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Thread: Cleaning coated optics

  1. #1
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    Default Cleaning coated optics

    I'm curious what is recommended for properly cleaning coated optics. Normally I use 91% Isopropyl alcohol and a soft microfiber cloth for lenses and mirrors. I need to clean the dichros in my RGB setup and I don't want to hurt the coatings.. any advice would be great!

  2. #2
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    Rob (Stanwax) sells some wonderful stuff called First Contact that drys to a film that just peals off taking the gunk with it. It can be left on to protect any optics is storage as well.

    Carl

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    first contact as mentioned above
    Eat Sleep Lase Repeat

  4. #4
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    Thanks for your responses. While that is probably the best solution available bar none, I would like to know if there are any options that are a bit more cost effective? I'm on a bit of a budget ATM.

  5. #5
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    try acetone (lab grade) with lint free lens wipes/tissue or electronic grade q-tips they usually have a wooden stick and leave almost no lint behind. Try to keep the wipes/tissue in a zip lock, they will absorb moisture and impurities from the air, and you'll end up with these smudged on your optics. Microfiber cloth is good, but you should use a new piece every time you clean an optic or you'll transfer the dirt from a previous cleaned optic.
    there are a few methods of cleaning i've heard of, when using lint free lens wipes and acetone.
    1. place the optic flat on a wipe (surface you want cleaned face up), then place another wipe on top of the surface you want cleaned. Place a couple of drops of acetone in the middle of the wipe and slowly pull the top wipe across the surface.

    2. Another method. (got it from ISOMET, cleaning procedure of an AOM crystal)
    Fold (4 times) a new lens tissue into a triangle to make a cleaning tool.
    Dip the tip of the lens tissue into fresh acetone or spray fresh acetone from a squeeze bottle onto it. Then shake excess fluid out of the lens tissue. Do not handle the wet area of the tissue, as your finger oil will be absorbed and contaminate the optical surface.
    Wipe (only once) across the surface in an even motion. Do not reuse the tissue!
    Repeat with a new tissue each time and for each surface that needs cleaning.

    I have also used Isopropyl when i could not find acetone, but i try to get 97% or as high an possible.

    Acetone will also absorb moisture from the air, and you will notice a smudge on your optics if this happens.

    I am in no way an expert, but the above suggestions have worked for me.
    Cheers


  6. #6
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    Default Optic cleaning

    This was taught to me by Dale Harder.

    soap and water
    30% hydrogen peroxide dip.
    HPLC grade acetone rinse
    air dry.

    soap and water remove most of it
    h2o2 burns off any organics left
    hplc grade acetone washes away the left over water and drys free of contamination.

  7. #7
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    Thanks! I'm assuming, given the fact that both of the last posts mention acetone, that acetone will not harm coatings?

  8. #8
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    .very high grade acetone for grease, methanol for removing the acetone residue.
    Wood swab with NO glue, and cotton ends, never a chemwipe unless I'm desperate. Kodak's high grade optical tissue line has been bought by someone else, avoid cheap lens tissue because they may have "stones"

    Avoid any water like the plague.

    Soap and H2o2 are last resorts , although drug store h2o2 will clean a ion cavity optic enough to get you lasing in a pinch. Dale does preclean his stuff in h202, but his lab is kept freezing and I've had mixed results in warm, humid, labs. its not optimal for long term use and encourages hydrophobic optics coatings to retain water. H2O2 will take off catsup stains and sweat stains and a few other things that acetone will not (disgusting biomed and bio lab optics, but that is another thread, called, "How do I clean my optic if its been used to probe a monkey's rectum?" (not your fault Kecked, you didnt know...)

    Avoid commecial walmart/drugstore optics cleaning stuff like windex, binocular cleaning stuff, antifog solutions, it often has ammonia in it which frys silver and aluminum coated optics and fogs the canada balsam in beam splitter cubes. Some canned air things with freon eat silvered optics.


    Drug store/hardware store chems go from the factory to the packaging places in disgusting 55 gallon drums that are reused with different chemicals and often have tracers or denaturlants in them that leave white films. Its worth the time to get a decent bottle of acetone and a gas chromatograph, spectroscopic, uhp, or electronic grade methanol, especially if you do intracaity (inside the laser) work.

    I dont have the time to retype it here, but go to sam's laser faq and read my description and that of others, of "drop and drag" cleaning of optics.

    Short of the polymer film method (expensive in the US because of patents/hazmat shipping) and helium plasma cleaning, drop and drag gets you the best there is, provided your NOT in a humid place. If your in a very humid place, its often not worth using acetone at all, especially with coated UV optics.

    Coherent also has drop and drag on their website some place

    Drop and drag takes practice and good chems, but its worth learning

    for those really good 700$ optics, ie laserscope, hene cavity.ion laser cavity do the rense teh swab thing, and never back contaiminate by dipping the swab or tissue in the bottle. I get disgusting some times and just pour the chem over the swab, it depends on what the floor is made of, but then I work on commercial and lab optics stuff where we back fill the solvent bottle with argon or nitrogen to keep the water out. (mandatory in Florida, Panama, Alabama, and Other humid places) Also avoid eye droppers with rubber bulbs, the all teflon droppers work in a pinch.

    Also. with swabs. rinse the swab, swing it around fast at arms length to reduce the acetone on the swab, and roll the swab as you use it across the face of the optic to avoid scratching the optic. It also takes some work to learn the wobbly W technique of going aound the optic in a spirograph pattern with a swab

    there are also folding techniques for clamping lens tissue in hemostats without fingerprints or latex residue on the tissue, but we'll save that for another time.

    Ok I googled it:
    Tiffin bought the Kodak line of tissue, and that stuff rocks, get in the sealed envelopes that have super clean cardboard dividers around the tissue, 4-5$ a pack and a pack will last a long time. unless you were maintaining 6-10 medium frame ion lasers in a university like me, in which case, you order cases.

    If u ask a pharmacist nicely and explain why you need them, they can order you a case of individually wrapped wood swabs in sterile paper envelopes for about 13$ a case. Its a "throat swab" to them, for getting strep throat samples. Gently explain why you need them and find a small independant drug store or medical supplier, and they show up in 1-2 days if not in stock. Go to CVS or Walgreens and ask for this and they look at you like your crazy as its not in their computer and or their repatoire. But a small independent pharmacist who caters to specialty needs will understand and order them in a heartbeat.

    none of this applies to co2 or excimer optics, which are a entirely different breed of coating, and often water sensitive. Also acetone is forbidden on aircraft worldwide by ICAO regs, but 1/2 oz of methanol COULD? go in your toolkit if properly labeled with a commercial label. I have a friend with a framed letter from homeland security who found acetone in his checked tool kit but did not say a word about the bottle of methanol right next to it. Dear sir, you are now a blacklisted disgusting scoundrel who we could flog and imprision and fine you 300,000$, but we are going to be nice and let you off. Dont do it again, even though we trust you to service optics shoved up somebody's colon. We're watching you, thank you and have a nice day, the T_A.

    ELECTROFREAK, this is NOT YOUR FAULT, You needed to know and had the right to ask, so igore this:

    Rant Mode, Please Number One, Engage! ""BUT IF ITS ONE DAMNED THING ON PL AND SAM"S FAQ AND ALT LASERS THAT NEEDS TO BE A STICKY OTHER THEN LASER SAFETY< ITS THIS> I have typed it one too many times over the years!!! ARGH!!!!!!!" end rant mode.

    Steve
    Last edited by mixedgas; 07-14-2009 at 14:02.
    Qui habet Christos, habet Vitam!
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    When I still could have...

  9. #9
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    Um... WOW!!!! That's more than I could have ever hoped for.. I really appreciate you taking the time to type all that. Hopefully Admin will stickify this, since I agree it should be permaposted for all the world to see. And luckily for me I work in a hospital so swabs are no problem at all..

  10. #10
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    I would spend the few bucks on lens tissue.

    I have really high grade methanol, meant for use with laser optics (for metrology and measurement stuff... but its all the same stuff) and tried a little experiment. My HeCd laser makes about 45mW of 442nm. Cleaned one brewster with a q-tip + methanol and the power dropped to like 20mW. Cleaned it again with a lens tissue and it was back at 45mW. Tiny tiny tiny pieces of lint can make a huge difference, especially in low-gain lasers. for what it's worth, the window looked spotless after I used the q-tip, but it obviously wasn't! And these were GOOD q-tips! Autoclaved, sterile, meant for electronics.

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