Countrywide specs

29/08/2025

25/08/2025

17/05/2025

1 Optical lenses
Most optical outlets use as a standard lens for run of the mill jobs a material called CR39.
Cr39 came on the market in around 1940. By the time World War 2 began, the plastic revolution was well on its way . Most lenses in those day were glass . But due to safety issues they are being phased out . However there are glass lenses still manufactured for extremely high prescriptions and even diving masks.
New plastics were introduced by a company called Pittsburg plate glass company,and products like pleiglas and Lucite ( both trade names), were thermoplastic materials that were alkyl resin with low pressure thermosetting properties. (Google it).
The subsidy company connected to PPG called Columbia southern chemical company is where the researched for clear resins. The particular resin was alkyl diglycol carbonate (ADC) monomer that PPG trademarked under the materials batch name “CR-39”
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17/05/2025

It’s a new year. At least 1/4 of it’s gone . I’ve had bot cataracts done. 20/20 vision in both eyes. Thanks Dr Francis ( Ballarat).
I’m still doing specs! And if you ever have questions on products feel free to send an email stevemck58@gmail.com
There are a lot of lenses out there some sold with fancy jargon. Sounds good . But what does it mean ! Elite?
And there are different grades of coatings from no coatings ( normally any pair that you haven’t paid for to diamond finishing) The information I’m sharing with you is from my 50 years in the trade . And from companies I still have contact with. I can source anything you want from normal specs to under water and specs for sporting applications. Even if you have broken your own frame , I could fit your lenses into another frame.
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Got a problem with your specs, they don’t work for me?
I broke my frame?