Exposure Unit Glass?

[Logoman]

I have an old National Exposure Unit that needs the Glass replaced. Anyone know what type this is glass this?

[ebscreen]

Tempered Starphire or other low-iron glass.

I believe Mr Kitson (maybe Coudray) has an article on ScreenWeb outlining
the details.

Measure ten times, cut once. Tempered won't be cut again.

[jvanick]

best glass for exposure units is Starphire ... but any low-iron glass should work fine.

note that tempered glass blocks a ton of UV (usually you can determine it from the edges having a green tint)

[ebscreen]

note that tempered glass blocks a ton of UV (usually you can determine it from the edges having a green tint)

Not according to Mr Coudray:
http://www.screenweb.com/content/selecting-right-glass-exposure-units

Page 3.

And I believe the edge tint actually defines iron content, which does block uv.
Our starphire certainly glows an actinic blue.


Which leads me to another question. In pics of led units the light appears to be
very much in the violet spectrum, or is that just a camera trick?

[jvanick]

note that tempered glass blocks a ton of UV (usually you can determine it from the edges having a green tint)

Not according to Mr Coudray:
http://www.screenweb.com/content/selecting-right-glass-exposure-units

Page 3.

And I believe the edge tint actually defines iron content, which does block uv.
Our starphire certainly glows an actinic blue.

Which leads me to another question. In pics of led units the light appears to be
very much in the violet spectrum, or is that just a camera trick?

I wonder if there's different grades of tempered glass... from a quick google (at least for auto glass):
"Tempered glass is designed to shatter into tiny pieces in order to protect the occupants in a crash. But unless they're tinted for privacy, side windows usually absorb only 65 percent of UV rays. That gives them an SPF of around 16, the same as some of the lowest grades of sunscreen"
 
technically 405nm (which is the output of many LED units) is actually in the lower end of the violet visible spectrum.

[ebscreen]

I'm pretty sure annealing is annealing. I'm no scientist but I'm not
sure how doing so would affect uv transmission either. Basically heating it up and putting it in tension.

At any rate I've had enough run ins with plate glass so as to never deal with it again, especially pieces
as large as we need.

The Oceanic aquarium company had to self-insure due to the number of serious accidents they had.