I built mine from copper fittings. Its not pretty but it works well. It will suck up my methodoxide from the floor to about 5 1/2 feet where the venturi is. Here is an article that I used to build it
vegetableoildiesel.co.uk - Easy 15 minute venturi for GL processor - Powered by XMB

the sizes are metric but 3/8, 1/2 and 3/4 copper works too