26 Nov
2001
26 Nov
'01
2:04 p.m.
I've never used citric acid, but for nitric you wash it with the nitric
and let it air dry (ie, do not rinse).
By the way, the reason you need to passivate stainless is so it remains
stainless--without the protective coat it will stain and corrode
On Mon, 26 Nov 2001 10:27:49 -0800 (PST) Will Holway <brew987(a)yahoo.com>
writes:
I actually have some citric acid in powdered form.
what is the method? Just let it soak overnight or
something? Do I need to first try to clean the
stainless steel as best I can then let it soak?
Thanks,
WH
--- "Crist, Jonathan" <cristj(a)bsci.com> wrote:
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I agree with Dave - you typically need the nitric
acid
You probably can't find it as a homebrewer but Acid
#5 from Five Star
Chemicals works very well. It is a blend of nitric
acid, phosphoric acid and
other acids to help clean and passivate the surface.
Another method to passivate stainless steel is with
citric acid. This is
safer and sometimes faster than nitric acid.
Solutions with 4 to 10% citric
acid (by weight) will safely remove the iron oxide
and free iron and leave a
chrome oxide rich (passivated) surface.
Jonathan Crist
________________________________________________________________
----------
From: David H Berg[SMTP:bergbrew@juno.com]
Sent: Monday, November 26, 2001 10:59 AM
To: brew987(a)yahoo.com
Cc: mba(a)thebarn.com
Subject: Re: Re-Passifying Stainless Steel
Your need to use Nitric acid to pacify
stainless--phosphoric won't cut
it.
On Mon, 26 Nov 2001 08:30:30 -0800 (PST) Will
Holway <brew987(a)yahoo.com>
writes:
> Hi,
>
> I think I saw some postings on this subject
before. It
> has recently come to my attention that my
method
for
> cleaning up my 1/2 barrell kegs (using the
3M
green
> scrubby pads) actually takes off some of the
SS
> protective coating. I am curious if I can
re-passify
> teh SS by using phosphoric acid. Does anyone
know the
> "recipe" for doing this? I have
not noticed any
off
> flavors, or oxidation as of yet, but was
curious
of
> others' opinions of this etc., and if
it is a
> reasonable course of action to pursue ...
>
> Thanks,
> WH
> WindRiver Brewing
>
>
__________________________________________________
> Do You Yahoo!?
> Yahoo! GeoCities - quick and easy web site
hosting, just
$8.95/month.
http://geocities.yahoo.com/ps/info1
GET
INTERNET ACCESS FROM JUNO!
Juno offers FREE or PREMIUM Internet access for
less!
> Join Juno today! For your FREE software, visit:
> http://dl.www.juno.com/get/web/.
> 
26 Nov
26 Nov
2:13 p.m.
New subject: Re-Passifying Stainless Steel
Here is a message from the HBD May 15, 2000 from John Palmer who is a
metallurgist. I think we may be going overboard in Will's kegs here.
Since I don't brew daily I can just get by with letting atmospheric
oxygen do the job for me when I need to scrub the kettle.
+ Date: Mon, 15 May 2000 08:33:14 -0700
+ From: "John Palmer" <jjpalmer(a)gte.net>
+ Subject: Stainless passivation
+
+ Passivating Stainless Steel
+ A situation that often comes up is, "Hey, my stainless steel is
+ rusting! Why? What can I do to fix it?"
+
+ Stainless steel is stainless because of the protective chromium oxides
+ on the surface. If those oxides are removed by scouring, or by
+ reaction with bleach, then the iron in the steel is exposed and can be
+ rusted. Stainless steel is also vulnerable to contamination by plain
+ carbon steel, the kind found in tools, food cans, and steel wool. This
+ non-stainless steel tends to rub off on the surface (due to
+ iron-to-iron affinity), and readily rusts. Once rust has breached the
+ chromium oxides, the iron in the stainless steel can also rust. Fixing
+ this condition calls for re-passivation.
+
+ Passivating stainless steel is normally accomplished in industry by
+ dipping the part in a bath of nitric acid. Nitric acid dissolves any
+ free iron or other contaminants from the surface, which cleans the
+ metal, and it re-oxidizes the chromium; all in about 20 minutes. But
+ you don't need a nitric acid bath to passivate. The key is to clean
+ the stainless steel to bare metal. Once the metal is clean (and dry),
+ the oxygen in the atmosphere will form the protective chromium oxides.
+ The steel will be every bit as passivated as that which was dipped in
+ acid. The only catch is that it takes longer-- about a week or two.
+
+ To passivate stainless steel at home without using a nitric acid bath,
+ you need to clean the surface of all dirt, oils and oxides. The best
+ way to do this is to use an oxalic acid based cleanser like Bar
+ Keepers Friend, RevereWare Cleanser, or Kleen King, and a non-metallic
+ green scrubby pad. Don't use steel wool, or any metal pad, even
+ stainless steel, because this will actually promote rust. Scour the
+ surface thoroughly and then rinse and dry it with a towel. Leave it
+ alone for a week or two and it will re-passivate itself. You should
+ not have to do this procedure more than once, but it can be repeated
+ as often as necessary.
+
+ John Palmer
+ www.realbeer.com/jjpalmer/
David H Berg writes:
I've never used citric acid, but for nitric you wash it with the nitric
and let it air dry (ie, do not rinse).
By the way, the reason you need to passivate stainless is so it remains
stainless--without the protective coat it will stain and corrode
On Mon, 26 Nov 2001 10:27:49 -0800 (PST) Will Holway <brew987(a)yahoo.com>
writes:
> I actually have some citric acid in powdered form.
> what is the method? Just let it soak overnight or
> something? Do I need to first try to clean the
> stainless steel as best I can then let it soak?
>
> Thanks,
> WH
--
Steve Piatz piatz(a)cray.com
Cray Inc. 651-605-9049
1340 Mendota Heights Road
Mendota Heights, MN 55120
3:41 p.m.
New subject: Re-Passifying Stainless Steel
So,
Since I thought that the green scrubby pads were the
potential source of the problem, scrubbing them with
the green scrubby pad and then letting them sit
exposed to the air for several weeks before the next
brew re-passivates the staineless steel?
Cheers!
WH
--- Steve Piatz <piatz(a)cray.com> wrote:
Here is a message from the HBD May 15, 2000 from
John Palmer who is a
metallurgist. I think we may be going overboard in
Will's kegs here.
Since I don't brew daily I can just get by with
letting atmospheric
oxygen do the job for me when I need to scrub the
kettle.
+ Date: Mon, 15 May 2000 08:33:14 -0700
+ From: "John Palmer" <jjpalmer(a)gte.net>
+ Subject: Stainless passivation
+
+ Passivating Stainless Steel
+ A situation that often comes up is, "Hey, my
stainless steel is
+ rusting! Why? What can I do to fix it?"
+
+ Stainless steel is stainless because of the
protective chromium oxides
+ on the surface. If those oxides are removed by
scouring, or by
+ reaction with bleach, then the iron in the steel
is exposed and can be
+ rusted. Stainless steel is also vulnerable to
contamination by plain
+ carbon steel, the kind found in tools, food cans,
and steel wool. This
+ non-stainless steel tends to rub off on the
surface (due to
+ iron-to-iron affinity), and readily rusts. Once
rust has breached the
+ chromium oxides, the iron in the stainless steel
can also rust. Fixing
+ this condition calls for re-passivation.
+
+ Passivating stainless steel is normally
accomplished in industry by
+ dipping the part in a bath of nitric acid. Nitric
acid dissolves any
+ free iron or other contaminants from the surface,
which cleans the
+ metal, and it re-oxidizes the chromium; all in
about 20 minutes. But
+ you don't need a nitric acid bath to passivate.
The key is to clean
+ the stainless steel to bare metal. Once the metal
is clean (and dry),
+ the oxygen in the atmosphere will form the
protective chromium oxides.
+ The steel will be every bit as passivated as that
which was dipped in
+ acid. The only catch is that it takes longer--
about a week or two.
+
+ To passivate stainless steel at home without using
a nitric acid bath,
+ you need to clean the surface of all dirt, oils
and oxides. The best
+ way to do this is to use an oxalic acid based
cleanser like Bar
+ Keepers Friend, RevereWare Cleanser, or Kleen
King, and a non-metallic
+ green scrubby pad. Don't use steel wool, or any
metal pad, even
+ stainless steel, because this will actually
promote rust. Scour the
+ surface thoroughly and then rinse and dry it with
a towel. Leave it
+ alone for a week or two and it will re-passivate
itself. You should
+ not have to do this procedure more than once, but
it can be repeated
+ as often as necessary.
+
+ John Palmer
+ www.realbeer.com/jjpalmer/
David H Berg writes:
__________________________________________________
Do You Yahoo!?
Yahoo! GeoCities - quick and easy web site hosting, just $8.95/month.
http://geocities.yahoo.com/ps/info1
I've never used citric acid, but for nitric you
wash it with the nitric
and let it air dry (ie, do not rinse).
By the way, the reason you need to passivate
stainless is so it remains
stainless--without the protective coat it will
stain and corrode
On Mon, 26 Nov 2001 10:27:49 -0800 (PST) Will
Holway <brew987(a)yahoo.com>
writes:
> I actually have some citric acid in powdered
form.
> what is the method? Just let it soak
overnight
or
> something? Do I need to first try to clean
the
> stainless steel as best I can then let it soak?
>
> Thanks,
> WH
--
Steve Piatz
piatz(a)cray.com
Cray Inc. 651-605-9049
1340 Mendota Heights Road
Mendota Heights, MN 55120
7 p.m.
New subject: Re-Passifying Stainless Steel
It's like Deja vu all over again!
--- Steve Piatz <piatz(a)cray.com> wrote:
Here is a message from the HBD May 15, 2000 from
John Palmer who is a
metallurgist. I think we may be going overboard in
Will's kegs here.
Since I don't brew daily I can just get by with
letting atmospheric
oxygen do the job for me when I need to scrub the
kettle.
+ Date: Mon, 15 May 2000 08:33:14 -0700
+ From: "John Palmer" <jjpalmer(a)gte.net>
+ Subject: Stainless passivation
+
+ Passivating Stainless Steel
+ A situation that often comes up is, "Hey, my
stainless steel is
+ rusting! Why? What can I do to fix it?"
+
+ Stainless steel is stainless because of the
protective chromium oxides
+ on the surface. If those oxides are removed by
scouring, or by
+ reaction with bleach, then the iron in the steel
is exposed and can be
+ rusted. Stainless steel is also vulnerable to
contamination by plain
+ carbon steel, the kind found in tools, food cans,
and steel wool. This
+ non-stainless steel tends to rub off on the
surface (due to
+ iron-to-iron affinity), and readily rusts. Once
rust has breached the
+ chromium oxides, the iron in the stainless steel
can also rust. Fixing
+ this condition calls for re-passivation.
+
+ Passivating stainless steel is normally
accomplished in industry by
+ dipping the part in a bath of nitric acid. Nitric
acid dissolves any
+ free iron or other contaminants from the surface,
which cleans the
+ metal, and it re-oxidizes the chromium; all in
about 20 minutes. But
+ you don't need a nitric acid bath to passivate.
The key is to clean
+ the stainless steel to bare metal. Once the metal
is clean (and dry),
+ the oxygen in the atmosphere will form the
protective chromium oxides.
+ The steel will be every bit as passivated as that
which was dipped in
+ acid. The only catch is that it takes longer--
about a week or two.
+
+ To passivate stainless steel at home without using
a nitric acid bath,
+ you need to clean the surface of all dirt, oils
and oxides. The best
+ way to do this is to use an oxalic acid based
cleanser like Bar
+ Keepers Friend, RevereWare Cleanser, or Kleen
King, and a non-metallic
+ green scrubby pad. Don't use steel wool, or any
metal pad, even
+ stainless steel, because this will actually
promote rust. Scour the
+ surface thoroughly and then rinse and dry it with
a towel. Leave it
+ alone for a week or two and it will re-passivate
itself. You should
+ not have to do this procedure more than once, but
it can be repeated
+ as often as necessary.
+
+ John Palmer
+ www.realbeer.com/jjpalmer/
David H Berg writes:
__________________________________________________
Do You Yahoo!?
Yahoo! GeoCities - quick and easy web site hosting, just $8.95/month.
http://geocities.yahoo.com/ps/info1
I've never used citric acid, but for nitric you
wash it with the nitric
and let it air dry (ie, do not rinse).
By the way, the reason you need to passivate
stainless is so it remains
stainless--without the protective coat it will
stain and corrode
On Mon, 26 Nov 2001 10:27:49 -0800 (PST) Will
Holway <brew987(a)yahoo.com>
writes:
> I actually have some citric acid in powdered
form.
> what is the method? Just let it soak
overnight
or
> something? Do I need to first try to clean
the
> stainless steel as best I can then let it soak?
>
> Thanks,
> WH
--
Steve Piatz
piatz(a)cray.com
Cray Inc. 651-605-9049
1340 Mendota Heights Road
Mendota Heights, MN 55120
8776
days inactive
8776
days old
3 comments
3 participants
participants (3)
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David H Berg -
Steve Piatz -
Will Holway