Before we get into pipe jumping, I think I'd better quickly mention how you can detonate pipebombs. Remember that, although the standard mode for the Demoman is regular grenades (impluse 6), he has the ability to lob pipebombs (impulse 7), that can detonate whenever the player wants them to. To bind a key to the command, simply select a particular key, and then type the following in the console:

> bind <key you've chosen> "detpipe" (Don't include the "<" and ">" in the actual string)

Personally, I find it easiest to use a key that's close to my firing button to detonate my pipe bombs. My firing key is Ctrl, and my detonating key is s. In this way, I can fire and detonate my pipes by using the same hand. For those who have a three-bottom mouse, a good idea would be to bind one of the buttons to detpipe.

Pipe Jumping is a technique that I don't use very often, because it damages the Demoman so much; much more than a rocket jump does for a Soldier. However, it is a very useful thing to be able to do if you're on offense and you want to try to grab the enemy flag quicker. There are many places where you can PJ, but we'll use 2fort5 as an example because it is played so damn much.

The Grate

If you haven't realized it already, one of the places in 2fort5 where there's always at least one enemy is in their main lobby - the room with the two ramps? Anyway, a great way to skip that part of the level is to PJ the Grate. It is the area just inside the main entrance to the base. The idea with PJing is that you lay a single pipebomb on the ground, and then run at it, and you pull the trigger right when you're on top of it. At the same time, you jump, and you'll go flying up, just as high as a Soldier does when they rocket jump. Here are two pictures that show you where to place the bomb when you want to PJ the grate:

click on the pictures for a larger image

Look down a bit, and place it... | ...right beneath the grate

The Battlements

Another great place to PJ is the battlements. PJing here will bring you right up to where those pesky snipers are (God, I hate 'em sometimes) Again, the idea is to run over your pipebomb, and then jump and pull the trigger at the same time. This will propel you upwards, and then all you have to do is walk forward once you get level to the battlements. Easy as that.

click on the pictures for a larger image

Put it right next to the ramp | Launch yourself up there and frag those snipers!

The Elevator Shaft

As I mentioned in the MIRVs & grens section, it is possible to pipe jump your way up the enemy elevator shaft, as opposed to using a primed hand grenade or simply going up the spirals as most people would. However, unlike places such as the battlements and the grate, the elevator shaft is too high to get up by using only on pipebomb - you have to use two. Simply place two pipebombs at the bottom of the shaft, and then run over them, jump and pull the trigger. You'll go flying straight up and out the shaft (make sure you're still running forward as you go up). Unfortunately, two pipebombs do hurt, so chances are you won't have enough health to do this kind of a jump too often, but it is useful on other maps.

One Final Note

Pipe jumping is, of course, not limited to 2fort5. There are many maps out there that have excellent places for pipe jumping. Search them out and give things a try - be creative! A good way to practice pipe jumping is to find a private server (or a deserted public one) and try these jumping strategies on your own. Then, when you join a real game, you can try them out in real combat situations.