Rehabbing a Black Lens?

[Keith Winter]

My engraver forgot to turn on air assist for a job, the entire lens turned black. We tried to clean it with the regular solution and also with some acetone. Acetone got off some of the black in the center but a ring of black remains. I'm a bit hesitant to soak it in the acetone beyond a few seconds in fear of the lens coating coming off, has anyone tried soaking a lens in acetone to remove black spots? Any other methods that work to remove black spots?

See photo of the black on the lens below:
20151109_151322.jpg

[Rich Harman]

I have soaked a lens in acetone before with no noticeable ill affects. With the lens submerged I have even scrubbed it with a Q-tip to get off stubborn stains.

[Gary Hair]

You know that stuff you have with your eggs in the morning? Your lens is basically the same - TOAST...

Call on your (new) friends as II-VI (two-six), they will set you up with a brand-new lens.

[Ron Gosnell]

It looks like you have nothing to lose at this point.
Soak it hope for the best, maybe you will discover a fix for the rest of us when we
forget to turn on the air.

Gozzie

[Mike Null]

Toasted or fried--take your pick.

[Keith Winter]

You know that stuff you have with your eggs in the morning? Your lens is basically the same - TOAST...

Call on your (new) friends as II-VI (two-six), they will set you up with a brand-new lens.

Haha! Yeah wasn't funny when it happened though, between this, a lens not getting tight enough and flying out a couple weeks ago, plus one Trotec original that came unglued and fell out and chipped while they were cleaning it, I'm down 3 lens in one month. Funny we've gone 3 years without ruining any and then last month lighting struck. Gonna try soaking it in acetone and see what happens... If I just go as is, think it might work since the middle is clear or will it just Crack if we try to use it as is?

[Bert Kemp]

thats why my air, water and exhaust are all on one UPS I can't for get to turn it on.

[Jack Clague]

Keith hope you don't mind me butting in here with another lens related question, I have got a very small and faint scratch on my lens, if I am not noticing any effect on the engraving and cutting quality of the beam should I leave it as is or would you try and remove the scratch in some way?

[Rich Harman]

...if I am not noticing any effect on the engraving and cutting quality of the beam should I leave it as is or would you try and remove the scratch in some way?

If it aint broke...

If you don't have a spare, then I would recommend getting one, I would not attempt to remove the scratch. It could be you would notice a difference when you put a new lens in. When I first got my laser I treated my lenses extremely carefully. Now, not so much. My abused* lenses work just as well as brand new ones. Or at least there is not enough of a difference that I have to change my settings.

* By "abused" I mean cleaning them aggressively - but I'm still reasonably careful about it.

[Keith Winter]

Keith hope you don't mind me butting in here with another lens related question, I have got a very small and faint scratch on my lens, if I am not noticing any effect on the engraving and cutting quality of the beam should I leave it as is or would you try and remove the scratch in some way?

Faint scratch should be no issue

[Jack Clague]

Faint scratch should be no issue

Thanks guys, I'm pretty vigilante with my cleaning but i think it was caused by a newbie mistake of not having enough cleaning liquid on my lens or lint free paper, i'll see if I can get a pic so you can see it.

Would love a spare lens but at $420 a pop here in AU its a tight expense

[Dave Sheldrake]

Would love a spare lens but at $420 a pop here in AU its a tight expense

(coughs a lung) HOW MUCH!!

Hummm drop me a directline Jack, I may be able to help on that one with an AU buddy called Stuart

Keith.....no...just noooooo

If you remove the AR coating by mistake backscatter can in theory damage your optical train (as well as launching specular reflections off into the scenery)(usually towards something expensive)

[Keith Colson]

I see they have "HQ" lens on ebay for about 50 bucks. I need to buy one and try it out. The $20 mirror from I got from ebay works fine. Its a pretty cheap experiment. The OEM stuff is ridiculously priced. My Universal lens which is looking aged after 4 years of running is about double the price you quoted. I will order one soon and try it.

[Jiten Patel]

There is a post on here about that very issue I had quite a while ago (can't find it sorry). You can get it off with a lot of scrubbing (delicate scrubbing). Took me a few hours, but managed to get it all off with no visible damage. I just used the Trotec solution and cleaning tissues.

[Jiten Patel]

here you go - http://www.sawmillcreek.org/showthre...y-lens-already