UV filtering materials

Heather Pigat <heather.pigat<-a t->utoronto< . >ca> writes

>... would like to hear from those of you who have employed UV films
>on the window glass.  Our concern is the heat gain on the glass,
>which has caused the glass to break.  Any and all insights and
>advice would be gratefully received.

We install UV film in client locations ten to fifteen times a year
here in Florida because the UV is devastating; Palm Beach is
actually 400 miles south of Cairo, Egypt with all that implies.  UV
here is 12,500 nanowatts per lumen, so any film we use must be
robust.  We have used Llumar clear film (99.9% uv filtration) for
15+ years without any problem.  It is crystal clear, and does not
distort color.  We have never had any issue with heat gain damaging
glass, probably because in its crystal clear form there is nothing
to hold and build up heat.  A word of caution: we have had serious
failures with 3M film.  Despite their warrantee, we have seen
multiple premature total failures in 3M in as little as a year; in
Llumar we have had none in the years we have been using it (we
conduct annual measurements on several collections with our Elvec
meter).  Adding to the horror of this is that often the 3M failure
is not identified until the material being protected begins to fade.
3M has an explicit disclaimer that it is not responsible for any
fading when its film is in use.

In regard to your pictures which cannot have plexi placed in front
of them; is it a framing issue or a materials issue?  If it's a
materials issue, would a double pane, heat tempered bonded glass
work?  The bonding adhesive is, serendipitously, one of the most
effective UV filters I've ever seen.  There are several absolutely
sensational ones on the market, and we often use them to frame works
on paper with delicate lines because you can actually see the
delicate lines more clearly through this glass than "Museum Glass",
or plexi.  How many times in your life do you get to use the word
"serendipitously"?

Gordon Lewis


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                  Conservation DistList Instance 28:8
                   Distributed: Friday, July 25, 2014
                        Message Id: cdl-28-8-003
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