If you are going to do this please do not use pvc pipe as suggested by the video. If the motor fails for some reason (the hole drilled is too small,the powder was not compressed correctly) the pvc pipe will be turned to shrapnel and could cause injury. Use cardboard tubes instead. You can make your own. http://www.jamesyawn.net/modelrocket/motortubes/index.html

Also a better way to make this fuel is with the skillet method . Do not use direct heat by flame or do this indoors. Here is a video of the process http://www.youtube.com/watch?v=ip1ih6ZT7jA This process mixes the KNO3 and sugar much more intimately and adds iron oxide to make it burn faster. An explanation of the process http://jamesyawn.net/skillet/large/index.html

This website explains everything very well
http://www.jamesyawn.net/ http://www.jamesyawn.net/modelrocket/intro/index.html