Limits of Flush Cleaning - Steven K Grimes
In response to a suggestion of taking an intact shutter to a watchmaker for ultrasonic flush cleaning:
Date: Fri, 5 Feb 1999
No. Some of the mechanism, after disassembly can be cleaned in the ultrasonic
cleaner. Ultrasonic cleaning can, in some circumstances etch some parts
and damage them. Ultrasonic cleaning is *not* a substitute for disassembly.
And look, I don't mean to
belabor the point but the contaminants involved in "dip cleaning"
do not come from the cleaner/solvent. There are lots and lots of solvents
that don't leave any residue *on their own* The residue comes from the
mechanism itself, not the solvent. And it doesn't take much residue to
screw things up. Yes, I suppose that theoretically you can dilute and
change the solvent enough times that the residue becomes negligible, but
as a practical matter this doesn't happen.
So, in my experience, "residue
free cleaners" are misleading because it causes you to hope that
it will make the oils and greases *not in the solvent originally* somehow
disappear. (Sort of like the time you waste trying to patch a car muffler
before replacing it)
SKG
In response to a discussion about the relative merits of using lighter fluid, carbon tetrachloride or Fargo shutter cleaner as a solvent for dip or flush cleaning shutters:
From: "skgrimes" skgrimes@ma.ultranet.com
Newsgroups: rec.photo.equipment.misc
Subject: Re: Unsticking a shutter.
Date: Thu, 4 Feb 1999
Although there are those who
occasionally get lucky the method of dipping a shutter in solvent (any
solvent including mysterious secret miracle solvents) does not work. All
the efforts at different oils and inspections for wear in the pivots etc
is an entertaining sport which will probably not repair the mechanism.
What happens with solvent dip cleaning is that the contaminant schmutz/grease/whatever
which was causing some part to stick is not removed but is actually thinly
diluted and spread throughout the mechanism. So that a mechanism which
was dirty in some parts and clean in others is now evenly dirty all over.
In this specific case what happens when the lighter fluid dries out is
that the remaining grease causes the shutter blades to adhere to one another
and/or otherwise bind up. In halfway/amateur repairs its best to:
- Try just a drop or two of solvent on the star/pallet mechanism first. Then if that doesn't ----
- Remove the slow governor from the shutter and dip/solvent/compressed air clean just that mechanism.
- Taking copious notes/ digital
photos and/or using a duplicate sample shutter, disassemble the shutter
to clean
the parts.
Once a shutter has been solvent
dip cleaned and on top of that had its other parts filed, bent, greased
and twisted to try to compensate for damage thus done it is usually no
longer practical to repair, even by an experienced skilled mechanic. --
--- S.K. Grimes -- Feinmechanik ----