Spraying Wei T'o solution

On behalf of a colleague, Lisa Fox <foxl [at] sosmail__state__mo__us> writes

I am posting this on behalf of a colleague who does not have access
to the DistList.

>    I am looking for ideas on methods of spraying Wei T'o solution.
>    First I tried the aerosol cans from the manufacturer. They clog
>    too often and result in a lot of waste. Next I tried buying the
>    solution in quart bottles and applying it with a Crown SpraTool.
>    This is a can of propellant that is attached to a spray head and
>    an 8oz. plastic cup to hold the solution. It was better (and
>    cheaper) than the aerosol, but far from perfect. There are still
>    some clogs, and the spray becomes uneven as the propellant is
>    used up or the can becomes chilled. Has anyone successfully
>    tried a paint sprayer or airbrush and compressor?

In the 1980's, using an earlier generic Wei T'o formulation, methyl
magnesium carbonate, which contained 80% freon, and may therefore
have different practical properties, we successfully used standard
low pressure spray guns and compressor within a fume cabinet.
Assuming the manufacturer's technical description was correct, we
measured something like an 80% by weight deposition of magnesium
carbonate in spraying stationery bindings/ledgers. I have always
assumed we were less efficient. The spray gun required daily
cleaning (soaking of working parts) with acetic acid as diluted
generic white vinegar, the spray booth sprayed with same monthly.

The freon, if I remember correctly, did not like aluminium or zinc,
and ate into some nozzle parts and the pressure vessel. Spray guns
were rotated frequently, lasted say a year, probably would have
required changing every 2 months or so if used constantly. This is
off the top of my head late at night; your colleague may email me
privately for further details.

James Elwing
Archive conservator
(now Powerhouse Museum, treatments mentioned carried out at Westpac
Archives, both Sydney, Australia)


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                  Conservation DistList Instance 16:2
                  Distributed: Thursday, June 20, 2002
                        Message Id: cdl-16-2-003
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