http://www.mcmaster.com/
A scientific and industrial supply company. For instance, you pay $19.95 for a 6"x6" sorbothane sheet at Music Direct; at McMaster's you pay $15.90 for a 12"x12" sheet! About 40% of the price of MD! Plus, they all kinds of sizes and thicknesses that you won't find on audiophile sites. This is just the tip of the iceberg- name the raw material or machined item and they will probably have it. 
http://www.mcmaster.com/
A scientific and industrial supply company. For instance, you pay $19.95 for a 6"x6" sorbothane sheet at Music Direct; at McMaster's you pay $15.90 for a 12"x12" sheet! About 40% of the price of MD! Plus, they all kinds of sizes and thicknesses that you won't find on audiophile sites. This is just the tip of the iceberg- name the raw material or machined item and they will probably have it.