"Spike" wrote
2. How do I bond the radials together? (I guess my 15-watt soldering
iron won't be up to the job ...).

Use a car battery clamp and plenty of grease.

Never, ever use "Grease" (or any other lubricant/protectant) in an
electrical connection for RF. Grease is a dialectric (so is silicone) and it
will ensure you have practically no electrical connection at all.

There are copper and other metal-alloy pastes available for making
mechanical lightning protection and RF connections. They are the only thing
that should ever be used to make up mechanical joints. If you don't have
them, make the joints dry and leave them that way. Copper oxide (normally
green) that forms outside of bare copper from oxidation is conductive and
causes very little difference in conductivity. Aluminum oxides and carbon
steel rust are not very conductive, although not much different than poor
soil that most radials are buried in.

Jack Painter
Virginia Beach, Virginia