>Please check this with an archaeological conservator first, as they have
>the best data on the lifetime of polyurethane foam and it is not very
>long. It also has the potential of releasing undesirable breakdown
>products. Many people have used this because it sets in place as a space-
>and gap-filler, but it is a short-term solution to a long-term problem
>and the headaches may outweigh the immediate benefits. I believe that
>exposure to UV sharply decreases its useful life, too. Please, again,
>talk to an expert first.
>Sally Shelton
>Director, Collections Care and Conservation
>San Diego Natural History Museum
>
>Sally,
 
We built almost all the flowstone formations in the cave at the Arizona -
Sonora Desert Museum with foam (coated with a thin layer of resin), and
they are still in good shape almost twenty years later. You are certainly
right about UV breakdown and bad fumes when you spray it. There are a
number of UV filtering coatings that may be applied if UV is a problem. We
put UV sleeves on our lights, as well. I should have explained this, but I
was in a hurry at the time.
 
There are probably many new state-of-the-art techniques that are much safer
and better. I'm an old-timer and was just suggesting something that had
worked so well for me.
 
Regards,
        Robert
 
 
Robert O. Dahl
Interpretive Designer
8421 N. Via Tioga
Tucson, AZ 85704 Ph:(602) 797-4752
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