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John Robertson John Robertson is offline
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Default Removing battery corrosion

On 2018/02/11 4:51 AM, wrote:
On Sunday, February 11, 2018 at 5:53:57 AM UTC-5, wrote:
I got an old AM-FM pocket transistor radio which looked good and clean
till I opened the battery compartment. Very corroded carbon zinc
batteries were in it. After removing them, I cleaned off as much of the
corrosion as possible by scraping with a plastic stick, and scrubbing
with q-tips and rubbing alcohol. That got rid of most of it, and I was
surprised to find the battery clips are not badly damaged, but I had to
use a fingernail file (sandpaper strip) on the ends of the springs.

Better yet, the radio works perfectly.

But there is still a little of that battery corrosion still in there. In
all the years I've worked on electronics, I have never found a perfect
way to clean up leaked batteries. Is there some sort of spray or a
chemical that will dissolve or deactivate that crap?

Of course it has to be safe for the circuit board and components too. I
use the 91% isopropyl alcohol, so it evaporates quickly and leaves
little water residue behind. (Then leave it dry well before use).

My sovereign cleaning method for this is to use a very strong concentration of baking soda mixed into distilled water. About a tablespoon of soda into a teaspoon of water to make a paste. This will neutralize any corrosives from the batteries - but the material is highly conductive in its own right. So, after application with a small toothbrush or spiral brush, rinse again as yo have with distilled water, then alcohol to displace the water.

No, no, NO! Sorry Peter, you missed this one. And your advice is
normally spot-on!

Batteries use an AKALAINE (a base not an acid) so using another alkaline
product (baking soda) will only exacerbate the problem.

To neutralize a base (alkaline battery leakage) you need to use a mild
acid. Get some white vinegar and mix with distilled (if your water is
hard) water 50:50 and use that solution to wash the residue away and to
stop incipient leakage from continuing.

I wrote up a page back in the late 90s after talking with an engineer
from EverReady about battery leakage:

If severe, and the alternative is landfill - I have been known to run an entire chassis through the dishwasher (one without an exposed Calrod), or use a bit of lye-based oven cleaner on a cotton swab - again rinse carefully when done. Needs must when the devil rides.

Um, again you are recommending using a base to try and arrest the action
of another base... Lye is a strong base, and bases are what are used to
etch circuit boards, eh?

Running circuit boards through dishwashers can be fine, just skip the
detergent! Seal DIP switches, pots, relays, etc. first...

Peter Wieck
Melrose Park, PA

John :-#)#

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