Does anyone know if this will meet FDA impact standards, and at what CT?
B
Does anyone know if this will meet FDA impact standards, and at what CT?
B
Oh lord Barry. Last time I asked a question similar to that and where they got their information from I was blasted for not taking peoples answers at face value. They were insulted and wanted apologies because I wanted to know WHERE they got their information. I was even accused of being "cheap" for not having a ANSI Standards book at my finger tips......I do, its called a computer. Look and ask from all sources.
So best of luck with that one.
As far as I learned high index glass was never impact resistant .....................
Originally Posted by Barry Santini
As far as I learned high index Flint glass was never impact resistant and very very brittle, and has to be worked with gentle gloves and worn by careful people.
Heavy flint
ZEISS Single Vision
- Sph Mineral 1.7
- Sph Mineral 1.8
- Sph Mineral 1.91.706
1.800
1.89339.3
35.4
30.4High-index material for high prescriptions. Additives include titanium and lanthanum. In 1973 Schott received an award for being the first company to develope these lenses
http://www.x-celoptical.com/chemtempering.php
Double the cycle time (32 hours) for 1.80. Is this Schott SF-6?
The minus power 1.80's that I fit were about 2.2mm CT.
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
Ummm...Luzerne has it as well plus 1.60 and 1.70.
I think that the Abbe for the 1.8 index glass is around 28...yes?
I, who used to specialize in hi-index glass, will not touch these.
B
Up here a Zeiss 1.8 has a 35 abbe
B,
Are you planning on new drill Silhouette job?
Nah........I'm thinking Minima!
Hi index glass abbe values are dismal, they are brittle and unless you're a glass blower, x-ray technician or (strangely enough) a dairy farmer - glass lenses are rotary telephones. Plastic equivalent lenses are superior to all but the shamelessly careless. If you're interested in high-index glass you're ignoring better alternatives.
Here's a -15.50 I did in a Zeiss 1.8 That's what the client wanted. He was familiar with alternatives. Turned out pretty good.
Very nice.Here's a -15.50 I did in a Zeiss 1.8 That's what the client wanted. He was familiar with alternatives. Turned out pretty good.
Just curious- Can you plug in the numbers in a thickness calculator and tell us how much thicker a 1.74 would be?
My biggest concern would be in the event of an airbag deployment how they'd resist cracking although thinking about it you'd probably not be able to keep your eyes open when you crash.
Last edited by Uncle Fester; 09-04-2014 at 09:49 AM. Reason: spelling...
A 174 wouldn't have been that much thicker. Still would have looked great. I've actually seen a 1.9 with a 1mm centre after a direct airbag impact. It split but was still intact in the frame. The clients husband passed away in that accident so please be considerate before saying how lucky she was for not losing an eye.
I don't mean to be cynical. I too think losing an eye to breakage is overblown as it's usually as we say a cracking issue.
***BALONEY***
1.806 chems quite nicely and passes the Z80 drop ball test.
A lot of bad information in this thread :-(
16 hour chem is recommended in crown salt, minimum edge thickness of 1.8 mm, center at 2.2 mm
A good quality A/R takes care of "some" of the chromatic abberation this glass is susceptible to, stay away from Mag/Flor coatings for sure.
There is a significant difference between the SFL-6 (light, titanium-based) and the SF-6 (lead) glass. The SF-6 leaded glass is soft, prone to sleeks (light scratches), and stains quite easily, it cannot be hardened to meet Z-87, but it can be case hardened to meet Z-80 with a special cycle.
There are no acceptable high index glass types that can be used for glass blowing.
Thanks for the input Mike.
Curious- What AR if not magnesium fluoride?
What, if any, other glass types should be avoided?
I've always considered Mag/Flor to be the cheapest available A/R coating. There are plenty of good to excellent A/R coatings available, there's a company in Chicago that coats a ton of glass, and they've got a two-sided A/R that they use that is awesome on high index glass.
I'm not sure what you mean by "other glass types should be avoided".
"A lot of bad information in this thread"
Maybe...
B
Yes, Mike. I worded the glass blowing point poorly. You're right. Meant to say there is a need for glass lenses for glass blowers - not that they are hi-index glass. My fault.
You answered the question with the first sentence.
But if I am remembering right, beside the 1/4 wave thickness for light attentuation with single layer MagFl, I think the index of 1.8 makes it ideal for the amplitude of the reflection to be as low as possible.
B
Barry, perhaps, but a multi-layer looks cosmetically better, and seems to perform better.
We used to do a lot of 1.8 and we had better results with customer satisfaction using a multi-layer coating.
Oh, I agree multi is the way to go. Just sayin'....
B
as far back as 1965 when I started with B@L, we used 1.8 glass every day, apx 1.5 mm ct, not treated as in those days it did not have to be, do not remember having that much trouble with it, certainly not as much as some of you on the board allude to having. It is actually a good niche product, follow mike aurelis advice, on how to treat it, and stop worrying about j.j. schwartz and company LLC
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