Sorry to drag this thread up again, but I'm still feeling a need for penance for my off-the-cuff condensation comment.

The cover article in the February 1999 issue of NCPTT Notes reports on a glass conservation workshop.  In it, reference is made to a 1994 PTTGrants project on protective glazing for historic stained glass windows, project director Neal Vogel.  Perhaps this could be a resource for further information.

Go to the NCPTT web site at this link and scroll down for detailed information on the report. <http://www.ncptt.nps.gov/notes/28/7%5Ffs.stm>  

It's item number 7.

See also item number 10 at <http://www.ncptt.nps.gov/notes/24/3%5Ffs.stm>

Go to this link to order publications, I believe they are free <http://www.ncptt.nps.gov/sitetools_order_fs.stm>

If you haven't explored the NCPTT site, you should.  It's a goldmine, and just about the most excellently constructed, easy to navigate and know where you are site I've found on the web, bar none.  Home page is <http://www.ncptt.nps.gov>
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Dan Becker, Exec. Dir., RHDC
Raleigh Historic Districts Commission
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