Natural Science Forum / Physics / Optics / July 2008

On Jun 29, 9:20 am, jmch...@nb.sympatico.ca wrote:

Sir;

Your cleaning advice is close to dangerous.  The critical one is:

Always clean wet, not dry.
(repeat endlessly)

If is crucial to clean wet.  Your trying to float the dirt up and
either into the cleaning tissue, not trying to rub it in deeper.
Remember if you clean dry you will scratch either the glass or the
coating material.  By the way, coating material is mostly harder than
glass so you want as much coated glass as possible.  For a cleaning
solution use any high vapor pressure chemical, however most high vapor
pressure chemicals are rather deadly so I recommend alcohol, heptane
and water based cleaner like Windex or Sparkle.  Heptane is safe but
hard to get so mostly alcohol will have to do.  Make sure your work
area is well ventilated.

It is not crucial to capture the dirt in the cleaning tissue, if you
can push it to the edge that's good enough, usually.  You want the
glass area used by the instrument to be scrupulously clean though.

The cleaning material can be Kim-Wipes of a simple Tissue like
Kleenex. Don't purchase tissues that have lotions on them that protect
your nose, they just won't work.   I use Kim-Wipes since they are
readily available but when push comes to shove I've used Kleenex and
Publix brand tissues.  You may have to clean the surface off with
either canned air or an ear syringe (!) but both work well to get rid
of dust.  Tissues just add a bit more dust to the equation.

Dip the tissue into the water based cleaner then into some alcohol, I
use Menda bottles but they're expensive.  Start from the center and
wipe to the edges.  Throw the tissue away.  Repeat until clean.  Wipe
in the same pattern with a dry tissue to remove moisture.  If your
only using alcohol, depends what's on the lens, then you probably
won't have to wipe it dry, just shake the tissue about three times or
so and wipe from the center out.

Camera lens cleaners don't work for cameras, my wife used to own half
of a camera repair company, they just get the dirt mad at you.  The
green lens cleaner that just about ever one buys is worthless, its a
mixture of vinegar and water essentially.

If your cleaning objectives go to Wal-Mart or a good hardware store
and buy a cheap, small LED flashlight so you can illuminate the area
your cleaning either from the front or back.  That helps you visualize
the dirt.  Use a reversed eyepiece as a magnifier.  If you need a
longer reach to get to the back of an objective use a whole Kim-Wipe
and wrap it around a diamond holders tweezers (a long reach,
relatively soft tough tweezers) with a lot of Kim-Wipe hanging of the
front.

Be gentle but be firm.

Then there's lubricating, disassembly, etc.

I don't want to stop you or discourage you from writing about
microscopes but you might want to consult with your local technical
people.  I've been in the craft of microscopes since '78, it is not
the simplest field in the world.  They're is a lot to learn, from
cleaning to electronics to physics to mechanical engineering and I
don't know it all, I learn every day.

Thanks,

Kevin Cunningham
SMS