Archived posting to the Leica Users Group, 1999/04/30

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Subject: Re: [Leica] Keeping an M shutter in shape
From: "4Season" <4season@boulder.net>
Date: Fri, 30 Apr 1999 23:56:40 -0600

The idealb storage of a Leica camera is actually more involved than it might
seem at first glance: Besides the matter of metal fatigue caused by
long-term storage of a mechanism under tension, the effects of oxidation and
atmospheric pollutants will all serve to degrade the long term performance
of an M camera.

The following procedure is useful:

(1) Visible debris removed with pressurized CO2

(2) Optics surfaces cleaned with ROR, followed by distilled water.
Unfortunately, most commercially available distilled water is distributed in
plastic bottles, which tend to leach out over time. The best advice I have
to offer is either to distill it yourself, else request glass containers.

(3) External camera surfaces cleaned with a 1:50 solution of Liquinox
detergent and distilled water, applied with slightly damp Kimwipe, or
similar contaminant- and lint-free cloth. For best results, the cleaning
solution temperature should be 30-35 degrees C. Liquinox is particularly
effective against proteins, such as those left behind by your fingerprints,
or even blood! Follow this with distilled water.

(4) Obtain a airtight storage container made of some non-reactive material.
Teflon, stainless steel and borosiliate glass are common choices, and
entirely satisfactory. The best gaskets are those made of silicon rubber.
Glass housings are especially desireable, for inspection purposes. You may
also want to enclose a small combination thermometer/hygrometer, as sold by
Light Impressions and others.

(5) Place within the storage container, the camera, with bottom cover and
back removed, and with film advance lever partially advanced (the exact
amount is not critical). Do not use a body cap: As much as possible we want
the innards of the camera exposed for the next step...

(6) Fill the container with nitrogen (readily available from most chemical
supply houses-inquire when you pick up your Liquinox), argon or other inert
gas. Be careful to introduce the gas slowly, in order to minimize sudden
chilling. We are seeking to displace the oxygen and hydrogen in
particular--no oxygen, no oxidation. Hydrogen is really only a problem at
high pressures, in which it tends to penetrate the walls of it's metal
container and turn the metal brittle, but why take chances? Seal the
container. Pressure is not critical, but it's best to be a bit high than a
bit too low--vacuum-sealing your Leica would be a bad idea, since the
lubricants will literally boil away, and leave a yucky film all over your
finder windows!

(7) Over a 24-hour period, gradually lower the temperature of your storage
container to just over freezing--3-5 degrees C would be ideal. a day before
going on a shoot, reverse the process, bringing the temperature back to
ambient.

Cared for thus, your Leica M will continue to look and perform like new for
many, many years. The process is somewhat cumbersome and requires advance
planning, hence, I myself use a slightly modified version, easily memorized:

(1) The Red Dot Is Your Friend: If you can still make it out, your camera is
probably clean enough. If not, wipe it with old underwear or your shirt,
whichever seems cleaner.

(2) Don't go about "half-cocked"

Jeff

- -----Original Message-----
From: Peter Niessen <niessen@ifh.de>
>I wonder how one could spare the springs in the M's shutter. Is it a
>good idea just to cock the shutter half ways when not using the camera
>for a longer time? My theory is that the every curtain spring takes
>only half the load and wear on them will be more evenly distributed.