[Amps] Surface Cleaning Tarnished Aluminum

[Robert Bonner]

I thought we covered this last week.  You don't want to use LYE on aluminum
unless you want it to GO AWAY.  It dissolves it, acid works more controlled.
Lye would cause more pits.

You are probably better off sanding with fine sand paper and then polishing
with polishing compound and a buffing wheel.

I have never gone to this extreme for a cap myself.  Back when I was a kid,
I painted a few with corona dope to raise their breakdown voltage.

Some of the HAM companies are placing mylar or Teflon sheeting between the
plates to raise voltages.  Then you rough surface wouldn't matter.

BOB DD

-----Original Message-----
From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
Behalf Of k7rdx
Sent: Tuesday, April 24, 2007 11:39 AM
To: Vic K2VCO; w2cqm at juno.com
Cc: amps at contesting.com
Subject: Re: [Amps] Surface Cleaning Tarnished Aluminum

If you treat the aluminum with a caustic chemical to clean,remove
pits,etc.You MUST polish to a high shine if you want to maintain it`s
voltage breakdown rating.Rough aluminum is like two sharp surfaces close to
each other...Zapppp!!Do as Vic suggests if you have time and patience,or
just purchase a new cap..You may also wish to have the cap parts re-anodized
after polishing...If you don`t the cleaned&polished aluminum will oxidize in
a matter of time ruining your hours of work...My oh my,Jim, K7RDX..
----- Original Message ----- 
From: "Vic K2VCO" <vic at rakefet.com>
To: <w2cqm at juno.com>
Cc: <amps at contesting.com>
Sent: Tuesday, April 24, 2007 8:49 AM
Subject: Re: [Amps] Surface Cleaning Tarnished Aluminum


> w2cqm at juno.com wrote:
> >
> > I'd like to clean a pocked marked  air variable aluminum capacitor by
> > etching the surfaces. Is there some commercial or hombrew product I
> > could use to dip the component and achieve that result? Any
> > suggestions would be appreciated. Ron W2CQM/3
>
> I've done this by taking the capacitor apart and using 400 and 800-grit
> sandpaper, such as is used for automobile finishing, followed by
> polishing on a buffing wheel.  Although lye will etch aluminum, it
> doesn't give a smooth finish, and I don't know how you'd get the residue
> off without taking it apart anyway.
>
> -- 
> 73,
> Vic, K2VCO
> Fresno CA
> http://www.qsl.net/k2vco
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> Amps at contesting.com
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>

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