Re: {Collins} 2-Propanol as cleaning agent for rotary switches.

I think the W8ZR's statement below is good. There are different levels of  
Bakelite quality and different types of filler material used in making 
Bakelite  switch wafers depending upon manufacturer and cost. While Collins  
obviously employs the highest quality Bakelite parts some of the less  expensive 
competition does not which is probably where this caution came  about. It 
would be interesting to repeat the W8ZR test using switch wafers  from other 
popular equipment manufacturers. 
I have always thought moving mechanical parts and sliding metal contact  
surfaces should be lubricated for smooth operation and to prevent premature 
wear  but I have not done a study to confirm if that is actually the case. The 
 obvious argument against applying a lubricant is that it might introduce 
an  insulating layer but is that actually true? Has anyone tested for  
resistance using various lubricants on switch contacts? I know a lubricated  
multi-stage wafer switch assembly is a lot smoother to operate and it does seem  
to eliminate intermittent operation. Of course we all know silver oxide is 
an  excellent conductor so is it really necessary to remove it?
I would guess that microwelding would be another way to say  galling.
In a message dated 6/28/2014 9:21:30 A.M. Eastern Daylight Time,  
4cx250b@xxxxxxxxxxx writes:

Hi  Bent,

A recurring myth among Collins collectors is that one must be  very cautious
using solvents or water around the rotary switches in the  S-line. The
concern is that the phenolic wafers will absorb water or other  cleaning
agents, causing the wafers to swell and soften, thus leading to  
damage to the switches. Some owners avoid using De-Oxit D5 on  rotary switch
contacts for the same reason.

A few years ago,  I conducted an experiment in which I completely submerged
in water for 24  hours a Collins wafer switch removed from a piece of S-Line
equipment, and  then I repeated the experiment in De-Oxit D5 for 24 hours. I
measured the  wafer thickness with a micrometer before and after this
treatment to check  on possible swelling, and also inspected the wafer for
contact loosening or  other problems. To my surprise and pleasure, the wafer
was completely  unaffected by this treatment. The only effect of the DeOxit
D5 on the  switch was to make the contacts look shiny and bright. I'm
unfamiliar with  2-Propanol, but my general impression is that the wafers in
Collins  switches are extremely durable and resistant to water and other
cleaning  agents.  I wrote up the details of my experiment on this 
so  presumably it can be found somewhee in the archives.


Jim  W8ZR

>Is someone able to inform me whether 2-Propanol can be  used as a cleaning
agent for the rotary switches in the KWM-2  etc.

>According my knowledge it should be water  free.

>If not, what is then recommendable  ?

>Thanks in advance.

>Best  regards



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