UV filters

Deborah Lee Trupin <deborah.trupin [at] oprhp__state__ny__us> writes

>We are looking to replace 10-12 year old UV filtering films at one
>of our historic houses.  In the course of getting quotes, we have
>suppliers offering us either the 3M, which is what we have used
>before, or Vista (aka Courtauld).  The Vista sales people are
>stating that their film is much superior.  From reading their
>literature, it seems they use a different adhesive system which they
>call CDF (Clear Distortion Free) vs the PSA (Pressure Sensitive
>Adhesive) in the 3M.  The Vista lit also says that they build the uv
>absorbers into the film, whereas the others include it in the
>adhesive, which makes the others break down more quickly (again, per
>the Vista lit).
>
>In comparing the amount of UV blocked, glare reduction and solar
>heat reduction, I find little difference between comparable levels
>of the two films.
>
>Does anyone have less partial information?  Or, experience with
>longevity and suitability of the Vista/Courtauld film for historic
>houses?

I was wondering if Peebles Island knows something about adhesive
films for window panes that the Trust hasn't dealt with yet. We
don't advocate that our historic sites use the film, because it
causes so many problems on removal. At Woodlawn, film was placed on
windows about 10-12 years ago, and because of major changes in their
administration, the film was "forgotten" and left on too long. The
adhesive basically cooked, and the staff had the devil of a time
removing the old film, even with advice from 3M re removal
techniques. So much so that historic window panes were broken, and
we in fact had to have the frame of one window removed and fixed
because of damage. We now only allow the Trust's sites to use roller
blinds made from film, individual panes of UV plexi for each light
(put in with glazier's points), or else a single, large sheet of UV
plexi that goes over the entire window. While these all do cause a
couple of holes in the wooden frames, they are much easier to deal
with than reglazing with historic glass!

I would appreciate hearing your thoughts on this topic, as we are
always getting inquiries about this question, so I like to have as
much information available in the "public vertical files" that we
maintain on technical info. for other sites and private homeowners.

Melissa M. Heaver
Director-Museum Collections
National Trust for Historic Preservation


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                  Conservation DistList Instance 14:2
                  Distributed: Thursday, June 29, 2000
                        Message Id: cdl-14-2-012
                                  ***