[Amps] Surface Cleaning Tarnished Aluminum "YC156"

[sanorm at columbus.rr.com]

Looks good but you just lost all the silver plating on the YC156 anode 
fins.

  Norm N8NH

----- Original Message -----
From: k7rdx <k7rdx at charter.net>
Date: Tuesday, April 24, 2007 1:58 pm
Subject: Re: [Amps] Surface Cleaning  Tarnished Aluminum
To: Larry <larry at w7iuv.com>
Cc: 'Amplifier- List' <amps at contesting.com>

> A much diluted batch of muriatic acid eches alum really 
> well,followed by
> rinse in water. Also works really well for cleaning silver plated
> parts,ceramic tubes,etc...Dip in/out fast depending on dilution 
> ratio,fullstrenght might eat the part..Vinegar cleans alum super 
> well as does glass
> cleaner..I have cleaned a few yc-156`s in muriatic acid full 
> strength and
> they look like new...Takes a few seconds followed by flushing with 
> cleanwater and blow dry..Got wind?73,Jim..
> ----- Original Message ----- 
> From: "Larry" <larry at w7iuv.com>
> Cc: "'Amplifier- List'" <amps at contesting.com>
> Sent: Tuesday, April 24, 2007 10:18 AM
> Subject: Re: [Amps] Surface Cleaning Tarnished Aluminum
> 
> 
> > Robert Bonner wrote:
> > > 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.
> > >
> > I gotta jump in here.
> >
> > Lye, if used with a bit of intelligence, does not "dissolve" 
> aluminum.> At least not any more then you would want to in the 
> first place. I use
> > the stuff all the time on aluminum and it works great for 
> putting a nice
> > matte finish on parts and is a reasonable surface prep prior to 
> painting> if you don't have the resources to do a professional prep.
> >
> > As far as the air variable cap surfaces, all the Johnson and 
> Caldwell> caps I have seen appear to have had the plates tumbled. 
> Depending on the
> > tumbling media used, the surface can be nicely de-burred down to 
the
> > microscopic level and leave anything from a matte to a polished 
> finish.> Although I have the resources to tumble small parts, I 
> don't have to
> > patience to do it. A proper job may take several days depending 
> on the
> > media used and the type of "polish" desired.
> >
> > If I were to re-build a air variable with the resources I have 
> here, I
> > would dis-assemble it and using 400 grit wet-or-dry paper 
> carefully take
> > off the high spots. Then I would do a light etch with lye (sodium
> > hydroxide). The lye will etch away all the microscopic ridges 
> left by
> > the sandpaper and leave you with a nice matte finish that will 
> look good
> > under the microscope. Any "potholes" that might be left on the 
> plates> won't matter as long as there are no high spots or sharp 
> shapes or edges.
> >
> > As has been said here recently, never dump parts in lye that 
> have blind
> > holes tapped into them. I have not had any problem with drilled 
> and/or> tapped holes in sheets or plates, but have had a bit of 
> trouble with
> > blind holes. Of course, I use a lye concentration suitable for 
> the job
> > at hand and watch it all the time it's in the bucket.
> >
> > The acid wash has always been a problem for me as the acid I 
> would like
> > to use is much more difficult to obtain then sodium hydroxide. Has
> > anyone used white vinegar for this?
> >
> > 73, Larry
> >
> > -- 
> > Larry - W7IUV
> > DN07dg
> > http://w7iuv.com
> >
> > _______________________________________________
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> 
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