Meredith Lens soiled...

[Meatball]

So it turns out that lit fuses tend to emit large, hot bits of smoking matter...

I was lighting some fireworks and I must've gotten my LOC too close to the burning fuses because I noticed that my Jayrob Meredith lens (coated for red) has huge black chunks of matter stuck onto it. I can see them on the wall when the dot is unfocused, and I can even see them when I peer through the lens itself.

I emailed Jayrob about it a while ago because I thought he might know the safest way to clean it off. He referred me back to some threads here about lens cleaning. However I've found that the threads here aren't very "clear" (unintended) about the proper way to clean a coated lens without damaging it. I've read that Windex works, water, alcohol, blow dusters, cotton swabs.... are all the way to go. Which should I do? Do they all work? I suppose I have only one way of knowing for sure but I risk ruining the coating.

This lens has been a great lens, and I'd hate to lose it. What can I do to get rid of the grime?

-Tyler

 

[ZheolD]

i have read those Said threads thay are very stright forward.

Use a Qtip Isopropyl Alcohol then (i have not tryed this next part my self) wrap another Qtip in Teflon tape and Wipe the lens agian After its dryed this is Said to remove water spots and the fibers left by the qtip

hope this helps

Cheers
Josh

 

[Meatball]

True, they are straight forward however I don't want to destroy the AR coating.. rubbing alcohol may end up destroying the coating.... as I've read. :/ What about camera lens cleaner's?

 

[jayrob]

Edit:

Hey before you 'wipe' it, just take the assembly apart and let the lens sit in alcohol for a few minutes...

I'm no expert lens cleaner, but I don't think you could hurt it by doing that. The stuff may just come off really easy with a fine micro fiber cloth after it is soaked.

Like I said, I'm no expert on cleaning, but it just seems like a common sense thing to try first. Here's a picture of how it is assembled: (except the Meredith mods have an aluminum spacer/retainer instead of a brass one)

Obviously, if gun power got on there while 'burning', it may have already damaged some of the coating...

 

[f22warzone]

You wont take off the coating with alcohol unless its a really bad coating
Cleaning coated optics - Photonlexicon
read their .... avoid water at all cost as it will stay stuck to the lenses and all of its impurities.

 

[jayrob]

I'm going to edit my post then... :thanks:

 

[Eudaimonium]

I agree about water leftovers on the lens...
However I do not see why would distilled water be a problem.

 

[HIMNL9]

Well, if you don't use acids, and the lens is made in glass (NOT acrylic ones), then alcohol or solvents does not damage the AR coatings ..... they are usually made depositing metals for evaporation inn a vacuum chamber .....

I left (or better said, i forgot ) a glass AR coated lens from a green module in acetone for 3 weeks, and the AR coating is still there and working .....

The only problem can be, if the lens or the holder is glued, they can melt the glue .....

 

[Helmholtz Watson]

Soaking it for a lil' while is probably a good idea as if there is any grit on there when you rub it it will abrade the lens coating pretty badly. I imagine most lens cleaning guides only really relate to dust and condensed vapors whereas you have chunks of dirty carbon.

 

[Meatball]

Here's a mediocre photo of what I'm up against..

I went to the local camera doctor, and he showed me the lens under a microscope. I saw that I already had a couple scratches on it. And then a lot of gunk to clean off. He recommended I try to clean it first, and then check the results. He sold me some lens cleaner solution. He said, that it's the best stuff anyone can use on a coated lens. It leaves both soft coatings and hard coatings alone. He showed me how to clean properly apply it.

I'm supposed to take 100% cotton swabs, and spray some of the solution on the swabs so they are moderately damp. I'm then supposed to gently press the swab onto the lens and then pick it back up again. I'm supposed to use a fresh swab for every application, so he said I'll be burning about 9 or 10 swabs, but It should work well. He said make sure not to swish, or move any of the contaminants around so I don't scratch the lens.

I'm going to give it a shot sometime soon, and let you all know how this goes. But just in case...

How many lens assemblies do you have left Jayrob?

 

[jayrob]

How many lens assemblies do you have left Jayrob?

I've got my 405-G-1 glass lenses available, and re-stock as needed...

Also, I will soon have a 650-G-1 glass lens mod that is the same power and beam profile as the discontinued Meredith (optimized for red) lenses. It should be just a couple of weeks for those.

Edit:

My 650-G-1 glass lens modification is here how!

Check it out:
http://laserpointerforums.com/f64/f...modification-fit-aixiz-25-increase-46332.html

 

[Meatball]

Alright Thanks Jayrob, I'll be keeping those in mind!

 

[roddenberry]

One thing to remember is that if you try using isopropyl alcohol, use the 99% one and not the standard 70% alcohol-30% water version... that 30% of water might leave a film or tiny droplets on the coating that might be hard to clean up afterwards.

I haven't been able to find the MSDS sheet for the Purosol lens cleaner above... I have to admit that I don't trust any product if I don't know what's in it...

But I think the chemical reaction of the sulfur and nitrates in the black powder might have affected the coating, it may have permanent uncoated "dots" on it.

Robert

Robert

 

[Meatball]

I will keep that in mind...

I will be making an attempt at cleaning it tonight, using that water- based solution the camera doctor gave me. If things aren't looking nice and round on my dot again, I'll be saving up for a new lens.

It's because I'm afraid you're right... if the soot was still hot, then the coating is already damaged!

 

[Eudaimonium]

Pardon me for asking but I can see two reasons for not giving a damn if a coating is damaged that way:
First, it is on outer side of the lens, not on the side facing the diode
Second, if it is damaged, and not strached, how will you tell that? The dot will appear normal. Difference is minimal.

And I see no reason to buy new lens. (BTW sorry Jay, you know what I meant right?)

 

[jayrob]

(BTW sorry Jay, you know what I meant right?)

Yep...

I have a 'chipped' 405-G-1 glass lens in one of my personal lasers (just a very small crack on the outer edge of the crown) that doesn't affect the output power or beam profile in any way.

But since it has this small crack in it, I still can't sell it, even though it performs the same as a perfect one...