Tinting problems " Specks of paint"

[dirceu]

Good morning to all,

we are coming across some major Problems during our Tinting process. The lenses end out with White stains.
We have performed several tests from: Tinting powder, machine temperature, Benzyl alcohol, with no success.

Does anyone have this Problem?
All Information will be grateful

Regards

[Lensman11]

The problem is caused by surface tension in the hard curing process. If it is occasional you can lightly buff the spots with red rouge and they will tint. If it is systemic you must find the issue with your curing process.

[dirceu]

Lensman11,

the lenses are all uncoated! This happens before the curing process.

[Lensman11]

Does this happen with all materials. I would would take several lenses and place them in the same oven you cure your hard coat for about 30 minutes before tinting.

[dirceu]

yes it happens more or less with all materials. We do not work wih Polycarbonate or Trivex. It is strage because our main Company has the same process as we have and they do not have this issue.

[Lensman11]

First try the oven. Make sure you are using a lens prep before you dye the lenses this allows even dye penetration. I would also buff the spots that don’t dye using red rouge or lens polish.

[dirceu]

Lensman11

I sent you a private message.

[lensmanmd]

What water are you using? Distilled, RO, tap? Sounds like hard water contamination is contributing to this since the lenses are uncoated and your partner facility is not experiencing this issue.

[King of the Lab]

Check the tint mixture again or bottom of the vat. Sometimes after a while the dye will cake around the edges of the bottom the vat. Usually this happens when the tint mixture is old or too hot.

What happens is flakes of this hardened mixture fall off the side of the vat and onto the lens. After you pull the lens out of the tinting vat, after rinsed off, the clump just falls off the lens leaving a white spot. Used to happen to me all the time.

Not saying this is exactly what is going on, just taking a stab at it.

[dirceu]

We have checked all possibilities regarding the water Quality. The Quality is good. We are using distilled water.

[dirceu]

Hi King of the Lab,

thanks for the feedback. I have bought new tint mixture, and i will start from the begining all tests.
I´ll get back with the Outcome.

[Don Gilman]

Hi King of the Lab,

thanks for the feedback. I have bought new tint mixture, and i will start from the begining all tests.
I´ll get back with the Outcome.

And make sure your pans are clean. Use a course sponge to remove all residue, no bleach as that can pit stainless steel.

[Mauro.Airoldi]

the diagnostic procedure I suggest is the following:
the problem appears only on the CR39 a or even on the high yes / no indices
the problem appears only on lenses not hardened yes / no
If they are not hardened lenses, try washing them with Acetone to make sure they are cleansed from fat. resolves yes / no
If they are slow, do not harden, try putting them in an oven at 100-110 ° C for 30 minutes and then try coloring them. resolves yes / no
Check the color temperature, it should not vary more than 88-95 ° C resolves yes / no
If the lenses have a very bad wettability (high suficficial tension), micro-bubbles form when the lenses are immersed (especially if you have just added fresh water and therefore rich in gas). start to immerse them and move the lenses up and down to prevent bubbles. resolves yes / no
can you send a photo with the defects? use a backlight with satin glass.
let me know
Mauro

[dirceu]

Hi Don Gilman,

done so! THX for the Tips

[dirceu]

Hi Mauro,

thanks for all the Tips. I will upload some photos for everyone to see.

Attached you are able to have an ideia of the Problems.