As with most issues, "it depends". Passivation of SS is a process used
to make SS alloys less chemically reactive. SS is an alloy of Cr, Ni,
Fe and other metals & C in a matrix and if the Fe is removed at the
surface the reactivity (EMF differential) is reduced. This also makes
the SS less likely to show rust pits. Fe and Al are far apart on the
EMF scale so passivation is very desirable if SS is used to fasten Al.
ie Al "sacrifices" to Fe.
The SS alloy also makes a big difference - 18-8 is the most common
fastener alloy. 316 is a better alloy choice and 316L is used when
welding marine structures since it has less carbon, which in the actual
weld promotes free iron and therefore rust. Better, generally
available, but more expensive. The next step in corrosion resistance is
Monel, mostly nickel and now the fasteners are getting really expensive,
but Ni is closer in EMF to Al.
The EMF differential of Zn vs Al is the lowest of any practical metal
assembly with Al. So Zn is very compatible with Al even though the
reaction is one to slightly sacrifice the Al. Zincate is a Zn plating
process that prepares Al for further plating - copper, nickel, etc. The
Zn bonds very well to Al, which otherwise is very hard to plate either
with electrolytic or electroless processes.
The Zn particles in the popular corrosion inhibitors I think are more of
"compatible ball bearings" than corrosion inhibition. Beam elements
I've disassembled after 8 years protected with Penetrox came apart
pretty easily. I don't use Cu carrying protection on Al to Al per the
manufacturer's recommendations.
Also, hot dip galvanized fasteners are a good choice for larger bolt
sizes. Available 1/4-20 and up, they are cheaper than SS, don't gall,
and are very compatible with Al.
Grant KZ1W
On 2/15/2018 19:52 PM, Kim Elmore wrote:
From this thread, I learned that stainless steel and aluminum are a corrosive
combination. I hadn’t heard this before.
I’ve known that copper and aluminum are a corrosive combination and so the Jet
Lube SS-30 surprises me. But I also wonder about zinc (the main component of NoAlOx,
OxGard, and Penetrox) and aluminum. Is that truly a combination that plays well
together?
Kim N5OP
"People that make music together cannot be enemies, at least as long as the music
lasts." -- Paul Hindemith
On Feb 15, 2018, at 18:44, Kim Elmore <cw_de_n5op@sbcglobal.net> wrote:
I asked the question to make sure something was needed for Al-to-Al and it seems it is
truly is. Long ago, I was told that Al-to-Al was best dry because galvanic corrosion
couldn’t
When I was In CO, I used some stuff called OxGard because it was supplied with
an antenna. It seemed to work well there, but CO is very dry. OxGard has a
petroleum grease containing graphic and zinc particles. After about 10 y in CO,
everything seemed fine and when I took the antennas apart to move to OK, the
grease was still greasy. I used it when I reassembled the antennas here. But, I
always wondered if the stuff was truly necessary.
Kim N5OP
"People that make music together cannot be enemies, at least as long as the music
lasts." -- Paul Hindemith
On Feb 15, 2018, at 16:45, Keith Dutson <kdutson@sbcglobal.net> wrote:
May have something to do with weather conditions. I noticed Penetrox seems to
dry out quicker here.
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Bill M
Sent: Thursday, February 15, 2018 4:24 PM
Cc: towertalk@contesting.com
Subject: Re: [TowerTalk] Al-to-Al
We found when we took older antennas down where Penetrox was used were corroded
together or extremely hard to separate. We went to Noalux 30 years ago and
haven’t looked back.
Bill W2CQ
On Feb 15, 2018, at 9:05 AM, Keith Dutson <kdutson@sbcglobal.net> wrote:
Cannot find Noalox here in these stores in Houston. Penetrox is available, and
I keep a supply in the shack for general use. Seems to be pretty much
identical to Noalox for my use.
73, Keith NM5G
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
john@kk9a.com
Sent: Thursday, February 15, 2018 7:17 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Al-to-Al
Noalox seems to be more available at the big box stores, I wonder why Penetrox
became popular with amateur antenna builders.
John KK9A
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Al-to-Al
Date: Wed, 14 Feb 2018 16:09:29 -0500
We’ve tried pretty much everything in our salt air environment of South
Florida. Most here use Noalux successfully over the past 30+ years.
Bill W2CQ
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|