There is a certain way to stylize boffers to give them an edge. This makes them slightly less safe, but if you're good about it there should be few problems.

Usually, when you make a boffers, you'll slide the foam over the PVC pipe. This will result in a round stick, not unlike a baseball bat. To get a more realistic edged weapon, here's what you'll want to do.

You'll need the following supplies:

-knife
-electrical tape, flash tape, or some other narrow marking tape
-other supplies for making your boffers

Instead of sliding the foam over the pipe as you'd normally do, cut the foam in half so you have two separate half-pipes. Then reverse them; so instead of the foam looking like this: () you have the foam looking like this: )(.

Now find a way (this will require some dexterity on your part) to tape the foam back together so it's inside out. This way, the foam will not be round; instead, it will be shaped somewhat like the human eye. Make sure the edges of the foam are held together snugly and tightly by the duct tape. Now slide the pipe in and complete your boffer as necessary.

It's a good idea to mark the new "edges" of your boffers with flash tape or electrical tape to denote the actual blade of your weapon. To make a point on your weapon, just cut the corners of your weapon and tape over it. This results in a point that you'll want to be careful with around someone's eyes.

This would be a good idea to use for:

-swords of all kinds. This should be obvious.
-polearms, such as a yari or spear. Just make a polearm with a long blade on the end.
-javelins. This can be done by using lighter pipe, though throwing boffers isn't always a good idea unless they're really, really, really safe. I mean, really.

The trick is being safe with these weapons - the tip is easier to put in someone's eye; also, the inside of the foam isn't as soft as the outside. Additionally, the blades of a weapon may collapse inward and, depending on how well-made your boffers are, may have less foam and therefore cause more damage.

In other words, this is a technique that should be reserved for more experienced builders of boffers.