Although this'll be a small section, it is very important when convincing unsecure parents that this home built contraption WON'T blow off yer arm.
Prettymuch the main safety quarrel is between the use of PVC and ABS pipe. Well here are the facts, plain and simple.
Another safety issue are the glue joints. This will not be a problem so long as you follow the instructions and don't go changing anything "major." 99% of the time however, properly glued joints (with the proper glue) will never blow off.
The same deal applies with the igniter. If the epoxy is applied properly and no air holes are left, than the chance of the igniter being blown off is just as unlikely
Also, I have designed a safety addition for yer spudlauncher. Folow the link below to check it out. It's just a little bit of reassurance, not that anything is gonna go wrong or anything
More stuff on tips coming soon...so hold on =]