The boom is 1/2 X 3/4" wood.  The elements are 1/8" diameter and have been made from Silicon Bronze welding rod, Aluminum rod, Hobby tubing, and solid ground wire. You really want to solder to the Driven Element. Silicon Bronze Welding rod, Hobby tubing, and #10 or #12 solid copper wire have been used to make the driven element.  A drop of "Super Glue", Epoxy, or RTV is used to hold the elements in place.