The green in my beam is not the fault of the FC40 it would seem.
Does anyone know where I might find a lens with green AR coating for a convoy L6? I asked Simon about his listing on Aliexpress “Ar-coated glass lens for L6 ,4X18A,L8”. He said the lenses for the L6 and 4x18a are red (probably means purple). I have asked him if he knows where I can find one with green coating, but I decided to ask here too in case someone knows something.
Thanks!
I could cnc grind a 3x21D window down to size, if that one has the green AR.
You could always just take the coating off and go no AR
By what means?
I wonder if the difference in CCT/DUV between the two colors of AR coating is worth the light loss in going with no AR coating at all? It seems like people that have measured the difference report it as being a very small difference. IDK… I an just asking.
I suggest some minus green.
Whatever works. Eye glasses come with AR coatings most of the time, they often need to be replaced before the lens’ do, so there’s a few different products and techniques for it depending on how good the coating is and the type of glass or polycarbonate. I accidentally took the coating off a pair of my glasses with isopropyl alcohol so thats probably a good place to start.
Opticians might have AR remover if you ask nicely but it’s expensive stuff so maybe not. I’ve heard heat gun, boiling water, strong acids, all kinds of solvents. I know I’ve seen posts on here about taking off AR too. Beck when they were all pink. I remember somebody had a good method iirc
The process of MgF2 removal will involve either a mechanical or chemical method or a combination of both. The mechanical method requires an ultra fine abrasive such as .5 micron diamond lapping paste. The chemical method involves strong acids.
Simon sells green AR coated ones.
Edit: I think it has the same lens with 4x18A and he has them listed as green AR.
I’ve been able to remove the purple AR coating on mine with a fingernail polisher (one of those foam strips with multiple levels of fineness), commonly found at supermarkets/pharmacies. The intermediate levels can scratch the AR right off without scratching the glass.
While the difference between purple and no AR is huge, there is no discernible difference between no AR and green AR. Was underwhelmed by my green AR lenses.
In term of light transmission or tint ? Because increased light transmission is the point of AR coating, ideally tint is unchanged, and here the ”green” AR used by Convoy is much better than the commom ”purple” as it affects much less the tint and the little change that it does is towards magenta which is preferable than green.
Thanks for the clarifying question–I meant tint. Even in side-to-side comparisons I don’t really notice a difference in tint between green and no AR, while purple AR makes the center of the beam significantly greener. I don’t have the equipment to measure transmission with accuracy within the difference AR makes.
I tried removing the Magenta AR Coating from a S2+ lens with 99+% Isopropyl Alcohol, unfortunately it didn’t remove the Coating.
Any compound that is used to achieve a mirror polish should make quick work of any optical coating.
UPDATE: For anyone following, Simon’s answer was, “If you need L6 lenses with green coating you can leave me a note after placing an order.”
So I guess I will be doing that. Time to pick out another Convoy light to make this order worth it 
It’s not going to take it right off easy peasy. It took a year or two of scrubbing my glasses with iso almost every day to start to take the coating off my glasses. There’s a good chance it wasn’t even the iso, maybe it was just the scrubbing. Or maybe I got some brake cleaner and/or acid on them a few times. It’s definitely possible. I use a lot of brake cleaner and also a lot of rust remover. Who knows. But they do say not to clean AR lenses with iso. Must be something to it.
I’ve used steel wool for removing the AR coating.