which will usually get about anything off and maybe down to 200 grit IF needed.



Then of course work your way up the grit chart to about 800 then steel wool to get all the little scratched out that the coarser sandpaper left.


luckily, my line of work has put many types of sandpaper in my shop. I've had great results starting with 600, then moving up to 1000. The harder to reach areas - I'm rolling the sandpaper around a stick, and it's getting most of that stuff. Will go back over everything with a 1200 or higher to remove the (hardly visible) scratching, then a polish.
 

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Discussion Starter · #10 ·
well, thought I'd share my progress again.



have had amazing results using a wire brush bit on my dremel. Only at a high RPM, I am able to cut right through these spots, and leave behind a nice shine. I was able to do the entire valve cover in about 10 minutes. Right now, the cover's in the ultrasonic cleaner, which I hope will pull all the sanded residue off. After that, I will hit the entire part with 1000 grit sandpaper, then something even finer, then polish.



 
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