One of the more important aspects of Red Faction 3 is using the right weapons for the right situations. Not every situation calls for a Rocket Launcher or Remote Detonator. Sometimes a simple whack of a hammer can go a long ways.
When trying to take down buildings, sometimes efficiency overrides expedience. Yeah the EDF is breathing down your neck, but rushing through a building demolition is only gonna get you killed that much faster. Keep in mind, the hammer is an EXTREMELY useful ammo saver and demolishing tool. You can really tear apart a building with this thing. When a building is weak enough from your hammer, then you wanna start placing charges to bring it the rest of the way down. This way you use less charges, and you get to blow up more stuff.
Another useful tool you will get access too when you hit the Badlands is the Nanomachine Rifle. Save up 700 scrap for that bad boy. It is a great weapon all around. When you upgrade it fully, it will be a force to be reckoned with. It basically disintegrates a given area or target. And it leaves the scrap behind. This is a great door opener or turret killer, or anything killer. But be warned, even with the ammo upgraded, it doesn't have a whole lot. But its enough to have a lot of fun with.
The Arc Welder has plenty of practical uses. It is an electricity based weapon and it does things you would expect electricity to do. Say, all those guys are standing on a metal surface. Why don't ya shoot the metal surface instead of them, and see what happens?
Also, if you need to steal a vehicle, like those in the various convoy missions, the Arc Welder kills anyone inside a vehicle so you can push the dead carcasses out of the way and drive on. (Remember one of the adverts in the Robocop movies?)
Keep in mind that the weapons don't always have a straightforward use for them.