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Thread: Cleaning coated optics

  1. #11
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    Quote Originally Posted by mixedgas View Post
    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. ... Drop and drag takes practice and good chems, but its worth learning
    This. I've gained a little too much experience with cleaning optics since I started doing undergrad research in AMO at OSU and got an actual, paid job doing it for the summer. Avoid using acetone unless you can't get whatever is on the lens off using just the methanol (like when mirrors were mounted with double sided sticky tape), and be sure to drop and drag with methanol afte using acetone. And if you get any fingerprints on a lens at all, clean it right away (I did that once early on in my research, and I had gloves on so I don't know how it was a fingerprint, but I still felt bad). Getting water on optics sucks big time as well, we had our water cooling supply explode recently. Good luck with maintaining everything!

  2. #12
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    Apr 2009
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    Digging up an older thread here, but i ran across this on another page. thought i would share:

    Quote: anorton wrote:
    "Don Stauffer" <stauffer at (no spam) usfamily.net> wrote in message
    news:4ac4b67c$0$89384$815e3792 at (no spam) news.qwest.net...
    Kyle wrote:
    Would anyone happen to know of any good guides for cleaning optics in
    a research laboratory setting? Our group uses alcohol pads but I find
    these to be very unsatisfactory because of the residue they leave. I
    have used methanol and the "drag" method with lens tissue in the past,
    but don't have access to methanol currently. Is acetone a suitable
    organic solvent that doesn't streak? Thanks.

    Kyle

    I would NOT use acetone on any coated lens. Our techs always used
    isopropyl if there were no instructions on specific cleaning methods. I
    don't think we had any coatings that were water soluble.

    While iso is okay on most coated glass optics, apparently alcohols do
    damage LCD screens. Advice seems to be use de-ionized water and very
    mild soap.
    Why do you advise against acetone on any coated lens?
    I guess I should have restricted it to any unknown coating. If the
    instructions for that coating say to use acetone, okay. However, I have
    seen coatings damaged by acetone and similar solvents.



    What kind of coatings have you seen damaged by acetone but not alcohol?

    True, acetone and other solvents can damaged plastic substrates, epoxy
    replicated optics and the occasional organic thin film, but I have never
    seen acetone harm an inorganic thinfilm coating on glass. I am asking
    because this is one of those pieces of optical cleaning superstition I have
    heard before but have never seen any direct evidence of in 30+ years of
    working with optics. What I HAVE seen are coatings that are so delicate or
    porous that ANY cleaning or wiping damages them, but then people attribute
    the damage to the particular technique or solvent they happened to have
    used.
    --
    Adam Norton

    Norton Engineered Optics
    www.nortonoptics.com

    (Remove antispam feature before replying)Back to top matt...Posted: Sat Oct 03, 2009 9:24 amGuest I just thought I would throw in my $0.02 worth, based on some decades
    of professional experience in both plastics machining and optical
    metrology equipment manufacturing --

    IPA is a useful solvent for general cleaning purposes. It does not
    "instantly craze" acrylic material in general, BUT it will instantly
    cause crazing on highly-stressed acrylic material, such as parts that
    have been machined badly or extensively, and on molded acrylic parts
    such as lenses. It is highly dependent on how much heat has been
    introduced into the part during the processes, and crazing can occur
    as a process over time as well based on the stress level in the
    plastic.
    Methanol is by far the best solvent for bench cleaning, especially
    where lens tissues and drag/wipe technique can be employed. Its high
    evaporation rate is a big benefit as compared to IPA. It can be used
    effectively as well with standard cotton swabs or with the more
    sophisticated cleanroom-type swabs like the Texwipe Absorbond line or
    other similar stuff. Spotty residue is generally solved with fresh
    solvent (no absorbed water), and as noted earlier, not outrunning the
    evaporation process.
    Acetone is also useful for resistant oil-type contamination. I have
    used 50/50 mixes af acetone/methanol in some cases. Acetone is a
    complete no-no on plastic optics, as is methanol. Additionally, be
    cautious around cemented doublets or any other cemented optics with
    either methanol or especially acetone. The cement can be attacked if
    the exposure to these solvents is significant.
    I agree with the previous poster about inorganic thin-film coatings
    not being sensitive to most common solvents. I have seen cautions
    against cleaning with or without solvents on printed literature
    supplied with things such as narrow bandwidth filters, made by
    companies like Omega and others. I believe this is also simply an
    indication that the films are extremely delicate, and any touch is a
    risk.
    Keep your solvents fresh. The solvents under discussion are extremely
    hygroscopic, and I have found it best to buy the best possible grade,
    such as HPLC grade, in small sealed containers like 500ml or 1 liter,
    put small amounts in use dispensers, and dispose of it when it gives
    bad results after a few days of atmospheric exposure. Keep the main
    stock sealed as much as possible.
    Final notes: Always blow the dust off before wiping. Little spots of
    water-soluble contaminants, like spit or coffee spray, will never come
    off with alcohols. Always try water as a last resort when a "non-
    cleanable" spot gives you problems.

  3. #13
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    Quote Originally Posted by mixedgas View Post
    .

    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.

    Steve
    I tryed to clean some Laserwave mirrors with a Commerial availeble binocular cleaner.

    After the cleanjob mirror was black/blue and I could trow the mirrors away.

  4. #14
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    Maybe we could do a group buy for bulk methanol and some glass bottles with teflon stoppers. That should be enough to last a bunch of PL members a lifetime. I imagine the shipping would be the most expensive part. According to this website....
    https://www.spectrumchemical.com/OA_...240&isSupply=0
    We could do:

    16 - 250ml bottles @ $6.00 (4L bottle purchase)

    or

    40 - 500ml bottles @ $6.00 (20L drum purchase)

    The only other expense would be the bottles, roughly $4 a piece for clean glass boston round bottles with teflon lined caps. And of course shipping. I'd imagine $10 for ORM-D via UPS in the US.

    Is $20 for 500ml of reagent grade methanol worth it?

  5. #15
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    I'd buy one or two..

  6. #16
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    Thumbs up

    I'm in for a bottle.

    Maybe we can make a complete package which also includes lens tissues.

  7. #17
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    Quote Originally Posted by mccarrot View Post
    I'm in for a bottle.

    Maybe we can make a complete package which also includes lens tissues.
    Good Idea! Swabs too. Should I setup a group buy? I really think we need to do 40 bottles to do it right.

  8. #18
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    Apr 2009
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    I'm interested in a couple, swabs too

  9. #19
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    If you can supply sealed and reagent grade methanol, I'll buy a couple. Best regards, weartronics

  10. #20
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    I just priced out First Contact, Yikes!

    I'm down for a set (methanol, wipes, swabs) however it works out.
    "TO DO IS TO BE" - Nietzsche
    "TO BE IS TO DO" - Kant
    "DO BE DO BE DO" - Sinatra

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