Guns and swords

On behalf of Linda Badger, Pam Winstead <winstead [at] ismhs__org> writes

>    What is the proper way to treat metal objects such as firearms,
>    swords, tools, etc. that may or may not have been handled by
>    persons not wearing gloves?

Metal objects stored in museums don't behave in the same way as
metal objects that are in constant use. It can be difficult to
convince people that handling metal museum objects with bare hands
can be destructive. You are often faced with comments like "I've
been using my tools with bare hands every day for x years and they
have never corroded", and they are usually correct. In the short
term, human oils, silicone oils and mineral oils are all protective.
The more often that they are applied, the less likely the occurrence
of corrosion. The problems really start when handling becomes
infrequent. Human and mineral oils oxidise and form acids and salts
that can be very corrosive. Human oils oxidise faster than mineral
oils, and are more corrosive. Both oils also attract dust, which is
often corrosive and attracts moisture. In most cases, the more
highly polished a metal is, the more likely it is to corrode due to
infrequent handling. The silicone oils cross link and form an
insoluble film that can be very difficult to remove later.

In most museums metal objects are not handled very regularly, and
the resources don't exist to be enable cleaning of metal objects on
a regular, frequent basis. The use of gloves when handling metal
objects should be encouraged. Ideally, metal objects should be
degreased, thoroughly cleaned and coated with a wax or lacquer, as
appropriate. Generally speaking, at the Australian War Memorial we
apply microcrystalline or polyethylene wax to ferrous objects, and
Incralac acrylic lacquer to polished copper, brass, silver, gold
etc.

Another good reason for wearing gloves when handling museum objects
is that you never really know what is on the surface. In older
museums some very nasty insecticides have be used over the past
hundred years. Arsenic trioxide and DDT are two such compounds.
Both are very poisonous and they take many decades to breakdown, so
if these compounds have been used in your museum in the past,
chances are that they are still around.

George Bailey
Objects Conservator
Australian War Memorial
Treloar Centre for Conservation
4 Callan St, Mitchell, A.C.T. 2911
Australia
+61 2 6243 4440
Fax: +61 2 6241 7998


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                  Conservation DistList Instance 13:37
                  Distributed: Monday, January 3, 2000
                       Message Id: cdl-13-37-001
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