[Amps] Surface Cleaning Tarnished Aluminum

[Barrie Smith]

----- Original Message ----- 
From: "Robert Bonner" <rbonner at qro.com>
To: "'Amplifier- List'" <amps at contesting.com>
Sent: Tuesday, April 24, 2007 10:40 AM
Subject: Re: [Amps] Surface Cleaning Tarnished Aluminum


> 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.

This technique would raise the capacitance as well, wouldn't it?

Barrie


 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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> >
>
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