Author Topic: Polishing rusty chrome  (Read 392 times)

Offline Ken4004

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Polishing rusty chrome
« on: November 13, 2025, 10:35:18 AM »
I have just seen this video about a guy in the States re polishing a rusty chrome mudguard, looks interesting although at the start he uses fine emery cloth to remove the rust before he starts polishing.
I would not of thought of using emery on chrome because I thought it is a very thin layer and wouldn’t take much to rub through .
Has anyone else used this technique on chrome ?

https://youtu.be/Ss7CfT41HzQ?si=3klvVXY8IiOcfr8p

Offline Ken4004

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Re: Polishing rusty chrome
« Reply #1 on: November 13, 2025, 10:40:37 AM »
Sorry I make a mistake he used 00 wire wool , mixed this video with another I have been watching whoops, but I think wire wool would have the same effect as fine emery

Offline florence

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Re: Polishing rusty chrome
« Reply #2 on: November 13, 2025, 12:19:30 PM »
I use those green pan scourers and brasso but then I am a hooligan.

Offline Rayzerman

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Re: Polishing rusty chrome
« Reply #3 on: November 13, 2025, 03:10:03 PM »
A bit of experience, I de-rusted my CB350F rear fender and it came out very well.  I was not pitted.  There are various methods, see a couple of sample videos below... the key is you will need an acidic cleaner to start, and since one can't immerse a whole fender, I brushed on a liquid rust remover.  I later found a gel type, either will work.  I used a toothbrush to work it in occasionally, use more remover... it is water soluble, so rinse and repeat as needed.  On a couple stubborn spots, I used 0000 steel wool, I finished up with Autosol, and even tried Novus #2, which is a plastic polish with some very fine abrasive in it.  Both OK, just need elbow grease.

My exterior did not have pitting, so it came out very well.  The old chrome seems to have something I call "checking" not scratches, but just some kind of patina.  I recently have discovered methods of polishing paint to a show mirror finish, so I may attempt that.  But I'm also OK with this patina (you have to look for it), but the paint polish I have is super fine and no harm in trying it.

On the inner fender, the rust was everywhere and some pitting.  I brushed on the liquid rust remover generously, even used a brass brush.  I let soak for a couple of hours, then rinsed it off.  Repeated 3 times, knowing I was never going to get it all off or spend way too much time on it.  Since it's going to rust again, after getting it as good as I could, I masked off the edges and sprayed a "chrome" paint on it.  Knowing that would most likely not be durable enough, I sprayed a rubberized clear Leak Seal.  Tough to get uniform, so use light coats.  It comes out milky with the chrome paint (really not very glossy anyway) barely showing through the thicker rubber coating.  It's hidden, anyone looking would just see a silver appearance, but at least no rust showing.  It is sealed and rubberized, so won't chip or ever rust through again IMHO.

I haven't tried posting pictures here, but will attempt that.

My recommendation, try combination of methods but no abrasives coarser than 0000 steel wool, and some method of lubrication (Coke, water, vinegar, or some kind of gel or oil).  No to Scotchbrite pads, lol. If pitted, well, you will minimize them but not going to get rid of them.  My front fender unfortunately was bent previously, impossible to fix all the dents.... I just bought a new replica front fender..... justify it by paying yourself a small wage multiplied by the hours you'll spend, lol.  I could have bought a rear too, but it was good enough to restore.  And as likely many know, in doing a full restoration, in all likelihood, you're going to spend more than the bike is worth........

https://www.youtube.com/watch?v=YCaernur0g8

https://www.youtube.com/watch?v=vWCIpexgZm0

 
'72 CB350F, 2010 CBF1000FA

Offline kevski

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Re: Polishing rusty chrome
« Reply #4 on: November 13, 2025, 09:02:12 PM »
Polishing chrome surfaces removes small amounts of chrome, the problem is that a lot of these old chrome guards have very little if any nickel or copper under the chrome, chrome has macro cracking naturally so therefore is not waterproof,  the iron in the steel oxidises and creates the problem, use aluminuim foil and wd 40 and rub the rust away, then use a very fine polish like brasso or silvo as these are finer than solvol.
My first post in 2 and1/2 years.

Offline Ken4004

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Re: Polishing rusty chrome
« Reply #5 on: November 13, 2025, 10:44:19 PM »
Hi Kevski

That’s what I have been concerned about removing too much chrome, like the sound of the WD40 and foil, I suppose it easy to get carried away to achieve fast results.

It’s a shame so many chrome companies have closed down because all of the strict regulations, I would like to get an exhaust re chromed but I have heard that they are reluctant to take on exhausts because they don’t want their tanks contaminated with carbon debris.

I am going out to China next month so might see if I can find a place out there it’s got to be cheaper, I have a chain guard I would like to get re chromed.
I have tried to email several chromers but their so busy unless it’s a big job they are not really interested, have been waiting for CMSNL to produce some more after market ones.

Offline K2-K6

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Re: Polishing rusty chrome
« Reply #6 on: November 14, 2025, 07:21:10 AM »
My understanding of it has been the visible rust is from base material corrosion (as noted in previous posting) passing through the chrome (ostensibly immune to corrosion) in appearing on the top layer.

Something very gentle, if you have a circular random orbit sander, for DIY perhaps ? A dense wool pad fitted to that, then use a caravan or acrylic bath cleaner paste (both in super fine abrasive, effectively) then keeping the pad dampened with a little water while you polish is very effective. 

A suggestion, given that it's corrosion coming through the chrome, and if its substantially poor anyway  ....  use of a rust "converter could arrest that corrosion prior to stating a polish routine. Perhaps a longer lasting stay of execution from chemical conversion would be successful.

Offline royhall

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Re: Polishing rusty chrome
« Reply #7 on: November 15, 2025, 06:34:33 PM »
Whatever you try the rust will eventually return. It's due to a poor chroming job that skipped the copper plating part. Nickel and chromium are slightly porous so without the copper the base layer of steel will always rust through. Pay cheap gets a cheap job.

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Offline K2-K6

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Re: Polishing rusty chrome
« Reply #8 on: November 15, 2025, 09:41:44 PM »
I was considering it more in context of trying to at least best halt or save an original part from further deterioration, at least to conserve what exists at that point.

I did think that was the focus of original post and question though.

Offline Ken4004

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Re: Polishing rusty chrome
« Reply #9 on: November 19, 2025, 06:29:25 PM »
Whatever you try the rust will eventually return. It's due to a poor chroming job that skipped the copper plating part. Nickel and chromium are slightly porous so without the copper the base layer of steel will always rust through. Pay cheap gets a cheap job.

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So are you saying that the original chrome from Honda was a bit hit and miss when it came to the  plating  process or as you say they took a short cut and missed the copper plating base layer ?

Or maybe they used the plating chemicals for too long and some of the chrome parts had a sub standard finish when  the chemicals past their best !