We have quite a bit of issue with tinting polycarbonate tintable lenses from VSP Unity. A lot of them just simply don't take any tint. Some others take the tint but not as dark as if they were tinted by VSP lab.
Anyone knows how to overcome this issue? Thanks in advance.
What kind of tint / system are you using?
It's an old dye heating system. I'm not at the store today, but can get the machine's make and model on Monday if you need it. Thanks
Are you using "old dye" also? If you don't have the kind of dye that is able to penetrate the hard coats on poly/high index you are just waiting for the heat and chemicals to tear the hard coat off and tint the material beneath. If so you are about to see a wave of customers returning with peeling sunglasses, be prepared. Don't use tints approved for CR-39 only on these types of lenses.
I'll check with the lab technician about the dye. Thanks
Originally Posted by newglasses
A conventional tinting unit is nothing else than a basicrestaurant food warmer consisting of a heating unit with a thermostat, a heattransfer media (which can be water or a heat transfer oil, and stainless steelbuckets which hang on horizontal steel bars.
( see ----------> http://www.missionrs.com/countertop-food-warmers.html)
In order to tint properly the lens surface has to open its pores and the colorpigments have to penetrate into the lens surface. Polycarbonate lenses have nopores on their surface, and only the anti-scratch coating, if tint able willcontain the necessary pores to let the lens getting tinted.
Non tint able Poly's have no pores in their coatings, andtherefore will not tint.
Probably you are probably using Rx lenses from VSP and some cheaper stock lenses that are non tintable.
In general Poly and high index lenses are harder to tintas the temperature is kept low due to the early dye decomposition when heatedtoo high.
There are now high temperature Rx dyes available from AmconLabs that will let you crank up the temperature to way over the boiling point,without early decomposition.
You can also look into the Micro Tint system where youactually tint in a Micro wave unit and can reach very dark tints in 4 to 8minutes on Poly and high index.
see --------------> http://optochemicals.com/micro_shortdescript.htm
Don't spend too much time fixing your "tint", if VSP is sending you improperly coated lenses, you can never overcome the HC they put on. Guess, they are coating the lenses contrary to your instructions with a un-tintable HC. The way you check is to order a tintable stock poly lens from another supplier. If that tints, the problem is with VSP, not you.
There are some new pre-tinted products (PermaTINT) available that offer consistent dark colors on polycarbonate without the hassle of tinting. http://www.visdynlab.com/page/polycarbonate
tintable poly? they lie.
No they don't!
The worst HC=better tintability!
I have tested 12 poly lenses for their tintability, all of them the same brand but at least six of them had variations adopting the same tint i color and density.
It turned out the manufacturer had 4 different manufacturing plants across the Globe and mixed the lenses and put them into same enevelopes.
somo is a good tintable stk poly lens. using them for years with no troubles.
Trivex is the way to go !
Does stock Trivex tints?
There are Manufacturers that produce tintable coating trivex lenses
I honestly have never tinted trivexI heard it works well but the blanks/stock lenses are too expensive for me to fool around with, whats the story guys? Any tips?
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