Subject: cleaning brass clock movements

From: [email-masked] (Wm. Congreve (Sr.) )
Date: 2 Oct 1995 16:50:03 GMT

I have to disagree with a previous post on this.  The great majority of
skilled repairers of brass clock movements clean in a water-based,
ammonia/oleic acid (ie soapy) solution, followed by a rinse in a fairly
volatile organic solvent.  The largest manufacterer of such solutions
for the clock trade is "L & R" and their products are available in most
cities at a clock/watch repair supply place.  For watches, where a more
expensive (less volume involved) cleaning solution can be used, an
organic cleaner often replaces the water/ammonia solution.

It has been noted among some careful repairers of 18th century clock
movements, which were of cast brass, that if you leave it soaking in
the ammonia/water/soap solution for too long, it can get into micro
cracks in the brass and cause problems.  The answer even with those
very valuable pieces is simply to put gloves on, get in a ventilated
place, and scrub with a soft brush or rags as needed, so the brass
doesn't stay in the ammonia too long, and then immediately go to an
organic rinse which will displace the water.  With 20th century
rolled-brass that surely shouldn't be a problem.

If the plates of the clock have been lacquered, you may well get a
milkiness problem, UNLESS you use gentle mechanical means to get the
lacquer off off in the cleaning stage, and then use the organic solvent
rinse, and then very promptly dry with cloths or a big box of sawdust
(which is the traditional means).  

The wheels of the clock are very rarely found to be laquered, only the
plates.  

The most crucial thing of all is to NEVER try to clean a clock movement
worth more than $5.00 except after complete disassembly, including
taking the spring out of the barrel, if it's in a barrel.  Anything
less is just going to lead to an expensive professional job.

              Alan Heldman