[sdiy] Why Acetone might actually be best for cleaning 'conductive rubber' contacts

[Bob Weigel]

Chris wrote:

You gotta be kidding. Acetone on rubber contacts...???
Generally I use aetone only in those cases when pure alcohol won't
suffice. Pretty nasty stuff, easily solves plastic etc.

Chris
--------------

Chris,
THat's..what I thought. However Andy has serviced a ton of stuff.  aka 
'the circuit rider', Montana's main Organ repair guy but he's also done 
a lot of Kurzweil and and synth stuff.  So I gave consideration to the 
idea a little deeper.
     As we know solvent's properties vary surprisingly often in how they 
interact with various materials.  (Like I found back in the old days 
when I tried some silicon lube on a key to my K3....and it melted the 
surface!  )  Acetone is very volatile and one thing for sure; if it 
doesn't react with the rubber in a bad way in the first minute or so 
it's gone and won't cause future problems.  Contact cleaner that I used 
(can't recall which one for sure) caused the material to swell that was 
NON-conductive (this 'conductive rubber' is some kind of manufactured 
slurry of rubber and conductive material I believe.  Anyone know the 
manufacturing details there?)  part to swell!  Hence making it so you 
got no contact at the surface.  All the non-conductive rubber was 
microscopically sticking out to prevent it!.
     Acentone may actually  work in kind of the opposite way.  Andy 
calls it a 'glaze' and maybe what it really is...is a surface where 
microscopically the conductive portion has worn away more quickly than 
the non-conductive rubber.  Think about it. This makes sense.  As you 
front impact rubber, it doesn't wear. At all. Conductive material 
however...even microscopic lateral abrasion wears away a few atoms at a 
time.  And eventually you have to hit it harder and harder to get a contact.
     So the solutions are

1) use as I do a lateral abrasion which levels the entire surface again 
so that there is again an exposure of the conductive material or

2) use a solvent that actually does briefly dissolve away some of the 
non-conductive material but leaves the conductive alone.

-Bob

ChristianH wrote:

On Wed, 22 Jun 2005 21:30:00 -0700 Bob Weigel <sounddoctorin at imt.net> wrote:


>I usually use the 'pull the key and use mirror grinding technique to 
>deglaze the contacts' technique. Andy Seitz tells me he has success with 
>acetone on the contacts. 
>  
>