> Following the advice of those who trod before me, I purchased
> some anti-seize thread compound to use in my turnbuckles.
> I ntoiced this goo seems to be copper based, and my turnbuckles
> are galvanized...Did I just make a nice battery that will eat
> the zinc plating off my turnbuckles? Tell me it isn't so...
>
> 73, J.P. W2XX
>As we say in the software business: "You are hosed."
J.P.
You may not be completely "hosed"! The evidence of the galvanic reaction
will not show up until the petroleum grease gets washed out of the threads.
Then the acidic rain water or saltwater (electrolyte) can get in there and
do its thing. This may take a few years.
Check the turnbuckles every 6 mos to insure that they still turn. Even if
the zinc gets stripped, the connections should still come apart.
This assumes that you selected forged turnbuckles. The density of the steel
is higher than the annealed copper normally used in the compound. The
copper will lose the battle. After this, use a zinc based compound.
>Usually it is mostly aluminum dust with a trace of copper dust, I suspect
it will be O.K.
Great! The less copper the better!
>It will be between two galv. surfaces and the two batterys will be of
reverse polarity (to each other) and any voltage should cancil. >There
should not be a current.
>73 de Ron ka4inm@qsl.net Best Regards
Not sure I follow this one?
Eventhough, the two cell battery has symetry, the potential will still
exist between the copper and zinc.
"Accelerated corrosion can occur between unprotected joints if the
algebraic difference in atomic potential is greater than +/- .3 volts."
(Taken from Polyphaser "Grounds for Lightning and EMP Protection, second
edition, page 18). Our corrosion reference book, at work generally agrees
with this value.
When the connection loses the vehicle and all that is left is the copper
particles, zinc plated surface and moisture, a potential of 1.10 volts will
be developed. Initially this only occurs around the edges of the copper
particles. The mating faces of the particles and zinc that are pressed
together by the load of the tightened connection will take quite a while to
deteriorate, as the moisture has a hard time getting into the interface.
>As I posted to this thread about a week ago, I use regular grease on all
>my galvanized turnbuckles.
>Bill, N3RR
This is not an altogether bad choice, depending on the type of grease used.
I would recommend a waterproof marine type grease. It lubricates the mating
zinc faces to prevent them being worn off when tightened. At some point in
time, the grease can leave, depending on the environment. When the
turnbuckles are subsequently tightened or undone, the turning under load
can strip some of the plating, making the next use more difficult.
>not all anti-seize is copper base....the stuff I use is steel base ( I
>guess since it is "gray") - it is automotive goo - I but a bottle of it
>from NAPA for about five or six bucks....this is enough to do a tower
>installation, and lid has a handy brush attached to it...ez2u (easy to
>use)
>73, Jim, K4OJ
I think that "Silver" is aluminum, "gray" is zinc, "copper" is copper, and
"black is graphite. The lead based compounds I've used are also "gray,"
just a little darker than the other one "gray" ones. For galvanized
materials I'd pick the "light gray."
>It's probably fine. I'm using the same on mine as is W3LPL. I forget the
>exact brand,
>but I think it's called Jetlube or SS20.
>73, Ty K3MM
J.P., Your in good company here. We'll stay tuned.
The thing that determines what one should do, or can get away with, is the
environment the connection will be exposed to and the time duration you
need it to perform in. The wetter and saltier your environment, the shorter
your fuse, if you put dissimilar materials together. If you live far from
the ocean, and aren't in the middle of a wet polluted industrial area,
you'll wonder why we've been talking about this!
Never underestimate the power of sealing a mechanical connection. Galvanic
cells need an electrolyte. Clean excess goo from the surfaces outside the
connection and seal them, like we've discussed for electrical connections.
Thanks for all the comments!
73, Kurt
YagiStress - The Ultimate Mechanical Design Software for Yagi's
Visit - http://freeyellow.com/members3/yagistress
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