Defect varnish

[Etienne]

Dear ,

some few month, we have a random problem with the coating. We have a small ring on the few lens. It's not a classic "point" with a particule on the center but a distortion varnish. We have this problem on CR39, Rx or Stock lenses, 1.6 and 1.67... I use a same varnish for all material
Sometime front or back

We have changed the pipe DI Water, try to changed the power and time IR in the machin... We see the problem at the machin outlet before the finally oven.
We have same problem with 2 tank varnish, same if the varnish is new.

This defect disappears when I remove the lacquer so it's not in the material.

I have try with a new Mix + Méthanol . I have a old Mix alcool (2015) but same problem with the mix product 2016...

I feel that we are putting lot of Mix+Methanol for to compensated the evaporation but the tank Mix+Methanol is not hermetic
Varnish have 1 month and 10° in the tank

I don't see a bubble in the varnish.

Next month, I will try with my other tank. This tank have clean with detergent , normaly I clean the tank and pipe with the flow Méthanol many time.

I take all idea

Regard