Author Topic: Removing Chrome from aluminum parts  (Read 3470 times)

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Offline Dusthawk

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Removing Chrome from aluminum parts
« on: December 23, 2007, 05:52:08 AM »
Any ideas on how to get this flaking mess of chrome off?
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Offline smack doogle

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Re: Removing Chrome from aluminum parts
« Reply #1 on: December 23, 2007, 06:43:14 AM »
Mine looks the same way and I would like to know also.  I was just going to sand it down but maybe there is a better route?
What's my problem?  I'm from Wisconsin, that's what my problem is.



tbone

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Re: Removing Chrome from aluminum parts
« Reply #2 on: December 23, 2007, 07:52:04 AM »
The big problem with sanding it off is that the chrome is much harder than the aluminum.

The best route is to find a local plater in your area. Many of them have a tank set up for stripping old chrome off parts to be re-plated.



Offline bryanj

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Re: Removing Chrome from aluminum parts
« Reply #3 on: December 23, 2007, 08:00:19 AM »
The reason platers hate alluminium is that when you plate it it wrecks the chemicals so they only tend to do it when they need changing anyway
And removing it is more of a pain that plating it
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Offline kirkn

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Re: Removing Chrome from aluminum parts
« Reply #4 on: December 23, 2007, 08:04:10 AM »
Hmmm.....  is that CHROME?

I always thought that OEM coating on the various aluminum parts was some kind of paint / clear coat combo?

I've heard that a product, available at WalMart, call Aircraft Stripper, will take that OEM coating off, leaving the aluminum ready for sanding/prep/polish/paint/whatever.

I picked up an aerosol can of the stuff yesterday, coincidentally, and tested it on some old Honda XL parts on one of my project bikes.  Seems to do the job!  This one didn't have much of the OEM finish left, and had been repainted by someone, but this stuff did a good job!  I'll also be doing the engine case covers for that project, and that will be a better test.

Spray it on, it bubbles and thickens, let it sit for half an hour, then rinse & scrub with an old sponge.

Good luck with yours.

Kirk



Offline Bob Wessner

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Re: Removing Chrome from aluminum parts
« Reply #5 on: December 23, 2007, 08:11:27 AM »
I'm guessing it is chrome, done after the fact by the PO likely. I have a spare engine with some chrome plated alum. parts and I'd like to find some way to strip them also.
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Offline Tim.

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Re: Removing Chrome from aluminum parts
« Reply #6 on: December 23, 2007, 08:18:34 AM »
Not to derail the discussion on how to remove chrome (which I'm interested in as well), but if this is the only peice you need to have done, it's a small and common enough piece that I'd suggest just replacing it.

Surely someone here has a spare they'd offer up.  I'd mail you one but I just recently got rid of all my old 750 stuff.
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Offline eurban

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Re: Removing Chrome from aluminum parts
« Reply #7 on: December 23, 2007, 09:32:21 AM »
Yes replacement might be a wise option.  Seems pretty common now on Ebay to see just about all of the various engine covers to be offered up in supposedly nice fully polished shape.  Prices vary but if you have ever made the attempt to do a full out polish job on some of these parts, the prices don't seem too outrageous.



Offline Bodain

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Re: Removing Chrome from aluminum parts
« Reply #8 on: December 23, 2007, 01:16:40 PM »
If you've ever used Muratic acid to get rid of rust. You know it will eat chrome almost immediately.
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Offline Patrick

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Re: Removing Chrome from aluminum parts
« Reply #9 on: December 23, 2007, 01:29:01 PM »
It'll eat aluminum very quickly, too.
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Offline roach carver

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Re: Removing Chrome from aluminum parts
« Reply #10 on: December 23, 2007, 02:12:43 PM »
i would think that you could un-plate it in a manner similar to plating but reverse the positive and negative ?



Offline Dusthawk

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Re: Removing Chrome from aluminum parts
« Reply #11 on: December 23, 2007, 02:27:41 PM »
Not to derail the discussion on how to remove chrome (which I'm interested in as well), but if this is the only peice you need to have done, it's a small and common enough piece that I'd suggest just replacing it.

Surely someone here has a spare they'd offer up.  I'd mail you one but I just recently got rid of all my old 750 stuff.

Yes, well, there you found the rub in that idea, I only posted picks of the breather to save space but to give an idea of what I want to do. Most of the covers on Rita have been chromed like this, Stator cover, Trans cover, Valve cover etc. That is a lot of parts to replace. I already have a new valve cover and breather cover to replace these chromed ones but would like to see if I can remove the chrome so I can polish them before returning them to Scondon, who provided the replacements. I have a bench grinder and polishing wheels on the way, and plenty of time to polish, so I thought it the least I could do for Scondon.

Plus, since I will soon be tearing the engine down for the rebuild of the top end, it is a good time to figure out how to remove the chrome and polish up these other parts as well.

Oh, Kirkn, it is for sure chrome, I used a brass brush to remove a lot of the flaky crap and it isn't the clearcoats a lot of people use, but thanks for the thought.

"Unplating" won't work either as the chrome is already bonded to the aluminum.
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Offline Tim.

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Re: Removing Chrome from aluminum parts
« Reply #12 on: December 23, 2007, 04:12:46 PM »
I'd go to the experts.  Know a local plater?
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Caferacingparts

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Re: Removing Chrome from aluminum parts
« Reply #13 on: December 23, 2007, 04:49:52 PM »
The reason platers hate alluminium is that when you plate it it wrecks the chemicals so they only tend to do it when they need changing anyway
And removing it is more of a pain that plating it
   I think you are thinking of carbon. Most platers won't touch used mufflers or pipes for this reason. Any carbon in the solution will cause problems with any future chrome jobs.  Of the 3 chrome shops I have used, none have had a problem with removing old chrome from aluminum parts. And each has told me that the reverse procedure they use is the only way to remove the chrome without destroying the aluminum.
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Offline 754

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Re: Removing Chrome from aluminum parts
« Reply #14 on: December 23, 2007, 04:57:05 PM »
after a few decades of being around bikes,


I have only heard that reversing will remove the chrome.. BUT NOT THE NICKEL.. which is fairly hard..

Usually you are faced with sanding/polishing it off.. buy another set and save these for powdercoat.. or the valve cover for a smoothed look..
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tbone

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Re: Removing Chrome from aluminum parts
« Reply #15 on: December 23, 2007, 08:38:21 PM »
Nickel requires a different solution so you are right that the reversed chrome solution won't remove it but a reversed nickel solution will.

Also, Caswell Plating sells an electroless nickel stripper.

http://www.caswellplating.com/kits/metalx.html



Offline bathcollector

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Re: Removing Chrome from aluminum parts
« Reply #16 on: December 23, 2007, 11:53:38 PM »
Platers can remove the chrome for you, i had a set of Donovan Hemi valve covers done. They come out quite dark in appearance but rebuff nicely



Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Removing Chrome from aluminum parts
« Reply #17 on: December 24, 2007, 12:40:49 AM »
My vote is to rechrome them or pitch them and replace them. I would think it would be cheaper to have replacements chromed than to attempt to rechrome those and have them come out badly. 
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Offline Dusthawk

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Re: Removing Chrome from aluminum parts
« Reply #18 on: December 24, 2007, 03:23:04 AM »
My vote is to rechrome them or pitch them and replace them. I would think it would be cheaper to have replacements chromed than to attempt to rechrome those and have them come out badly. 

That is all well and good for the breather cover, but what about the valve cover, stator, clutch covers, all the chromed aluminum pieces are chromed and pitted and corroded. The nearest Chromer is a couple hours away by car, I will find an Email to contact them to find out what they think they can do.
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Offline eurban

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Re: Removing Chrome from aluminum parts
« Reply #19 on: December 24, 2007, 08:46:48 AM »
Not that I love ebay or anything but . . .Just did a search on ebaymotors for "cb750 polished"  . There are a good number of pieces listed most of which are offered at buy it now.  Looks like at this very moment you could buy all the covers (didn't see the breather) in a polished state for between $200 and $300.  Search for non polished stuff under "cb750 cover" . . .Put a request on this site for a complete cover set and see what happens?  Abrasive blast your covers and have them chrome like powdercoated? Seems like any of these options would be easier than finding a plater to dechrome unless you have a good connection in the industry.  Even after the process you will still need to do a bit of work to get the parts looking close to stock or a lot of work to get them polished or rechromed. . . .
« Last Edit: December 24, 2007, 09:01:58 AM by eurban »



Offline cleveland

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Re: Removing Chrome from aluminum parts
« Reply #20 on: December 24, 2007, 10:40:40 AM »
A local plater (Wisconsin Plating) offered to chem dip 2 tanks and a crap load of smaller parts for $50.  That being the case, I'd rather have them dipped and polish them myself.  I am a cheap skate and look to go the most economical route. 



Offline eurban

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Re: Removing Chrome from aluminum parts
« Reply #21 on: December 24, 2007, 01:45:37 PM »
A local plater (Wisconsin Plating) offered to chem dip 2 tanks and a crap load of smaller parts for $50.  That being the case, I'd rather have them dipped and polish them myself.  I am a cheap skate and look to go the most economical route. 

Chem dip to remove real chrome plate?  Is this an acid dip (if so see the destructive effect of acid on aluminum parts warning earlier in this thread)?  The process for deplating chrome would typically not be called a "chem dip" and might run you a good bit more than $50, but who knows . . . .



Offline 736cc

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Re: Removing Chrome from aluminum parts
« Reply #22 on: December 24, 2007, 02:40:16 PM »
 My plater charged $20 to de-chrome an alternator cover that had really flaky chrome. Came back kinda dark but smooth and fresh,and ez to refinish.
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Re: Removing Chrome from aluminum parts
« Reply #23 on: December 24, 2007, 07:02:19 PM »
Yeah, I've had some aluminum parts "de-plated" and a complete RC drag bike exhaust too, with no problems at all.

There's no "acid bath" technique that I know of that'll remove chrome/nickel/copper plating without dissolving the aluminum, (well, "pot metal" is probably more accurate) these parts of mine were all "reverse plated" to successfully remove the old chrome.

I've also had old chrome sand blasted off, that works quite well too, and can still be polished, but it'll take some work to get the pitting out. In this case Jeff, you might be better off buying good used non-plated parts though, used CB750 covers are cheap, and the removal process can get expensive. Cheers, Terry. ;D
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Offline Patrick

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Re: Removing Chrome from aluminum parts
« Reply #24 on: December 24, 2007, 09:25:29 PM »
A few weeks ago while working on my K0 I was using muriatic acid to derust some steel parts. I accidentally (?) dropped an old carb body into the acid. Wow, like Mentos into Pepsi. The acid immediately boiled up and the carb body sizzled.

It was pretty cool.

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