PDP-8/a cleaning

allison allisonportable at gmail.com
Tue Apr 25 08:51:23 CDT 2017

On 4/25/17 8:57 AM, Paul Koning via cctalk wrote:
>> On Apr 25, 2017, at 6:06 AM, Pete Turnbull via cctalk <cctalk at classiccmp.org> wrote:
>> On 25/04/2017 10:08, jim stephens via cctalk wrote:
>>> On 4/25/2017 1:39 AM, Pete Turnbull via cctalk wrote:
>>>> "Little residue" would be more accurate, and some of that residue
>>>> will be water (look up "azeotrope") - plus you need a lot of
>>>> alcohol for something the size of a PDP-8 backplane.  Blow dry,
>>>> even after an alcohol rinse.
>> I should perhaps have mentioned that the idea is to flush the remaining
>> water or alcohol out by blowing, not evaporate it like your hairdresser
>> would :-)  And you ought to use dry air, ideally - most compressors have water in their air.
> Worse yet, a lot of compressors have oil in their air.  You can attached a dryer/filter to the compressor outlet to block that.  Compressors intended for air brush use tend to be set up that way, and/or use a mechanism that doesn't use oil (such as a diaphragm pump).
A water trap/oil filter is a trivial thing to add.  Most come with a 
regulator which is handy.
However,  Generally the water and oil content is low to start with 
unless the compressor
is seriously worn or your taking air form the bottom of the tank. 
Normally its good
practice to drain the tank of water anyway.  I've painted a few things 
in my day like
racing cars.

The alternate is a canister of nitrogen gas or cans of "air".  The 
quantity needed
is not all that great.

Even after all that I'd still dry it with a little heat (oven at 180F or 
a clean empty
container in the sun.

I've used the dishwasher (sans caustic dish detergent) for cleaning then 
in the
oven to dry  for radios, computer boards, analog boards, and assemblies
that can trap water.  Things that turn or move like switches (open wafer 
for example)
need to have contact treatment and bearing lubrication afterwards.

> 	paul

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