Lead Rot Explained (was Re: LEAD ROT!)

On Sat, 8 Jun 2002 08:16:24 -0500 (CDT), DAWGFACE47@webtv.net wrote:

>GLENN, that is  lead  rot and it can spead to other  miniatures that
>come into contact with them!

I have this Usenet message saved. It explains Lead Rot. Funny enough,
the
message I saved was Glenn's; he quoted this information at the top of
his
reply on rec.games.miniatures.historical.

For an explanation of lead rot and what to do with it, check out:
http://www.dt.navy.mil/cnsm/lead_01.html .

It's the Curator of Navy Ship Models pages. They did an investigation
into the
cause of the corrosion, or "lead rot" in their lead model fittings.

This is a quote from their page: "The chemical process is: Acetic and
some
other acids, in the presence of carbon dioxide, catalyze with lead to
produce
lead acetate and lead hydroxide. Lead acetate and lead hydroxide
together
react with carbon dioxide and form lead carbonate. Lead carbonate then
releases acetic acid and the process becomes self-sustaining. It is
important
to recognize that the formed lead carbonate is not just a substance
clinging
to the surface of a casting, it is the surface of the casting
transformed to
powder. For practical purposes, a portion of the lead is gone and lead
carbonate is left in its place. The lead carbonate releases acetic acid
which
can continue the process until the lead part is progressively consumed
from the outside, inward."

The purity of the lead dictates the susceptibility of the item. Pure
lead is
very susceptible to it. On the other hand, most miniatures are either
lead
mixed with some amount of tin or some amount of zinc, if I remember
correctly.
Pewter is far, far less susceptible to this than, say, pure lead
sinkers.

The site gives a long list of sources of acetic acid as wood --
particularly
hardwoods -- and most oil based paints and varnishes.

>From their list:
- PVA glue or "white glue" (notice how white glue has a faint "vinegar"
smell?)
- contact cement
- plastic wood
- latex varnish
- "natural" varnish
- polyurethane varnish
- tung oil varnish
- linseed oil varnish
- enamel paint
- oil-based paint
- lacquer paint
- varathane paint
- oil-based stain

The biggest way to help stem the onset of lead rot is to store the
figures
with a minimum amount of ventilation. From the chemical process, storing
them
in sealed containers lets them "stew in their own juices", so to speak.
This
is probably why the Star Frontiers ships have so much lead rot, as they
were
shrink wrapped and they had a very high lead content. Cutting off the
part
with the rot, painting, and sealing the figure could go a long way to
preventing the rot as well (as you make an air tight seal so that the
lead
doesn't come in contact with acetic acid).

And to think, years ago someone told me to use vinegar on my lead to
clean
them, and I know of folks who painted their minis with Testors enamel
paint...

(A tip of the hat to Hal Smith, from whom I stole/rewrote much of this
e-mail
message.)

Allan Goodall		       agoodall@hyperbear.com
http://www.hyperbear.com

"At long last, the earthy soil of the typical, 
unimaginable mortician was revealed!" 
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