Nicad leakage

[David Lesher]

When NiCads leak, what's the best substance to neutralize the spill?

[not NiMh; NiCad...]
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[Jon Elson]

David Lesher wrote:

When NiCads leak, what's the best substance to neutralize the spill?

[not NiMh; NiCad...]
Maybe vinegar? The electrolyte is lye (either KOH or NaOH) so a mild

acid should neutralize it. But, it is darn corrosive stuff, so
it will eat many materials pretty quickly.

Jon

 

[Jeff Liebermann]

On Mon, 08 Oct 2012 16:13:38 -0500, Jon Elson <jmelson@wustl.edu>
wrote:

David Lesher wrote:

When NiCads leak, what's the best substance to neutralize the spill?

[not NiMh; NiCad...]

Maybe vinegar? The electrolyte is lye (either KOH or NaOH) so a mild
acid should neutralize it. But, it is darn corrosive stuff, so
it will eat many materials pretty quickly.
Jon

The KOH electrolyte is at about 30% concentration for a pH of about
12. Strong stuff, but not really dangerous. Any acid will wash off
the KOH but may leave salts behind. (That's what's left when the KOH
attacks aluminum, tin, brass, bronze, lead, zinc, etc).

For KOH cleanup, the MSDS sheet recommends dilute acetic acid
(vinegar).
<http://www.westernu.edu/bin/safety/msds/urc/potasium%20hydroxide.pdf>
For cleaning up the salts, I use baking soda, 409 cleaner, or whatever
household cleaner I have handy that evaporates and doesn't leave a
mess.

Note that cadmium is a hazardous waste. Dead NiCd batteries should be
properly disposed of, not mixed with the household trash.

More:
<http://cleaning.lovetoknow.com/How_to_Clean_Leaking_AA_Batteries>

Incidentally, the KOH does not enter into the chemical reactions
inside the battery and just acts as a conduit for the ion exchange.
The KOH concentration is the same for a brand new charged NiCd
battery, as it is for an old dead battery.


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Skype: JeffLiebermann AE6KS 831-336-2558

 

[John Robertson]

David Lesher wrote:

When NiCads leak, what's the best substance to neutralize the spill?

[not NiMh; NiCad...]

http://www.flippers.com/battery.html

John :-#)#

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[Phil Allison]

"David Lesher"

When NiCads leak, what's the best substance to neutralize the spill?

** Not the way to do it at all.

The spill needs to be simply removed - so use tissue and/or clean rags to
get up the worst of it, then use the same dipped in methylated spirits to
get the surfaces clean as possible. Slight surface corrosion can be treated
with WD40.

Any spillage that has become trapped in crevices or small holes must be
washed out ( use a toothbrush ) and the item dried with hot air.

Pouring acid onto alkali inside some piece of equipment is BARKING MAD !!



..... Phil

 

[John Robertson]

Phil Allison wrote:

"David Lesher"
When NiCads leak, what's the best substance to neutralize the spill?

** Not the way to do it at all.

The spill needs to be simply removed - so use tissue and/or clean rags to
get up the worst of it, then use the same dipped in methylated spirits to
get the surfaces clean as possible. Slight surface corrosion can be treated
with WD40.

Any spillage that has become trapped in crevices or small holes must be
washed out ( use a toothbrush ) and the item dried with hot air.

Pouring acid onto alkali inside some piece of equipment is BARKING MAD !!



..... Phil

Well, actually, using a mild acid to neutralize the mild alkali that
leaked is the only way to be sure you have removed the corrosion risk.

Simply washing with pure water isn't quite enough - a 50/50 solution of
water and white vinegar will often bubble even after you have washed the
area. So, scrub some of the 50/50 mixture into the leakage area, then
wash with lots of water.

Look for possible alkali leakage under conformal coatings over the PCB
copper traces as they can be a bit of a time bomb if not the coating is
not scrapped back a bit, then neutralized as well.

Lift/remove connectors - you'd be surprised how little alkali it takes
to eat under these!

Once finished protect with a spray conformal coating.

Not sure how many ni-cad leakage logic boards you have dealt with, but
I'd repaired hundreds.

John :-#)#
--
(Please post followups or tech enquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

 

[gregz]

"Phil Allison" <phil_a@tpg.com.au> wrote:

"David Lesher"

When NiCads leak, what's the best substance to neutralize the spill?

** Not the way to do it at all.

The spill needs to be simply removed - so use tissue and/or clean rags to
get up the worst of it, then use the same dipped in methylated spirits to
get the surfaces clean as possible. Slight surface corrosion can be treated
with WD40.

Any spillage that has become trapped in crevices or small holes must be
washed out ( use a toothbrush ) and the item dried with hot air.

Pouring acid onto alkali inside some piece of equipment is BARKING MAD !!



.... Phil

Ok. I had to look up methylated spirits. Sometimes I just use tap water,
but on good stuff I then use those methylated stuff. Then wd-40 or crc
2-26.
Hot air sometimes.

http://blekko.com/ws/methylated+spirits

Greg

 

[William Sommerwerck]

I had to look up methylated spirits.

To change the subject a bit... The origin of the word "alcohol" is
fascinating, among the most-interesting I've ever come across. Would you
believe that it's related to mascara?

http://en.wikipedia.org/wiki/Mascara

http://en.wikipedia.org/wiki/Alcohol

Ethyl alcohol is distilled from water/alcohol solutions, hence it is "the
fine part of" the solution ("fine" as in small, not good).

 

[Leif Neland]

Jeff Liebermann frembragte:

Note that cadmium is a hazardous waste. Dead NiCd batteries should be
properly disposed of, not mixed with the household trash.

Yeah. I once made a dumpster dive, when I discovered the boss had

dumped several boxes of used NiCd's in the regular trash. Don't ever do
that again, I told him...

Leif

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