Cracks in Coating (Not Scratches at All) Poly only

[Speed]

Suddenly we are having trouble with cracks in the hard coating, poly only. First we thought they were deep scratches. Closer examination we see they are cracks. Anyone else? Solutions? Suggestions?

[Chris Ryser]

Suddenly we are having trouble with cracks in the hard coating, poly only. First we thought they were deep scratches. Closer examination we see they are cracks. Anyone else? Solutions? Suggestions?

Poly is a very soft material. The protective hard coat is a harder material and the AR coating is the hardest of all of them because it is made with SIO2 which is glass.

So most probably the lenses have been subject to some pressure due to cold, or movement and these different layers did not move along with the lens surface and cracked.

[Dr. Bill Stacy]

Heat can do it if they also have a cheap AR coating. I've learned to remove the lenses when adjusting the frame with heat if the AR brand is unknown or suspect.

[pezfaerie]

If they are hapening in the poly hard coat and not an AR coat on the poly my guess would be heat. Either at insertion after edging or someone adjusting the frame and using the frame warmer too long with the lenses in the frame. That or the lab you are ordering them from is having issues with their hard coating process.

[Paul Smith LDO]

Suddenly we are having trouble with cracks in the hard coating, poly only. First we thought they were deep scratches. Closer examination we see they are cracks. Anyone else? Solutions? Suggestions?

Too much pressure during edging, heat, stress; lens BC doesn't coincide with frame BC, warpage; cut too big for the frame, foundation coating, bad lenses, and we can go on and on. Question is too vague to pin point.

[Chris Ryser]

Heat can do it if they also have a cheap AR coating. I've learned to remove the lenses when adjusting the frame with heat if the AR brand is unknown or suspect.

Cheap or expensive coating, they all have the same basic main ingredient, SIO2 which is glass which does not expand under heat as does the plastic.

[Paul Smith LDO]

Cheap or expensive coating, they all have the same basic main ingredient, SIO2 which is glass which does not expand under heat as does the plastic.

Following your logic, all chocolate chip cookies are the same. They all have flour, egg, fat(butter, shortening, margarine), salt, raising agent, chocolate chips. Same basic ingredients, however, not all chocolate chip cookies are the same. They fall into three basic categories: delicious, OK, and inedible.

[Chris Ryser]

Following your logic, all chocolate chip cookies are the same. They all have flour, egg, fat(butter, shortening, margarine), salt, raising agent, chocolate chips. Same basic ingredients, however, not all chocolate chip cookies are the same. They fall into three basic categories: delicious, OK, and inedible.

Actually the basic ingredient of cookies is the flour and depending the additives you put in they become different cookies.

The flour in AR coatings is the layer of SIO2 according to what I Learned, and the additives are different oxides to make it better cookies to you.

[Paul Smith LDO]

Chris, we're talking chocolate chip cookies, a very specific cookie. Not all AR's or cookies are the same. Now dip that in your glass of milk.

[braheem24]

Speaking of Dip, Is it?

[smallworld]

Instead of hi-jacking the original thread, maybe someone could start a "Cookie Recipe" thread?

[Paul Smith LDO]

Instead of hi-jacking the original thread, maybe someone could start a "Cookie Recipe" thread?

If you want my grandma's oatmeal recipe PM me, she calls for polycarbonate but I substitute for Trivex don't use AR as heat will cause the cookies to craze. Normally I would recommend a good beer for dipping but the coarse of the thread would have me substitute the cookies for more beer. PM me for my grandpa's beer recipe.

[Uncle Fester]

Speaking of Dip, Is it?

Ironically it's made of turpentine, acetone and benzine.

[scriptfiller]

Is this happening on all poly or just lab processed poly and not stock poly lenses? If these are coming from lab processed poly it may be a bad batch of coating. $0.02.

[Chris Ryser]

Here are most of the ingredients of many coating recipes:

Re:Sputtering Targets to Chemical Nano TechnologyTo


l High Purity Metals(W 99.9999%, Mo99.99%, Ta 99.995%, Nb 99.99%, Ti99.999%, Zr 99.95%,Ni99.999% Cu99.9999%,Al99.9999%etc.)

l Pure Metals (W, Mo, Ta, Nb, Ti, Zr, Hf, Ni, Al, Co, Cu etc.)

l Alloys (Mo-Nb, Mo-Ta, Al-Nb, Ti-Al, Si-Al, Al-Cr, Ti-Nb, Nb-Zr, Ni-Cu, Ni-Cr, Ni-V, etc.)

l Ceramic (SiO2, Al2O3, Nb2Ox, Ta2O5, WO3, VO2, V2O5, TiO2，Ti3O5, MoS2, ZrO2, HfO2, ZnO, AZO, ITO, etc.)

[Francois Chemoptic]

First of all, please check if these cracks are on both sides or only on one side, and in that case, which one...