From: REMOVE_THISdwilkins@means.net (Don Wilkins)
Newsgroups: rec.crafts.metalworking
Subject: Re: Removing aluminum rod stuck in rifle bore
Date: Mon, 06 Dec 1999 16:09:54 GMT

On Sun, 05 Dec 1999 18:32:13 -0500, Glenn Ashmore
<gashmore@mindspring.com> wrote:

>
>
>Bray Haven wrote:
>
>> Also was put on open wounds as Mercurchrome and (I think) Merthiolate.
>
>I believe that Mercurichrome is mercuric oxide and that IS deadly.

No.

Mercurochrome is a trade name for merbromin. If anyone is interested
merbromin is dibromohydroxymercurifluoriscein disodium salt (from
mercuric acetate and dibromofluorescein). It is not particularly toxic
(externally).

>Over a long period of time, mercury vabor causes brain damage.  The
>expression "Mad as a hatter" comes from the fact that hat cleaners used to
>use mercury to clean hats.  Over time, their personalities  became rather
>"quaint" .

Mercury vapor does not pass the blood brain barrier and therefore the
problem is considered reversible. There are/were a number of
industries where lengthy mercury exposure was routine e.g. felt hat
production, mercury thermometer manufacture, and mercury mining. The
workers would develop characteristic symptoms and would routinely be
pulled off the job to alleviate the symptoms. The miners in Spain
routinely were placed in hot rooms during this "drying out" process to
increase their fluid intake and  output to hasten the mercury removal.
(so they could return to work faster)

Organic mercury poisoning is a different beast and there have been
some real horror stories. The Mimata Bay incident was caused by
dumping the effluent from a plastic plant directly into the bay.
Unfortunately there was a lot of mercury acetate present and over time
much was converted to methyl mercury. Methyl mercury concentrates in
the fish and the diet of these people contained a great deal of fish.
The symptoms were first noticed in the cats but it wasn't long before
the people were also in pretty bad shape.

Methyl mercury does pass the blood brain barrier and the damage is not
reversible.

Most of the problems in North America have been from cloro-alkali
plants. The problems here also resulted from eating a high fish diet.

Mercury compounds used to be used as a fungicide on seeds. Some may
remember the pinkish seeds. There was one instance where a seed supply
house sold the left over seed to a farmer (after planting season) who
unfortunately fed it to his hogs instead of planting it. The hogs were
butchered in the fall and disaster struck within days.Those that
didn't die may have wished they had if they could have seen what
happened.

In this discussion I wouldn't be worried about the mercury poisoning
but I would be concerned about contaminating a home or shop with
spilled mercury.

The mercury scare hit in 1974 and I was quite involved as we had a
small particle magnet plant which produced magnets by
electrodeposition in mercury. This was before EPA amounted to much but
it sure changed the  influence of EPA regulations.

They started a mercury decontamination program at our facility and I
don't believe there was a single trap (lab drains) which didn't have
substantial mercury present. There were little puddles behind most of
the lab benches as well. Chemistry as practiced in the lab changed
drastically as EPA and OSHA flexed their muscles.

From: REMOVE_THISdwilkins@means.net (Don Wilkins)
Newsgroups: rec.crafts.metalworking
Subject: Re: Removing aluminum rod stuck in rifle bore
Date: Mon, 06 Dec 1999 16:09:51 GMT

On Sat, 04 Dec 1999 01:35:29 GMT, "David Berryhill"
<dwberryhill@earthlink.net> wrote:

>A customer brought in a rifle (Remington 700) with a piece of aluminum
>cleaning rod stuck in the bore.  He had a case stuck in the chamber and
>tried to drive it out with the cleaning rod.
>
>I removed the cartridge from the chamber but that rod is still stuck.  I
>tried to drive it out with a piece of drill rod but it is really stuck!
>
>Any suggestions on removing this?  It's about 12 inches and it is stuck in
>the chamber end of the barrel.  Is there a way to chemically dissolve the
>aluminum rod without harming the steel barrel?

As a chemist I would like to put my vote in against using mercury
here.

Aluminum is slightly soluble in mercury (0.003 wt%). The reason that
mercury can behave like cancer with aluminum is due to the reactivity
of the aluminum in the amalgam. One doesn't ordinarily think of
aluminum as a metal that amalgamates but by definition it does.

Aluminum is normally protected by an oxide coating which inhibits
oxidation. If that oxide coating is removed aluminum is a fairly
reactive metal and rapidly reforms the metal oxide on the surface.
Mercury will not usually penetrate that coating but once mercury gets
contact (by a scratch or nick) with the aluminum it can be devastating
as the mercury dissolves an extremely small amount of aluminum and the
aluminum in the amalgam reacts with moisture to form an oxide or
hydrous oxide. This latter reaction depletes the aluminum
concentration in the amalgam so over there at the aluminum-mercury
interface a little more aluminum dissolves and the reaction behaves
like an aluminum pump. The process is kept active because the mercury
is preventing the fresh surface from forming the protective oxide
coating. Even though there is very little aluminum in the amalgam at
any given time the process keeps kicking a small amount of aluminum
from the metal to an oxide.

Note that you are not going to end up with a whole bunch of aluminum
dissolved in mercury. The mercury is just a conduit to transfer
aluminum from the metal to an oxide. In other words a little bit goes
a long way and filling the hole with mercury would be counter
productive.

All looks good so far but I fear that the process is going to be very
slow. At any given time there is only 0.003% Al in the Hg and it must
diffuse through the mercury to get oxidized at the mercury air
interface. Not a fast process. If you go this route do it where you
aren't going to contaminate living quarters or shop with spilled
mercury. This would not be my choice.

The case separation (one reload too many) may complicate or help here.
It may be that the rod is stuck because of the remaining case. If so
both zinc and copper should dissolve in mercury. Again not a very fast
reaction. The use of mercury by gunsmiths is to remove lead and in
this case there is much more surface area so the reaction is faster
and of course lead is quite soluble in mercury.

So much for mercury on to other suggested chemistry.

One of the more difficult chemical reactions is one that is confined
in a hole. It is difficult to remove the reaction products, the
reaction stops as soon as you use up some of the reagent, and you have
difficulty getting fresh reactant to the place it is needed. This
means one is constantly removing spent solvent and replacing it. A
step that leads to spills and spreading the solvent around in places
you don't want it.

I hated these when they came in the door. (Not gun problems but
removing one metal and not react with the other.) When the offending
metal is in a hole or on a surface not to be disturbed I wished I was
on vacation.

Another approach could be to try anodic dissolution. I visualize two
routes here but the experimental setup is the same for either.

Equipment:

l. about 3 volts of dc current from a battery or power supply,
electrolyte solution, some wire and two battery clips. Three volts
should be plenty and more is not necessarily better. Perhaps 100-200
milliamps for a start.

Hookup:

connect the plus side of the power supply to the aluminum rod and the
minus side to some copper wire which you can insert into the breech
without shorting to the chamber. Insulated number 10 with about an
eighth inch stripped should work.

Route 1. Dissolve the casing (brass)

Household ammonia would be the most effective electrolyte. This will
keep zinc and copper in solution. If it runs blue you are dissolving
copper. For the picky yes a cyanide would be better and probably what
I would use in the lab but it is not what I recommend here.

Route 2. Dissolve the aluminum.

Use a caustic (NaOH) solution. I would use something under 10%. This
will dissolve aluminum and zinc but copper and iron should be
relatively non-reactive.

If you push it hard enough (more volts) you will get some gas
evolution which will help stirring. The ammonia solution should start
as soon as current is applied since ammonia will clean the brass
surface. The NaOH solution may require scratching the surface of the
aluminum.

You can dissolve some iron this way but the predominate reaction
should be dissolution of brass or aluminum.

In either case I would set up a spring under tension at the other end.
I would use as much tension as I could get pulling on the rod. This
could be done either by using threads on the rod (and a nut) or by
drilling a hole through the rod and inserting a pin after compressing
the spring.

(Comments from my friendly pawnbroker friend.)

I discussed this with a friend who knows more about guns than anyone
else I have ever met. He said this is a job for a gunsmith before any
more damage is done. He said they have the tools (long drills, etc.)
to do this type of job. I presume you are a gunsmith but if not you
might consider consulting with a good one.

From: REMOVE_THISdwilkins@means.net (Don Wilkins)
Newsgroups: rec.crafts.metalworking
Subject: Re: Al in Hg:  Was rod in rifle bore
Date: Tue, 07 Dec 1999 16:12:51 GMT

On Mon, 06 Dec 1999 21:45:45 GMT, inet@intellisys.net (brian whatcott)
wrote:

>In article <384bf04c.2431293@nntp.ix.netcom.com>, mklotz@alum.mit.edu
>says...
>>
>>  The vapor
>>pressure of Hg must be very high.
>
>You mean low, I'm sure.

Nope he should have meant high and compared to other metals it is
high.

One cubic meter of air (1.3 kg) saturated at 20 degrees C contains 14
mg of mercury. Offhand I can't think of any other metal with that high
a vapor pressure at room temperature. It is a whopping 2.4 grams of
mercury per cubic meter at 100 degrees C.

With those numbers you can see why in the past the miners were placed
in hot rooms to "sweat out" the mercury. Of course in the hot room
there was also a lot of sweating, fluid intake and fluid output in
addition to the more favorable saturation in air numbers.

My recollection (not looked up) is that the EPA limit for mercury in
air is 0.1 mg per cubic meter.

It is absorbed through the lungs quite rapidly but it takes long term
exposure before the characteristic symptoms appear. Fortunately
inorganic mercury poisoning is reversible in most cases. Not so with
organic mercury poisoning.

The problem in fish occurs because elemental mercury is converted to
methyl mercury in lakes. The methyl mercury is concentrated up the
food chain and people who consume a lot of fish are vulnerable. Methyl
mercury poisoning is not reversible.

The tendency of mercury to break into minute spheres when spilled
increases the rate at which saturation occurs. If you open a bottle of
mercury in a room it is not long before you can detect it in the air.

My concern was that the fellow would contaminate his home or shop with
mercury. That could lead to chronic health problems, expensive
cleanup, reduced resale value, or all three. Casual exposure to
mercury such as most of us received as youngsters should not be a
problem.

One of the early symptoms is an irritating personality which may
suggest some of us have had more exposure than others.

From: REMOVE_THISdwilkins@means.net (Don Wilkins)
Newsgroups: rec.crafts.metalworking
Subject: Re: Al in Hg:  Was rod in rifle bore
Date: Wed, 08 Dec 1999 17:21:35 GMT

On 07 Dec 1999 11:57:32 EST, Jim <jrnaylor@concentric.net> wrote:

>In article <384CB999.7A9EDEF8@netlabs.net>, Demon Buddha <osan@netlabs.net>
>wrote:
>
>> It wont kill you right off the way a lungfull of phosgene
>> 	will, but it accumulates in tissues and organs and will
>> 	wreak havoc with memory and many other functions.  I don't
>> 	think there is much of a way to be too careful with it.
>
>You're probably right, since I've forgotten how old I was when I amalgamated
>all those pennies and dimes (dimes used to have a silver cladding, and I
>can't remember when they changed) by *gasp* rubbing the nasty stuff in with
>my eight or nine or ten year old fingers fifty years (or so, who knows?) ago.
>
>As for a minimum acceptable exposure level, how could they even pretend to
>do any direct research or find enough reliable exposure data to know (or
>guess) what that level would be. And even it it *were* available, be able to
>put it in the practical terms that would apply to the infinite number of
>scenarios that you find when people actually use their own common sense to
>control the risk. Why am I not surprised it isn't on an MSDS?

They don't set the limit based on people's common sense to control the
risk. It is based on a level which is expected to give a safe working
environment to those who are hired and are not in a position to assess
or control the risk.

I doubt if there was much (if any) deliberate exposure to determine
acceptable limits. It is not too difficult to measure the amount of
mercury in a person. It is also fairly simple to measure the amount in
the working environment. Air monitoring is routine. There would be
vast amount of data available for known exposures and health records
to come up with a "limit".

You crank the level lower until you reach a point where there are no
known problems. It may be like that old method used to adjust ski
bindings. You keep tightening until the ski doesn't come off. If you
fall and break a leg because the binding didn't release then you
backoff a notch or two.

I suspect regulations on mercury are based on the rate of increase of
mercury loading compared to the average rate of mercury elimination
(primarily urinating). If  the body is loading mercury faster than it
is eliminating mercury then the person could be heading for trouble. I
would presume "acceptable level" was probably determined by someone
who was not one of those being exposed to mercury. Who knows if the
regulations provide a "safe" limit? In any case it is better than no
limit at all.

A good many years of my employment were prior to the government (USA)
becoming concerned with worker safety. I was amazed at how many of the
chemicals I used should have caused my early demise. On the other hand
there are too many cases where workers would be subjected to
unnecessary hazards without some type of regulations. Sometimes they
do go ballistic making mountains out of mole hills.

Until recently I had been consulting for a company that recycles
fluorescent lamps. The workers there are checked on a regular basis.
If their mercury levels exceed a limit they are assigned to a
different work area (or sent home) until their mercury loading returns
to an acceptable level. Those workers who were at the front end of the
process probably never heard of mercury before they came to work. Hell
it is difficult to keep the safety masks on them during hot weather.

As far as elemental mercury is concerned I would not want a mercury
spill in my home. You don't need to cover the entire floor to get a
saturated atmosphere. Preschool children are in the home most of the
day and that exposure may be too much. It certainly would be safe
while it is in a closed bottle but it is too easy to spill. As a
result I won't keep it in the home.

My lab space for almost 50 years probably had mercury lurking in many
nooks and crannies. With the exception of an irritable personality I
am not aware of any adverse affects.