Concrete dust

Johann Alcock <jalcock [at] slv__vic__gov__au> writes

>We are currently researching the effect of concrete dust on storage
>products, oils on canvas and object collections.  There appears to
>be very little written on this topic.  Has anyone had experience
>with collections that have been affected by concrete dust?  What are
>the issues that need to be considered in their treatment?   Where
>paper based storage materials are affected by concrete dust is it
>possible to clean them effectively or is it best to replace them?
>Any help would be appreciated.

>From a purely practical position, concrete dust is an abrasive. Any
functional object containing components that rub against one
another, be they rugs, books, or clocks or other functional object,
should be protected from these particles: the damage can be serious
and irreversible. Any dust can infiltrate into small voids and
crevasses and in the case of clocks or other objects that contain a
lubrication, can become part of the lubrication system ( thus
forming an abrasive fluid in the case of abrasive particulate or in
the worst case an "abrasive paste").  Hard particulate can become
imbedded into the surface of the bearing metal via the medium of the
lubrication and the pressure of the shafting against the bearing
surface or the particulate can reside in a crack or surface
imperfection and can serve as a "lap" to abrade the components in
much the same way that sandpaper will wear away wood. Any other
mechanical object capable of functioning ( such as sewing machines,
locomotives, automobiles, wagons, musical instruments) need to be
protected as well and for the same reason.

Embedded particulate or particulate suspended in the lubrication
cannot be removed by vacuuming. In general, embedded particulate
cannot be removed without damage to the surrounding material.
Particular attention needs to be taken with regard to the air
currents that flow through a building and what abrasive particulates
they are carrying. Air convection currents can introduce particulate
into the farthest reaches of an object. Thus if the outside casing
of an object is coated with an airborne particulate, for long term
safety, the object will need to be cleaned on the outside as well as
the inside. This may necessitate complete disassembly. Abrasive dust
is not good! Regards,

Jim Moss
Horological Conservator
James Moss Clockmakers, Inc.
Littleton, MA

                                  ***
                  Conservation DistList Instance 12:49
                Distributed: Wednesday, December 2, 1998
                       Message Id: cdl-12-49-007
                                  ***