Topband: Soldering ground radials

[Charles Bibb]

Hi, fellow topbanders,

(Only) in the past couple of years, I've been reading in several 
authoritative texts on low band DXing how we should not be using the 
traditional Lead/Tin alloy solder to bond any connection that will be 
exposed to the soil. Supposedly, the acidity of the soil will dissolve the 
solder joint over time.

I have a few questions about this, like:  Is it really true?  And, if so, 
how long does it take?

After reading the warning, I went into the yard and checked some of the 
solder joints in my radial system (mostly where the individual radials are 
joined to a common annular ring at the base of the vertical). Some of these 
joints are nearly ten years old, and I can find not the slightest 
degradation of the Pb/Sn 60/40 solder, only a dulling of the surface. My 
radial system was installed on top of the ground with wire "staples" and 
has since buried itself under the grass roots. Also, my soil is slightly 
acidic. Does the soil need to be highly acidic for the solder joints to go bad?

Would the "lead free" solder used for sweating copper water pipes together 
be a better choice?  Which alloys are the most resistant to the effects of 
the soil?

I'd like to hear of the experiences of others with radial-wire solder 
joints in the soil.

Charles - K5ZK