Conservation of toilets from shipwreck

Thanks to all those who have responded to our call for information
on the lead and ceramic shipwreck toilets.  Nicola Smith has moved
to another job, and I will be continuing the treatment.

To answer the queries raised by some respondents.  The toilets are
currently immersed in tap water not distilled or deionised water and
we are still getting corrosion, probably partially because our tap
water is naturally fairly soft.  The leather and iron together with
copper are part of the mechanism of the toilet flush pump and there
is no iron base.  We were reluctant to use sodium sulphate or other
lead inhibitors as we were concerned that these salts could enter
the body of the ceramic and crystallise after drying causing damage.
The toilets have been undergoing treatment since April 1996 and
chloride levels are still around 50ppm.  I suspect this unusually
slow rate of desalination is because only one side of the ceramic is
surrounded by water, the other side being covered with lead.  I
think we have almost got all the bugs out of our cathodic protection
system and it seems to be working successfully now.  I am happy to
go into more detail on this offline with anyone who is interested.

I am very glad to have finally tracked down the conservators of the
US Alabama toilets and look forward to discussions with them.

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                  Conservation DistList Instance 12:11
                   Distributed: Friday, July 17, 1998
                       Message Id: cdl-12-11-015
                                  ***