[TowerTalk] Radials

Donald Chester k4kyv at hotmail.com
Mon Aug 21 22:09:30 EDT 2006

I would beware of any kind of connection that depends on mechanical pressure 
for contact, especially if the  bus ring is buried in the  ground.  If 
soldered, you must use brazing material like silver alloy.  I once used 
plain old lead/tin solder, and had to go out and resolder all the radials 
every 2-3 weeks.  The chemicals in the soil decomposed the solder and it 
turned to a white powder, and the radials just fell off the  ring.

My present setup used silver alloy brazing rods, installed about 25 years 
ago.  I just dug down to the bus ring a couple of weeks ago to inspect.  The 
brazed connections are all still intact.

I purchased my brazing rods  from a plumbing supplier.  It has  long been a 
violation of  code to use  lead/tin solder for copper pipes because the lead 
in the solder may leach into drinking water, and lead solder deteriorates 
just like it did with my radial system, and the pipes eventually leak.  The 
codes require a special silver solder sold  for the purpose.  The rods come 
in about 18" lengths, flat stock, about 1/8" wide.  It takes a hot torch to 
reach the melting point of the solder.  Ordinary propane won't do it, but a 
Mapp Gas torch works very well.  The copper must be heated to a dull red.  
No flux is needed, and the copper need only be cleaned well enough to get 
rid of any scaling oxide on the surface.  Once the alloy melts, copper soaks 
it up like a sponge soaks up water.  The rods aren't cheap, but not 
outrageously expensive either.

Don k4kyv

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