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Posted by edramshaw@gmail.com on April 29, 2008, 11:58 am
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Ok, so I am an idiot. I pushed things too far and may have cost myself
a bit of money in the process. I work with beer equipment and had some
old brass draft beer towers that needed some love. One of the cleaning
chemicals I work with is hydrochloric acid and I've noticed that when
I use this on brass parts they shine. I think this may work on the
tower I have so I soak it in a solution of 7 oz. hydrochloric acid and
4 gallons of water overnight. First day it looks good, second day it
looks better, third even better, fourth day it is pink! What happened?
Is there anything I can do to restore the shine? Any help would be
appreciated because I would like to save this thing if I can. Thanks
in advance.
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Posted by Ed Huntress on April 29, 2008, 12:18 pm
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> Ok, so I am an idiot. I pushed things too far and may have cost myself
> a bit of money in the process. I work with beer equipment and had some
> old brass draft beer towers that needed some love. One of the cleaning
> chemicals I work with is hydrochloric acid and I've noticed that when
> I use this on brass parts they shine. I think this may work on the
> tower I have so I soak it in a solution of 7 oz. hydrochloric acid and
> 4 gallons of water overnight. First day it looks good, second day it
> looks better, third even better, fourth day it is pink! What happened?
> Is there anything I can do to restore the shine? Any help would be
> appreciated because I would like to save this thing if I can. Thanks
> in advance.
If it's pink, you've de-zincified it. Hope that it's only on the surface. If
so, you may be able to abrade the surface copper off (maybe some fine
wet-dry sandpaper, followed by a couple of grades of abrasive polish) and
get back down to brass.
Or maybe you'll get really lucky and someone here will have an easier
solution. Good luck.
--
Ed Huntress
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Posted by Paul K. Dickman on April 29, 2008, 1:26 pm
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>
>> Ok, so I am an idiot. I pushed things too far and may have cost myself
>> a bit of money in the process. I work with beer equipment and had some
>> old brass draft beer towers that needed some love. One of the cleaning
>> chemicals I work with is hydrochloric acid and I've noticed that when
>> I use this on brass parts they shine. I think this may work on the
>> tower I have so I soak it in a solution of 7 oz. hydrochloric acid and
>> 4 gallons of water overnight. First day it looks good, second day it
>> looks better, third even better, fourth day it is pink! What happened?
>> Is there anything I can do to restore the shine? Any help would be
>> appreciated because I would like to save this thing if I can. Thanks
>> in advance.
>
> If it's pink, you've de-zincified it. Hope that it's only on the surface.
> If so, you may be able to abrade the surface copper off (maybe some fine
> wet-dry sandpaper, followed by a couple of grades of abrasive polish) and
> get back down to brass.
>
> Or maybe you'll get really lucky and someone here will have an easier
> solution. Good luck.
>
> --
> Ed Huntress
>
Ed's right , you have etched the zinc out of the surface.
If you are lucky and it is not too deep, you can use a hydrogen peroxide
pickle technique to strip back the copper rich surface.
http://www.artmetal.com/files/imported/project/TOC/finishes/nonfe/H2O2.html
It will leave the surface dull, but well within the range of hand polishing.
4 gal is a lot of peroxide though.
It is also a great technique for cleaning up when you burn out the zinc with
a torch after silver brazing or etching it out with acid flux.
HCl is a little strong for general cleaning. I prefer citric acid or sodium
bisulfate (AKA Sparex, or sold in the pool supply section under various
brand names as a granular ph reducer for pool water).
Paul K. Dickman
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Posted by Don Foreman on April 29, 2008, 4:49 pm
Please log in for more thread options On Tue, 29 Apr 2008 12:26:41 -0500, "Paul K. Dickman"
>
>
>
>http://www.artmetal.com/files/imported/project/TOC/finishes/nonfe/H2O2.html
>
>It will leave the surface dull, but well within the range of hand polishing.
>4 gal is a lot of peroxide though.
>
>It is also a great technique for cleaning up when you burn out the zinc with
>a torch after silver brazing or etching it out with acid flux.
Way cool, Paul!
H202 is available at Wal-Mart (pharmacy) for about a buck a quart
IIRC.
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Posted by Paul K. Dickman on April 29, 2008, 5:36 pm
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> On Tue, 29 Apr 2008 12:26:41 -0500, "Paul K. Dickman"
>
>>
>>
>>
>>http://www.artmetal.com/files/imported/project/TOC/finishes/nonfe/H2O2.html
>>
>>It will leave the surface dull, but well within the range of hand
>>polishing.
>>4 gal is a lot of peroxide though.
>>
>>It is also a great technique for cleaning up when you burn out the zinc
>>with
>>a torch after silver brazing or etching it out with acid flux.
>
> Way cool, Paul!
>
> H202 is available at Wal-Mart (pharmacy) for about a buck a quart
> IIRC.
It works pretty good. I has to be hot though. When working with small stuff
I heat up a cupful in the microwave.
Clean off the flux and pickle off the black scale as usual, then use this to
blast off the copper.
The vinegar solution is pretty aggressive. It is worth tracking down the
sodium bisulfate, but use it all the time for jewelry work so I always have
it on hand.
Only mix up as much of the peroxide mix as you will use right away. It'll
process a fair bit of metal but the peroxide starts breaking down the second
you open the bottle and your mix will be mostly water if you try to use it
the next day.
Paul K. Dickman
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> a bit of money in the process. I work with beer equipment and had some
> old brass draft beer towers that needed some love. One of the cleaning
> chemicals I work with is hydrochloric acid and I've noticed that when
> I use this on brass parts they shine. I think this may work on the
> tower I have so I soak it in a solution of 7 oz. hydrochloric acid and
> 4 gallons of water overnight. First day it looks good, second day it
> looks better, third even better, fourth day it is pink! What happened?
> Is there anything I can do to restore the shine? Any help would be
> appreciated because I would like to save this thing if I can. Thanks
> in advance.