[TowerTalk] Fwd: Fwd: Screw Anchor Experience

[K0DAN]

Hans is right.

You need an intermediate metal for washer, lugs , or other hardware.

If your installation is only for Field Day, or a few months/years, it 
probably doesn't matter. If you want your installation to be "forever", then 
this stuff has some bearing.

In the long term if you have dissimilar metals (eg galvanized/iron/steel 
mixed with copper/brass) you will sooner or later have battery effect 
(galvanic action). Depends on pH of all materials, moisture, etc. I don't 
have much expertise in the chemical arena, and we need our C.E.'s to weigh 
in.

One tip I was given is to use a "mediator" metal to join two reactive 
dissimilar metals (similar to "sacrificial anode").

In many cases this means joining
a) Galvanized steel tower
b) Copper/brass wires/clamps/rods

The trick I learned (unconfirmed but maybe True?) is to use STAINLESS STEEL 
hardware (someone else said lead, also fairly non-reactive) to keep the 
iron/steel separate from copper.

So:
Galvanized steel tower legs to
Galvanized tower base to rebar, concrete, whatever
Big galvanized tower bolt thru base with galvanized  lock washer & nuts on 
the other side
For grounding, a number of big fat 2"+ diameter stainless steel washers on 
other side, enclosing copper ground wire which ONLY touches & is bonded to 
the stainless (might require copper lugs, etc.). While all metals are at 0 
ohms what we are looking at differences in metals
Key issue to keep copper ground wire 100% in contact with the stainless 
steel, but no other metals, not soil, not concrete, etc.
If you can achieve this (not easy) you will have minimal (but not zero) 
etching of metals

Not sure this makes sense, but it's what I now do and so far seems to work 
well.

73
dan
k0dan



-----Original Message----- 
From: Hans Hammarquist
Sent: June 20, 2013 17:09
To: towertalk at contesting.com
Subject: [TowerTalk] Fwd: Fwd: Screw Anchor Experience

To connect an anchor to a copper ground rod is an absolute no-no. That will 
"eat" the anchor in no time.


Old wisdom (my grandfather, that was a blacksmith) to me to use a lead 
washer to minimize electrolytic corrosion. I put small pieces of insulators 
between the anchor rods and the turnbuckles to interrupt possible current. 
Could not harm, I believe.


Hans - N2JFS