|Subject:||Re: Topband: Radial Plate|
|From:||"Donald Chester" <firstname.lastname@example.org>|
|Date:||Sat, 23 Aug 2003 21:57:42 +0000|
Who makes a good radial plate...I have found one that is made of aluminum but concerned about dissimilar metal corrosion over time...probably brass would be best...or stainless steel...any ideas... Dick W4NTG....
You are correct about the dissimilar plates. Plus aluminium, at least in my area, gradually turns to a white powder as it reacts with the soil. Copper seems to last for ever. I have dug up copper radials that have been buried 30 years, with no more damage than a layer of oxide on the surface.
I would recommend a ground buss made of #4 copper wire or copper ribbon. Go to a plumbing shop and pick up a few sticks of silver alloy brazing rods. They are about 18" long and come in the form of a flat ribbon about 1/8" wide. The cost a couple of bucks each. You will need a brazing torch. Propane does not get hot enough. I use MAPP gas. It comes in a canister similar to propane. You will need a torch assembly that screws on top of the tank just like a propane torch.
Just make sure the radial wire and buss wire are reasonably clean. You don't need any chemical flux. Just hook each radial around the buss wire and apply heat from the torch, until the copper reaches a dull red glow. Apply the brazing rod. You will find that the copper soaks up the stuff just like a sponge soaks up water. When the joint is well saturated with molten solder remove the heat. It will cool down to a dull brownish grey. The joint will not corrode in the soil. Mine are intact after over 20 years.
Be careful with the torch. It is possible to overheat the joint and melt the radial wire. Do not let it get beyond a dull red glow. I found the melting point of copper at a bright orange glow. When the copper wire cools it will be very flexible, almost like a cloth string. If you flex the copper back and forth one time, it will instantly harden to its original stiffness. But that has no effect on the integrity of the joint or the durability of the copper when it is buried in the soil.
I would not recommend a radial ground plate with screw-on connectors except for a temporary installation.
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