[SCCC] Copper Paste

[Glenn Rattmann]

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