Step 4: Gluing The PVC
The glue really stinks, is very flammable, and will cause numerous health defects and possibly death merely by working with it. Not really, but its nasty stuff. As you can see in the first image, I'm working outside, because the glue causes headaches and cancer (not really), on my dad's planting bench. I've put down an old piece of plywood, which I covered with about 10 sheets of newspaper. You're going to spill the primer and glue, and you don't want to mess up something important.
You will probably also want to have a large grip pliers, such as the channel-lock pliers I have here. They will help you grip pipes and fittings, and it's much easier to wipe glue off the pliers than your fingers. I'll point out that when you are test fitting your fittings together, they will feel really tight, like you can't get them in all the way. When you get the primer and glue on the pieces, they will slide together like butter. Don't worry about that, but be sure not to cut your pipe too short, as you'll be able to slide it in further with the glue on it than you could while it was dry.
You might not want to glue all the fittings, as someday you might want to get them apart. In the case of breakage, you'll appreciate having a modular design, so you can replace just the broken parts. My first cannon fell off a table at a science fair, breaking the connections to the valve, which was glued on. The valve is perfectly fine, sitting in the corner of my room on the floor, but with broken off connections glued into it, it's pretty much worthless to me now.
As to the actual gluing process, here's what I do. I've received no formal training on PVC gluing, but this is what seemed to work. Don't forget to sand your connections as per the previous step. I take the purple primer brush and wipe it all around the connection area, where the bond will be made. Do this on both parts to be glued. Wait a few seconds, then take the actual glue. Spread it over the same area as the primer, and quickly set the brush back in the can. Take both pieces, and slide them together. It's pretty cool how easily they fit together when properly lubricated. Take your paper towel or rag and wipe off any excess you see, be sure to check inside, too.
As for the drying / curing time, I have always left the pieces for at least overnight, sometimes 24 hours. For this particular project, I left the pieces on the bench (they smelled bad) overnight until about 12:00 the next morning.