Cleaning optics
Kyle
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
Helmut Wabnig
Lenses with mount or the glass barrels alone?
The best results are with a standard kitchen dishwasher machine
if the glasses can be removed.
w.
Kyle
> On Wed, 30 Sep 2009 11:50:54 -0700 (PDT), Kyle
>
Typically within the mount. I am curious if there are any good guides
in general since this is a task that seems to be limited only to
learning from experienced individuals. Thanks.
Kyle
anorton
"Kyle" <kyle.m....@gmail.com> wrote in message
news:dbfe5a49-c1ed-404b...@c37g2000yqi.googlegroups.com...
I have often thought that there should be a good scientific guide to
cleaning optics, but I do not know of one. There is too much tribal
knowledge and misguided superstition floating around. Some of the big optics
catalogs publish techniques with conflicting advice. One big issue is
whether alcohol should be used for cleaning aluminum-coated mirrors or not
(I have used it in very critical applications with good results).
Here is my tribal knowledge:
Pre-packaged alcohol pads do not work well because they are usually only 70%
alcohol. The droplets and streaks of water left behind as the alcohol
evaporates leave residue.
The secret to the wiping technique is to use a pure solvent (either acetone
or alcohol), and -- most importantly -- wipe no faster than the trailing
edge of the solvent evaporates. If you wipe too fast, you will leave behind
steaks that evaporate and leave residue. Most people find it easier to use
acetone since it evaporates more quickly. With good technique, you can even
use solvent that is not so pure. Make sure your tissue or cloth makes
contact with the surface along a clean straight line with no wrinkles. Apply
light even pressure across the cleaning edge and do not try to clean too
wide an area at once. I like to use the knit polyester cleanroom wipes.
Also, brush off any large particles before wiping.
If you have large, unmounted optics to clean, one of the best techniques is
to wash them (if the coatings and substrate can handle it) in a dilute
neutral detergent solution. Do the final rinse in DI water. Set on edge and
blow dry with clean, dry, compressed air carefully from the top to the
bottom.
If you have small optics that have to be REALLY clean, one option is to use
the First Contact polymer
http://www.photoniccleaning.com/
But it is expensive and takes several minutes to dry.
--
Adam Norton
Norton Engineered Optics
www.nortonoptics.com
(Remove antispam feature before replying)
Frogwatch
wrote:
> "Kyle" <kyle.m.dougl...@gmail.com> wrote in message
I clean optics every day. Here is how I do it. Get Palmolive
dishwashing liquid and dilute it 3 to 1 with water. Use this in your
ultra-sonic bath. Before the ultrasonic bath you might want to squirt
some acetone on the optics if they have nasty residue on them but
otherwise do not use acetone because it ALWAYS leaves residue that
must be cleaned with isopropyl alchohol. After a few minutes in the
ultra-sonic bath, pour distilled water over them. Then, use canned
air to blow all droplets off of them. I use 3M brand air bought by
the case from Wal Mart. If you leave any droplets on the optics, the
droplets will absorb stuff from the air and then leave residue when
they evaporate.
Bob May
used dishwashing detergent and water. I think that it was a site on
antique telescope maintaning. One of the sectrets was to not rub the glass
but rather let the detergent do its work and gently float the dirt off of
the glass with the weight of the wet towel.
--
Bob May
rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net
Kyle
dishwashing detergent as well. It seems that compressed air/solvent
and lens tissue are the only way to clean optics that are in a mount
in a setup. Thanks again everyone.
Kyle
o...@uakron.edu
ultrasound, soon you will not have a laser mirror.
We cover that in Sam's laser FAQ.
Steve
Don Stauffer
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.
DougD
Well, one of the more sensitive things to clean are inter cavity optics on
lasers, the hight and output reflectors, brewster windows, etalons, etc.
The method tought to us that had to go through owners service courses
by Coherent, Spectra Physics was the clean and drag method. Their
manuals and service kits included methanol, however their own techs
and ours used electronic grade acetone. I've never had any bad experience
doing it that way, but you do have to be careful of any parts that might
be affected if you're cleaning optics in the mount. Also, one company
that I worked at was getting their ISO9200(?) rating and as part of the
maintenance of the process lasers, that was also the method that they
approved, however I had nothing to do with how that was figured into
the plan. It may have been that they just did not find anything objectionable
to an existing in house scheme in place and left it alone, not that it was
something that they came up with.
Anyway, it always works well for me!
d.
anorton
"Don Stauffer" <stau...@usfamily.net> wrote in message
news:4ac4b67c$0$89384$815e...@news.qwest.net...
Why do you advise against acetone on any coated lens?
Richard J Kinch
> Then, use canned
> air to blow all droplets off of them. I use 3M brand air bought by
> the case from Wal Mart.
Caution: Canned dusters can easily and permanently ruin a lens coating if
you spit a bit of liquid instead of gas out of the can. Best to hold the
can down on a tabletop and move the lens in front of it than moving the
can.
Walmart dusters are loaded with a high concentration of bitterant. It
seems they all have that now, but the Falcon brand seems to be the least
concentrated. What a nuisance.
Ordinary shop compressed air is always too contaminated for cleaning
optics.
I bought a 30 lb jug of R134a from Sams Club and machined a duster tube for
the Acme fitting. Lifetime duster with no bitterant.
Phil Hobbs
Microfibre cloth does a good job if it's clean. Much better than Q
tips, anyway.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net
Frogwatch
wrote:
Yeah, you do have to be careful about getting the liquid from the
canned air. Maybe I'll try the R134 trick.
BTW, there is a guy who always shows up at Microscopy shows with this
gadget attached to a CO2 cylinder where he uses CO2 snow to clean
optics, kinda interesting.
I'd forgo the acetone unless I needed to dissolve something. Just use
very dilute palmolive followed by distilled water from the grocery
store and then blow the droplets off with canned air.
I make x-ray optics. One day a representative from a govt scientific
agency I will not name called me up desperate to know how we cleaned
our optics. These are s'posed to be THE EXPERTS so I sorta danced
around what cleaner I used not wanting I used something as
unscientific as Palmolive. Finally they kept calling back and I had
to confess it was not some super expensive special x-ray optics
cleaning product but Palmolive from the grocery store.
anorton
>"Frogwatch" <dbo...@mindspring.com> wrote in message
>news:486f9f02-c7da-4b2a...@m38g2000yqd.googlegroups.com...
I have seen the CO2 system also. I think there are a few reasons it is not
more popular. People who clean lots of optics have cheaper and faster
methods (e.g. Palmolive), and people who only clean optics occasionally can
not justify the cost and floor space it occupies. Also, it cools the
surface, so in many cases you have to keep the optic warm on a hot plate to
avoid forming water frost. This also can cause thermal shock issues.
By the way, Palmolive does not sound nearly as "unscientific" as Orvus Horse
Shampoo that was recommended to me many years ago. It does work well for
optics (neutral pH, no scent, no color). It is also used for fine textiles.
Phil Hobbs
> On Oct 1, 6:09 pm, Phil Hobbs <pcdhSpamMeSensel...@electrooptical.net>
> wrote:
>> Kyle wrote:
>>> Thanks for the inputs. I have seen websites suggesting the use of
>>> dishwashing detergent as well. It seems that compressed air/solvent
>>> and lens tissue are the only way to clean optics that are in a mount
>>> in a setup. Thanks again everyone.
>>> Kyle
>> Microfibre cloth does a good job if it's clean. Much better than Q
>> tips, anyway.
>>
>> Cheers
>>
>> Phil Hobbs
>>
> canned air. Maybe I'll try the R134 trick.
> BTW, there is a guy who always shows up at Microscopy shows with this
> gadget attached to a CO2 cylinder where he uses CO2 snow to clean
> optics, kinda interesting.
There's a huge thermal shock with CO2 snow, which can make coatings
craze. You can try it out with a $12 fire extinguisher, but don't use
it on anything you care about.
OTOH liquid CO2 is about the best organic solvent out there, so if the
coatings survive, you certainly don't have any fingerprint oil left on
that surface.
> I'd forgo the acetone unless I needed to dissolve something. Just use
> very dilute palmolive followed by distilled water from the grocery
> store and then blow the droplets off with canned air.
> I make x-ray optics. One day a representative from a govt scientific
> agency I will not name called me up desperate to know how we cleaned
> our optics. These are s'posed to be THE EXPERTS so I sorta danced
> around what cleaner I used not wanting I used something as
> unscientific as Palmolive. Finally they kept calling back and I had
> to confess it was not some super expensive special x-ray optics
> cleaning product but Palmolive from the grocery store.
Fun.
Don Stauffer
instructions for that coating say to use acetone, okay. However, I have
seen coatings damaged by acetone and similar solvents.
Don Stauffer
>
> Yeah, you do have to be careful about getting the liquid from the
> canned air. Maybe I'll try the R134 trick.
Yeah, I remember ruining an important test sample doing that. The
sample was in a vacuum chamber, and we were ready to close the chamber
and start the test. I grabbed a microduster can and wanted to give it
one last blast. I guess I had tilted the can as I reached through the
mounting fixture. A tech saw what I was doing and yelled and reached
for my hand, but too late, a blob of the supercold liquid hit the sample
and instantly cracked the thing! Fortunately we had ordered a spare
sample, but we had to scrub the test while we characterized and mounted
the spare. There went a couple of grand in an instant.
Phil Hobbs
Also plastic lenses can be a problem...IPA crazes acrylic instantly.
Helpful person
<pcdhSpamMeSensel...@electrooptical.net>
>
> Also plastic lenses can be a problem...IPA crazes acrylic instantly.
>
> Cheers
>
> Phil Hobbs
>
Freon used to be one of the best agents to clean plastic lenses en
masse. However, that cannot be used anymore.
Skywise
news:3rCdneC2qpbXO1jX...@supernews.com:
> OTOH liquid CO2 is about the best organic solvent out there, so if the
> coatings survive, you certainly don't have any fingerprint oil left on
> that surface.
If I'm not mistaken, that's what they use on the BIG optics.
Like the 10 meter Keck.
Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
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Sed quis custodiet ipsos Custodes?
anorton
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.
matt
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.
gr
previous blogs have good things to say about the current state of
scratch dig standards.
http://www.laserfocusworld.com/blogs/wk_smart/index.html
gr
David Combs
I got here when the above post was the only one left, so maybe
it's already been answered.
I asked the optician (the guy who "makes" the glasses) at the store where
I buy my eye-glasses how to best clean these "plastic" glasses.
(I *vastly* prefer glass -- can clean with dawn soap, easy! -- but
they no longer make *glass* "executive" bifocals.)
He said alcohol, eg rubbing alcohol. I asked with paper towels,
Bounty paper towels, he said yes, but ONLY bounty, only that
brand wouldn't scratch.
Note: (seemingly unlike most of humanity), I'm really sensitive to
having *any* smudge on my glasses. So much so that I often get
some soap (dawn, of course, very diluted) and wash my face with it,
over the kitchen sink, to get rid of all those skin-secreted
oils that would work their way from my nose onto the edge
of the glasses.
Which shows how important to me it is to have super-clear lenses.
So, is he correct? Or what?
Thanks!
David
Richard J Kinch
> So, is he correct? Or what?
Cleaning plastic eyeglass lenses: Rinse in water to remove grit. Rub
gently and briefly to remove oily film with diluted Dawn using only wetted
fingers. Rinse. Tap to remove most water. Dab dry with paper towels,
don't rub.