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How do you remove chrome from brass?

Postby Psyd on Wed Dec 02, 2009 10:30 pm

I know, I know, most folk would be asking how to keep the chrome attached to the brass.
I'd like to find a way to separate the chrome from a plated brass portafilter without resorting to removing it with some sort of abrasive physical activity.

I have some PF's that some of the chrome is flaking off, and I'd like to see what they look like with an all brass finish.

Not enough to go through all of the painstaking grinding, sanding, finishing and polishing, though, of course! ; >
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Postby espressme on Wed Dec 02, 2009 10:41 pm

All I can add is the following thread from here on H-B:
Here and Removing portafilter chrome?
Good luck
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Postby Psyd on Wed Dec 02, 2009 11:23 pm

espressme wrote:All I can add is the following thread from here on H-B:


Yeah, I was in on those from the beginning. That's why I stuck the 'no manual labour' caveat in there in the first place!

Truly, I can't buy any more single use power tools (long story) and I am at the point where I have to start thinking carefully about any repetitive stress activities.

I was hoping that someone would come up with a lemon juice and Ajax soak, or something...
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Postby CRCasey on Wed Dec 02, 2009 11:29 pm

I thought the point of chroming a surface was to put a micro thin layer of oxidation on a metal that would protect the underlying metal. So I would guess that you would need something that would attack that protective layer and then stop when you got to the base layer.

Someone that knows a lot more about metallurgy will have to step in here.

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Postby mike01 on Thu Dec 03, 2009 1:15 am

I've heard before that muriatic acid (hydrochloric acid) will remove chrome. You can usually buy it at Home Depot or Lowes. Make sure to be very careful and follow the precautions on the bottle, that stuff is extremely corrosive.
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Postby malachi on Thu Dec 03, 2009 1:26 am

Most good coffee bars that use spouted portafilters strip the chrome off immediately.
The two most common methods are:
- wire brush attachment followed by green scrubby on a buffing pad on a power drill
- acid

I've used both and vastly prefer the second option (though, of course, you need to be very careful - use the right equipment and safety apparel - do it outside - etc).
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Postby Psyd on Thu Dec 03, 2009 10:15 pm

malachi wrote:I've used both and vastly prefer the second option


Which acid do you recommend, and how do you protect the brass underneath?

OTOH, it may be prudent to go out and buy that dual wheel bench grinder with a wire wheel on one side and a buffing wheel on the other...
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Postby cagiva905 on Fri Dec 04, 2009 3:35 pm

Personally I would bring the parts you need de-chromed to a plating shop that normally does the applying of chrome on metals. They will be able to remove the chrome without any hardware causing scratches etc. If needed they can probably polish the parts as well, as being part of their business.

Addressees can very likely be found in magazines for car / motorbike restoration etc.
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Postby mjgkiwi on Fri Dec 04, 2009 6:31 pm

As someone who used to work in this field, I can confirm Hydrochloric acid (aka muriatic) will indeed remove chrome plating and if the brass has been preplated with copper, it will remove this also. Be warned that Hydrochloric acid WILL attack brass, in fact it is used to etch brass prior to plating so monitor the stripping carefully.
This acid will also remove bits of clothing, skin and concrete floors if due care isn't taken.
The safest option, and it probably won't cost much, is to go to a chrome platers and ask them to strip it. Platers who do restoration work will do this sort of thing all the time.

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Postby Psyd on Fri Dec 04, 2009 8:55 pm

mjgkiwi wrote:The safest option, and it probably won't cost much, is to go to a chrome platers and ask them to strip it. Platers who do restoration work will do this sort of thing all the time.


I've dealt with the local platers for a coupla reasons. they tend to want to charge as much for a one-off small gig as they would a full run. I understand that it doesn't pay to meddle in the small stuff.*
I was afraid that I'd have to resort to HCL or manual labour, but I guess this means that I get to buy the bench grinder now!
Yeah, there is too much brass exposed to want to sink the entire thing into HCL, and too much hassle to paint it. I'll check with a coupla platers, but I'm guessing that I'm gonna have to bear down and do it manually. Thanks for the advice!



*I did, at one point, have our annual engineering award (a gold plated 'tweaker' or small screw-driver for making electronics adjustments) plated fairly inexpensively by dropping it off with one understanding plater who would throw it in with the next batch of gold plating with the understanding that it would get done when it got done.
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