One of the things you have to avoid in Project Zomboid is getting swarmed by zombies. Once you are surrounded by zombies, you are pretty much a goner. However, the addition of the Pipe Bomb can help you fight back against a horde of zombies.
Pipe Bomb Guide — Project Zomboid
When you are in the overworld, fighting zombies can require powerful melee weapons or guns. However, guns require limited ammo, and finding them can be difficult.
Not all guns are effective at defeating a horde of zombies either. On the other hand, if you have an Engineer on your team, you might want to invest in a Pipe Bomb.
Pipe Bombs are throwables that can attract zombies and damage zombies in a 7-tile radius.
The Pipe Bomb is powerful and can leave a burning effect on the area as well. However, you can only craft it if you are an engineer. There are no books on the map that can teach you how to craft a Pipe Bomb.
To craft a Pipe Bomb, you need 3 Scrap Electronics, 1 Metal Pipe, 20 units of Gunpowder, 1 unit of Twine, and a Saw. You will also need a recipe magazine and duct tape to craft it completely.
NOTE: You may attach a timer, a motion sensor, or trigger to the bomb.
Hope this helps you in fighting the horde of zombies!
ALSO READ: Project Zomboid: Dungeons Guide