Can I tape up some cut in half aluminum cans and use them for a reflector? I have an 3 18" floro bulbs but I don't have a reflector and would like to make one.
You could. Or, you could get some smooth venting pipe from Home Depot, Ace, etc it is a long piece of curved aluminum that is designed to fit together with another piece to make a tube/pipe, just use one piece that has a semicircle curve.