Re: PPG Starphire Glass ( ?? Questioning My Data)

Since I have not seen the data that was faxed to
Eric today by PPG I have no idea how it compares
to the data he provided back in 1999. However,
there is still a real discrepancy here with the
data. Last evening I sent to the list a link to a
data sheet from Precision Glass and Optics,
www.pgo.com. The specific link was
http://www.pgo.com/pdf/ppg_starphire.pdf.

Now, here is the thing. PG&O is one of the actual
fabricators of PPG Starfire glass. If you go to
the link above you will see that the information
they provide about this glass is very specific in
that it includes things such as available
thicknesses, chemical composition, electrical and
thermal characteristics, as well as transmission
from 330 nm up to 2100 nm. You really get the
impression that the folks who prepared this data
sheet knew their stuff. And I would think that if
anyone would know the real transmission data it
would be a fabricator rather than distributor.

Now, the plain fact is that the transmission data
provided by this fabricator of Starphire, at 5.6
mm thickness, is very different from what Eric
provided back in 1999, and I presume very
different from the data he was faxed today by
PPG, since he claims it is very close to his old
data.

So Eric's information is interesting, but it
hardly closes the case on the question of the
real UV transmission of Starphire. Course,
analysis by spectrophotometer would answer the
question and I hope to find someone to do this
testing.

BTW, if anyone would like to test the Starphire
glass against plain white float glass, which I
encourage, you can obtain a sample piece of
current production Starphire in 4" X 6" size by
calling the folks at PPG. I have also heard that
some Lowes stores stock Starphire, but have never
seen it in my area of the country. Just make sure
that the float glass to which you compare it is
of modern fabrication and has no coating.

Sandy

>After last nights back and forth, I was indeed going to call PPG.
>
>This required all of 3 minutes and a short wait for a return call. I
>received a call back from Penny Bridges. She has since faxed to me data for
>both the Starphire glass and SOLARPHIRE glass. The thinnest that the
>Starphire is listed as being manufactured is 1/8” or 3.3mm and all the way
>up to ¾. The data sheets do differ somewhat from those I received in 1992
>as one would expect; most businesses update their literature. I received
>separate sheets for 4mm and 8mm and this one combines the information and
>transmission data in 10nm increments and only shows transmission data for a
>glass with a thickness of 5.66mm. It does not show up on the available sizes
>but that is what is referred to in the chart.
>
>While it does not match my data, as one would expect from different
>thickness of glass, it does come darn close to the 4mm data that I have. It
>is not what I believe to be true as Sandy indicated in his email, but what I
>know to be true based on the manufactures data. Penny said that they have
>not changed it since they first starting making it but do offer a coating.
>
>It took very me little effort and would certainly have been something that I
>would have done if I were to include test information about a type glass in
>a book : ) But wait, that is what I DID back in 1992. It appears in my book
>on platinum printing. I don't site all the data. But do talk about why and
>when one might benefit from using it.
>
>
>This data also talks about the infrared quality of the glass. I have not
>studied gum like I have studied platinum/palladium printing. It may be that
>Judy's experience with Starphire has something to do with other
>characteristics of the glass that are not beneficial to the chemistry she
>used.
>
>
>At this moment, I can't lay my hands on them which does bother me. I took
>them out of my notes to make copies for some students and can't locate them.
>I do however, have the data for the 4mm which is what Sandy googled.
>
>I will however, be glad to post PDF's of the documents after I receive them
>in the mail. The faxes are OK, but I'd rather wait at least until I have a
>chance to print them with my higher quality printer. I am sure she'll fax
>them to you too Sandy.
>
>The PPG web site that I posted last night has their phone number. I suggest
>calling them.
>
>
>
>
>Eric Neilsen Photography
>4101 Commerce Street, Suite 9
>Dallas, TX 75226
>214-827-8301
>http://ericneilsenphotography.com
Received on Thu Nov 17 23:28:14 2005