[SCCC] Copper Paste

Sun Jun 12 09:36:35 PDT 2011

Apply it the same way as you did the Penetrox (inside the joint).

Yes, silicone grease is a dielectric.  So is the petroleum-based 
carrier in the Penetrox.  The silicone material is more inert and 
doesn't disappear like the petroleum-based stuff will do, leaving the 
unprotected particles of other material in there.

If you looked at the aluminum surface with a microscope, after prep, 
you would of course see a rough landscape of bumps and grooves-- not 
smooth.  When the two surfaces are mashed together tightly with a 
hose clamp, and a screw added, don't worry-- plenty of the high spots 
are going to mate up with other high spots, regardless of the 
presence of the dielectric, and make contact.  That is the series of 
multiple contact points from which we are trying to eliminate the oxygen.

The various 'conductive pastes' are ok in the short term, but 
eventually the carrier deteriorates and we are left with oxidized 
particles of other material in there, and it's probably no longer 
conductive.  In the long term, this is bad news.

IMHO....

--Glenn K6NA

At 08:33 AM 6/12/2011, you wrote:
>Glenn,
>
>Isn't silicone grease an insulator? Or are you saying keep it out of 
>the joint itself but coat the exterior of the joint once the two 
>pieces of aluminum are slid together? What we used to do with our 
>KLM antennas is clean the aluminum where the two pieces slide 
>together, coat the outside of the smaller piece with Penetrox, coat 
>the inside of the larger piece with Penetrox, slide the two together 
>and clamp securely.
>
>--Dennis
>
>
>----- Original Message ----- From: "Glenn Rattmann" <k6na at cts.com>
>To: "Bob Wilson" <N6HB at n6hb.org>
>Cc: <sccc at contesting.com>
>Sent: Sunday, June 12, 2011 8:06 AM
>Subject: Re: [SCCC] Copper Paste
>
>
>>If folks don't like what they are reading here, just go to the
>>endless archives on Tower Talk and find another opinion you like better! ;-)
>>
>>Any of these items mentioned will work adequately for a while (except
>>for Cu - Al-- a bad recipe for antennas, I have seen really bad
>>results with that).  Zinc or aluminum particles in the mix are the
>>'least dis-similar' metals for the aluminum joint.  However, the
>>primary way these products work is by keeping oxygen and moisture out
>>of the connection.  That's what will prevent aluminum
>>oxidation.  Over time, the carrier tends to vaporize or dry out, and
>>the moisture/oxygen start doing their business.
>>
>>Dennis mentioned "We know aluminum to aluminum causes a black
>>corrosion in short order."  I don't think that's true.  The initial
>>aluminum oxidation layer is basically colorless-- you can't see
>>it.  After a very long time, it may be white.  It's an
>>insulator.  What Dennis mentioned I think is the remnants of old
>>No-Al-Ox or Penetrox, which leave behind a dry, black insulating
>>layer after the carrier washes out or vaporizes.  Eventually coupled
>>with the aluminum-oxidation layer, the hard black layer of gunk makes
>>it even worse.
>>
>>High-vacuum silicone grease (o-ring grease), with NO particles mixed
>>in, is the simplest anti-oxidation material to put in there.  Use a
>>tight, stainless hose clamp around the slotted end, and add one s.s.
>>tapping screw (coat the threads, too) behind the clamp, into both
>>layers of aluminum.  I've taken apart joints like this after 20 years
>>and they are still fine.
>>
>>Remember though, even your brand-new aluminum tubing comes to you
>>already oxidized (insulated!).  Remove this invisible layer before
>>you mate the joint.  Use non-metallic grit sandpaper, wipe clean with
>>lacquer thinner, and then QUICKLY coat both halves of the joint with
>>the grease.  A fresh aluminum surface oxidizes in just minutes, so
>>the key is to cover the fresh surface immediately with the goo to
>>eliminate the oxygen.  Then mate the pieces.
>>
>>Oh-- don't have any silicone grease handy?  Just use common
>>wheel-bearing grease.  The next time N6ND beats you out in a pileup,
>>you can think about the common grease in Rick's antenna joints.
>>
>>73,
>>
>>Glenn K6NA
>>
>>At 09:59 PM 6/11/2011, you wrote:
>>>Noalox is the "gold standard" - I've seen it at Home Depot in the squeeze
>>>bottles you refer to AWA small tubes. I've also bought large containers at
>>>electrical supply houses and used it for a Caribbean contest expedition. We
>>>donated the antennas, and I heard back 5 or 6 years later that they came
>>>apart like the day they were put up.
>>>
>>>-Bob
>>>
>>> > -----Original Message-----
>>> > From: sccc-bounces at contesting.com [mailto:sccc-bounces at contesting.com]
>>> > On Behalf Of Daniel Severance
>>> > Sent: Saturday, June 11, 2011 8:39 PM
>>> > To: Timothy Coker; Dennis Younker NE6I; SCCC
>>> > Subject: Re: [SCCC] Copper Paste
>>> >
>>> > Noalox (or any of the other variants) is what I've been told to use as
>>>well -
>>> > without it over time the pieces will weld together so you can't even
>>> > disassemble to clean up joints.  I have had experience trying to
>>>disassemble
>>> > and antenna which has fused in places.  Definitely use one of 
>>> the > products
>>>-
>>> > the Noalox comes in a bottle which looks like an old elmer's 
>>> glue > bottle,
>>>at
>>> > least for one of the sizes (if that helps you find it)
>>> >
>>> > Cheers,
>>> > Dan
>>> >
>>> >
>>> >
>>> > ________________________________
>>> > From: Timothy Coker <n6win73 at gmail.com>
>>> > To: Dennis Younker NE6I <ne6i at cox.net>; SCCC <sccc at contesting.com>
>>> > Sent: Saturday, June 11, 2011 10:42 PM
>>> > Subject: Re: [SCCC] Copper Paste
>>> >
>>> > Noalox from Lowes is what I have been using. It's meant for aluminum
>>>joints.
>>> > $9 for 4oz or so.
>>> >
>>> > 73,
>>> >
>>> > Tim / N6WIN.
>>> >
>>> > On Sat, Jun 11, 2011 at 7:38 PM, Dennis Younker NE6I 
>>> <ne6i at cox.net> > wrote:
>>> >
>>> > > Hmmm. We know aluminum to aluminum causes a black corrosion in short
>>> > order.
>>> > > That corrosion is an insulator.  We also know that dissimilar metals
>>> > > cause corrosion. I hadn't thought about copper to 
>>> aluminum > > previously.
>>> > > In my past experience though, Penetrox applied to aluminum 
>>> yagis was > > a
>>> > > positive experience. Penetrox was shipped with KLM antennas 20+ years
>>> > > ago. I've been out of touch since then.
>>> > >
>>> > > Your suggestions of products at Home Depot is intriguing.
>>> > >
>>> > >
>>> > > --Dennis, NE6I
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