Flexible magnets

Timothy Greening <timothy.greening<-at->gov<.>sk<.>ca> writes

>Has anyone had experience using flexible magnets (like fridge
>magnets, often comes on a roll with an adhesive for labels) inside
>enclosed storage or display units, over the long term?  We are
>thinking of using them to label drawers in tightly sealed metal
>storage cabinets, but are wondering about possible issues arising
>from off-gassing.  One manufacturer we spoke with says the material
>is a rubber polymer.  Is anyone aware of flexible magnet tapes made
>of a material more suited for long term storage?

I have seen the use of flexible magnets used as labels inside
storage cabinets.  I believe that this is a good use for them as
that they can easily be repositioned as the contents of the cabinets
are changed as artifacts are shifted.  They are also used as
closures for book wrappers.  In both cases, collections are exposed
to any possible threat.

Flexible magnets are not just rubber polymer, in fact they encompass
a large group of varied types.  Besides their thickness, one can
select one of four pole directions within a sheet.  They are all
bonded in a polymer that is either compressed or injection molded.
The ferrite powder that is the most common, and least expensive, is
found in both synthetic and rubber, whereas the more expensive rare
earth ores are found only in the synthetic polymers.  A major
supplier here in the US, only sells flexible magnets in a
rubber-base material, perhaps similar to the one you described.  The
sales rep I spoke with called it 'Hypolan', or 'Chlorosulfonated'
polyethylene.  Sadly, he did not expand on any other information and
did not know about off-gassing.

The extent of off-gassing should be tested for all of us to know, it
is clearly important, especially with magnets being used more often.
Perhaps we could encourage a museum or lab to test them.  In the
mean time, I do not think I would use them in cabinets that house
silver artifacts.  But for most cases, they theoretically might not
off-gas any more than the artifact's own materials.

Gwen Spicer
Spicer Art Conservation, LLC
518/765-2142


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                  Conservation DistList Instance 28:32
                 Distributed: Friday, January 16, 2015
                       Message Id: cdl-28-32-001
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