Actually, the Longhorn was invented by Frank Van Alstine and is avalible from his website for free in the Audio Basics section, 1982 back issue set, page 8-9, (April). This fully describes the materials needed and how to make and damp everything. You need 4 things, 1000 centi-stoke liquid silicone, K&S #181 1/8" brass U-channel, Plasticlay and some 2 part bonder or epoxy.
Wayner aa