Hi, all. Building my launcher, a friend gave me some pipe for the combustion chamber that he didn't need. I just found out that it is probably this stuff:

http://www.lowes.com/pd_23837-1814-PVC+04300++1000_0__?productId=3133047&Ntt=pvc+3%22&pl=1&currentURL=%3FNtt%3Dpvc%2B3%2522&facetInfo=

Is says ...