Re: Beware of old AntiStatic foam


stevenhorii
 

Thanks for the suggestions for the Xcelite handles! I will try them out. I
did try an “antifungal” treatment that worked for a while, but the white
cast came back.

On batteries - I now use rechargeable AA and AAA cells (I like the
Panasonic Eneloop) - these are nickel metal hydride. Never had any leakage.
The only downside of the NiMH chemistry is the 1.2VDC output. Devices that
don’t like a lower voltage (smoke detectors!) may warn you of a failing
battery. There is also a AA cell called a Tenavolts that is rechargeable
and has an output of 1.5VDC. I am not sure what their chemistry is because
most lithium chemistry cells are usually 3.6V but these are a single cell -
no “dummy” needed. They are also rechargeable. They do tend to have a very
flat discharge curve, but when they start to drop in voltage, they drop
fast. The Tenavolts cells come with a charger and I am not sure if other
lithium chargers will work. The Tenavolts cells are also very slightly
larger in diameter than the NiMH and alkaline cells - they will not fit in
at least one of the smoke detectors I have. I have also used the Tenavolts
now for about two years and no leakage problems - but that’s not a very
long time. The Eneloop cells are low self-dicharge cells, so they will
retain their charge for months after a full charge unlike older NiCd and
some NiMH cells. These are sometimes called “precharged” cells because they
come charged and you can use them right out of the package.

On recharging, I use chargers for the NiMH cells that allow a selection of
charging current. Fast charging tends to shorten the lifetime of the
batteries, so I use “soft” charging or 180-200 mA.

Most of the rechargeables do not have the current capability of alkaline
cells, so they won’t last as long in high current drain devices.

On Sun, Mar 21, 2021 at 17:38 - <rrrr6789@gmail.com> wrote:

Steven said:

Another “plastic rot” question. I have a set of Xcelite tools. One of them,
a stubby Philips screwdriver, developed a white coating on it that was
impossible to remove without sanding it off. I could get some of it off,
but it kept re-developing this. None of the other tool handles has done
this. The handles, I believe, are a butyrate plastic that gives off butyric
acid as it oxidizes but they all are and this is the only one that
developed this white coating. The whole tool kit smells rather like vomit
(my wife refers to it as my “vomit tool case”) but this is common with
butyrate plastic-handled tools.

That butyrate plastic deteriorates into butyric acid and yes, I'm told
that that is what gives vomit it's nauseating smell. It's similar to, or
the same, compound found in milk that is going bad so human reaction to
that smell is thought to be a survival mechanism. I soak those old Xcelite
tools in full strength household ammonia and then scrub them with a brass
bristle brush or a tough nylon pot scrubber and that will remove the white
film on the tools. You may need to repeat the process a few times.
Surprisingly, even a brass bristle brush doesn't seem to harm or to scratch
up the plastic handles (YMMV!) I've cleaned several dozens of Xcelite
tools like this over the past 6 or 7 years and I've never found any sign of
damage by cleaning that way.

On Sun, Mar 21, 2021 at 2:49 PM stevenhorii <sonodocsch@gmail.com> wrote:

I think polyethylene foam instead of the black polyurethane foam does not
have the “get goopy and stick to everything” problem. Has anyone had
polyethylene foam degrade like the black stuff? I have not - either black
or white polyethylene has stood the “test of time”. I have seen foam
rubber
turn to dust, but at least it does not (in my experience) get sticky.

Apparently the polyurethane foams also outgas as they degrade and this
can
leave deposits on stuff - think camera optics as many camera carrying
cases
use polyurethane foam.

If I have some custom-fitted black foam in a transit case, I put the item
in a plastic bag and before putting it back in the case.

Another “plastic rot” question. I have a set of Xcelite tools. One of
them,
a stubby Philips screwdriver, developed a white coating on it that was
impossible to remove without sanding it off. I could get some of it off,
but it kept re-developing this. None of the other tool handles has done
this. The handles, I believe, are a butyrate plastic that gives off
butyric
acid as it oxidizes but they all are and this is the only one that
developed this white coating. The whole tool kit smells rather like vomit
(my wife refers to it as my “vomit tool case”) but this is common with
butyrate plastic-handled tools.

A comment on Duracell batteries. I am pretty sure there are counterfeits
out there - particularly the “bulk packs” with no Duracell label on the
outside. Here’s an article on fakes:


https://www.thecounterfeitreport.com/product/106/Duracell-Coppertop-AA---AAA-Batteries.html

When I have had Duracell batteries (the AA ones in particular) leak, on
checking, they were the ones I bought in unlabeled bulk packs. I
generally
remove batteries from equipment I am not going to use frequently.

Steve Horii

On Sun, Mar 21, 2021 at 12:01 Harvey White <madyn@dragonworks.info>
wrote:

As I've mentioned previously, the latest run of Duracell (guaranteed
not
to leak before 10 years) does exactly that, and often in the package.

The good news is that they will often give you money to replace the
damaged item if you call them. Their warranty is "repair or replace",
but you do have to call.

I've had the foam in probe cases crumble, (both HP and Tek), anti
static
foam corrode and crumble, etc...

Harvey


On 3/21/2021 9:50 AM, David Slipper wrote:
Nasty!! I wonder what other time-bombs are awaiting us!?

I'll certainly be checking my stock of bits and spares.

I always assumed that a famous brand of NiMh batteries were supposed
to be leak proof - Hah! I nearly lost a pair of nice walky-talkies
and
a multimeter that way, so now cells get removed from rarely used
items
and I make a point of checking torches and the like regularly.

Sadly not surprised at anything these days,
Dave


On 21/03/2021 13:07, - wrote:
Well, this thread just showed up on EEVBlog. This is exactly the
kind of
damage that I used to see happen to IC and to TE accessories that
were
stored in the old antistatic foam.

<
https://www.eevblog.com/forum/chat/beware-of-old-antistatic-foam/?topicseen




















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