# Instruments and Equipment > Builders and Repair >  Oxidizing Chrome parts

## Dido

Any suggestions on oxidizing some chrome parts both quickly and cheaply?

Thanks.

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## Spruce

What are you trying to do?  Make it look old and pitted, or just dulling it down a little?
You could try putting the parts in a sealed tupperware container with a shot glass full of vinegar...

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## multidon

http://www.stewmac.com/tsarchive/ts0017.html

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## Spruce

> http://www.stewmac.com/tsarchive/ts0017.html


That method works with nickel parts, but the chrome will just laugh at it...
I'm doing some chrome as we speak with the vinegar method, and it's pitting pretty nicely after a week or so...
I can post some pics if you want...

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## multidon

Hey Spruce!

I may be wrong about this, but I believe I heard somewhere that most chrome instrument hardware actually has a layer of nickel underneath it so i was thinking a good aggressive scuff sanding might allow the etchant to penetrate to the nickel layer?

If vinegar works on chrome maybe a more powerful acid would make the work go faster? Maybe photographic grade acetic acid (also known as "stop bath", a 20 percent solution as opposed to 5 percent for vinegar)? Or maybe something like muriatic acid?

I thought the parts of the newsletter about scuff sanding, discoloring, and adding age spots was all good.

Addendum: Quick internet search reveals that muriatic acid (dilute form of hydrochloric acid available at hardware stores for cleaning concrete) will indeed etch chromium within a few minutes. In fact the reaction is so vigorous it can remove chrome plating if you aren't careful. This is tricky stuff to use however Must be used in well ventilated area with acid proof gloves and eye protection etc. Interestingly it will not affect nickel. So Spruce's method with the vinegar takes much longer but is much safer. So I guess it comes down to quick and dangerous vs. slow and safe.

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## Michael Weaver

All chrome plating has an electroplated layer of nickel under it. Unless it is hard chromed which is never the case unless it's going inside a machine or engine.

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## Spruce

> What are you trying to do?


We're still waiting for an answer on this...

When I do antiquing on a guitar or mandolin, I usually leave the chrome stuff (neck plates, certain knobs, Tele control plates) pretty much unscathed--just as you see them on most of the old vintage instruments...



Nickel however, is fair game...

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## Gail Hester

Spruce has more experience than I do at the relic guitar thing but here's a "62" looking Strat that I did recently using circuit board etchant from Radio Shack on the hardware.  The chrome parts are easier that just nickel plated (like the tuners).  You can completely remove the nickel too quickly so be careful.  There are some Youtube's on the subject that are helpful.

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## Dido

Sorry guys been away all afternoon.  I am just trying to age the metal quickly.  Make it look vintage quick.  I just wet sanded my km 150 this morning with 600 and am going to apply 1500 wet sand this evening.  The metal just looks to shinny.

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## Mickey King



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## Spruce

Nice!!

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## kjbllc

under the nickel there will probably be copper plating

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## Dido

Spruce, Do I put the parts directly in the white vinegar or like the muriatic acid video, tupperware inside of tupperware?  How long do I keep the parts in there, can I leave them in there all day?  Its another hectic day today!

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## Zissou Intern

Hey Dido,
Can you post some pictures of the sanding when you are finished? 
Thanks,
Z

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## Dido

Absolutely, I have 2 threads going on this subject...I was initially going to use steel wool.  Luckily, I was informed not to!

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## Spruce

> Spruce, Do I put the parts directly in the white vinegar or like the muriatic acid video, tupperware inside of tupperware?


Just put a shotglass (or rattlecan lid) full of vinegar in the sealed container...
It'll pit and green the parts--a lot like nature does in the wild...    :Wink: 




> How long do I keep the parts in there, can I leave them in there all day?


Here's a pic taken after a week or so of fuming...
I'll wash the greening off, but the dulled pitting will remain, along with some of the greening...

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## Dido

I started a new thread with pics...Thanks for all the help.

http://www.mandolincafe.com/forum/sh...tressed-Km-150

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