In-House Scratchguard

[Virginia]

Does anyone have anything (good or bad) about in-house scratchguard coatings?

Baking vs. dipping?

Thanks for input.

[Jeff Trail]

You going to be running alot of poly? or CR39/High index etc. etc. ?

Jeff" didn't I post this once before?" T.

[Virginia]

It would be for CR-39 & Hi-I

[Jackie L]

Virginia,

We use a BPI in-house scratach coat treatment for FT and other surfaced CR39 lenses. When we finish a stock CR39 or HI lens, we depend on the manufacturer of that stock lens to provide the coating. Because we frequently tint or uv coat our customers previous lenses for sun or computer, we need to know that the scratch coating will allow the dye to penetrate the lens. Remember the Quartz Coating of yesteryear? Any other treatments or coating that have been improved? Let us know.

Jackie O

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Still a Maina for now

[Jerry Thornhill]

In House Scratch Coatings;
Basically I believe that in house scratch coatings that are dipped and baked have about the same effect as waving your hand over the lens and saying it is scratch coated.
A few years ago a salesman representing one of these companies called on me and tried to persuade me to use the one he was selling. He was wearing on his lenses and swore it was as good as any factory coating. He took his glasses off and handed them to me so I could see there were no scratches. Unfortunately he was a Hyperope and couldn't see them. I politely told him he should never show that pair of glasses again as they contain more scratches than I had ever seen on any pair of glasses. He stopped selling the coating.
A few years ago Silor published a paper on these coatings. They were very objectionable.
They tested various factory hard coats versus the various dip and bake coatings. The conclusion that they came to was that an untreated CR-39 lens was more resistant to scratches than those treated with after market dips.
As for the old Quartz Coatings my favorite was AO's Permalite. Put it in the dye tank, come back 3 days later and hope you had a Gray 2. They have one now on the 1.60 that is the same way.
The harder the scratch coat the more difficult it is to tint.

Jerry

[This message has been edited by Jerry Thornhill (edited 06-25-2000).]

[Virginia]

What about this "wonderful" stuff adveritised at http://www.optochemicals.com/scratch.htm. One of my wholesalers swears by this stuff. But it may be because they sell it (glorified water if what everyone else says is true) for $60 a quart.
But has anyone out there actually used this stuff?

[Jerry Thornhill]

Virginia,
I did my first reply in a hurry and was going to edit the lousy spelling but you came in to fast. I don't know about that particular coating and I will check out the web-site. A good question to ask if you decide to use it is will your wholesaler or the company stand behind it enough to replace the lenses at no charge to you. I doubt that they will. If they will then they have a great product.

Jerry

Also Steve would be a good person to ask about adhesion of AR with these coatings and whether or not they are removed in the cleaning process for AR.

[This message has been edited by Jerry Thornhill (edited 06-25-2000).]

[Jeff Trail]

Any of these coating are not going to work as well as say a ionized coater or a spin coater.. but then again if you are a optical shop you don't want to drop 15 or twenty grand on a backside coater do you?
Since you are usually (retail) selling an insurance policy more then just a lens thats coated you can do it a couple of ways... you can get just about EVERY lens design and material out there that comes with a "factory" hard coat.. of course if its a lens thats being ground then it will end up with only a front side coating , unless you do get a back side coater.. so what to do? Me? I usually just recomend my accounts just use the UV/Scratch coat combination for the dye tanks.. your giving them a little of both :) BUT more or less selling them that replacement policy....
First thing is that the only real GOOD coatings are a real pain in the butt to begin with because you can't tint the lens! :) .. from there on out it's more or less just a "catch" phrase... Take that big "mess" the Diamonex..did you ever see that lens? .. Monsanto lost their *** on that one :0 .. all it amounted to was a water white poly (which ya coulda got anywhere) with that ultra hard coat.. it was an amazing coating but you couldn't tint it.. and it was expensive as all get out...
If you are a wholesaler then get you a good backside coater or a spin coater.. if you are retial then just get the UV/Scratch combination and be done with it.. they'll get a little of both but not as good a coating.. they should never have called it "scratch coating" to begin with in my opinion people in general think "oh it has "scratch" coating.. well then I can clean it with any ole thing and it will be fine..sand paper..no problem".. :)..
Well thats my pennies worth of contribution......

Jeff " STOP using those shirt tails to clean your glasses" T.

[Texas Ranger]

The issue of scratch guarding appears, and always has been, an issue of lens durability that was a big deal back when everyone was wearing crown glass. Even glass scratches! These ar glasses people, they all scratch when something harder and rougher hits up against them. The only lenses we warranty against scratching are TD2/Crizal lenses, and that's warranted by Essilor labs. We don't warranty glass, factory scratch coats, etc. We certainly don't sell some eyewash SRC. Actually, people know when they're abusive with their specs, but expecting the optician to replace them is generally absurd. Be up-front with them, the in-house hard coats aren't going to stop scratching, they just promote negligence, and remakes and a further view of ophthalmic lenses as cheap, and cheap to replace. Al.

[Jim G]

You folks bring up a number of good issues. First, ALL poly, 1.6, 1.66 and finished mid-index will come with both a front and back SRC. Surfaced mid-index may or may not come from your lab with a backside SRC. We test all lenses for scratch resistance; if it is less than uncoated CR-39, we automatically add a backside SRC. Our experience is that, with the exception of Spectralite, all current mid-index lenses are much less scratch resistant than uncoated CR-39.

That leaves CR-39. I would recommend a simple test. Ask for a sample of the coated lens from whomever is selling the in-office dip stuff and compare it to a factory hard coated lens (while not scientific, a little piece of steel wool works quite well for comparison). I think you'll find that the Essilor testing noted above to be correct...in-office coatings add little or nothing to the scratch resistance of a CR-39 lens. Some of these do contain a silicone derivitive (makes 'em slippery) which is a definite NO-NO if AR coating as well. A good SRC will actually enhance the SRC of the ARC!

Of significance, most manufacturers (and many wholesalers) will stand behind their SRC lens with a warranty against scratching for at least a year. While not "unscratchable," factory/lab coated lenses are significantly better than uncoated lenses.

Hope this helps.

[Rich R]

As I can tell from all the posts, and the optical labs I've dealt with that use the dip scratch coatings claim they are not up to par, I feel if there was an easier way to apply backside coating that more labs would be using that instead of the spin coater used by most. Rich R