[ARC5] [Milsurplus] roller inductors

[Richard Knoppow]

    Thank you for the measurements.  I found some of the papers you cite 
and downloaded them. I am not either an organic chemist or a metalurgist 
so some of the material is beyond me.  However, it would appear that 
when there is mechanical action as in rotary switches and wiping contact 
relays and probably the roller inductor, the tarnish, of whatever kind, 
probably has little effect.  I suspect that what makes switches noisy or 
intermittent is more likely dirt than tarnish, especially since there 
are many switches and relays that are not silver plated or solid silver 
alloy. For isopropyl alcohol, AKA isopropanol, "pure" usually means dry. 
Isopropanol will absorb moisture from the air until it reaches 91%, 
rubbing alcohol has usually 30% water but can have up to 50% water.  Dry 
alcohol must be kept in tightly capped bottles. I think the spray kind 
likely stays dry longer.  This stuff evaporates without leaving moisture 
behind. It is also currently recommended by Kodak for cleaning the 
_emulsion_ side of negatives and transparencies because alcohol with 
moisture in it will cloud them.  It is NOT safe to use on the support 
side because some kinds of support (cellulose acetate or nitrate) are 
attacked by it. Its a decent degreaser.  I think the lesson is that 
while cleaning silver plated parts make them look better they may not 
work any better and may eventually be damaged by the cleaning.  Again, 
thanks for the research.

On 1/26/2016 10:07 AM, Bill Carns wrote:
>
> It is always good to have actual “Data”.
>
>

-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL

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