A dead blow hammer is a type of mallet designed to deliver strong blows with minimal rebound. The head of a dead blow mallet is hollow and filled with sand or shot. Because of this, the force delivered by each strike is spread over a greater amount of time, thus reducing rebound while minimizing damage to the target surface.
Think of it this way – as the mallet is swung towards its target, the shot in the head cavity will collect towards the opposite side in the head similar to how one can “fall up” in a dropping elevator. At the instant the mallet strikes its target, the shot is projected towards the target-side of the head. Whereas a rubber mallet would rebound away from the target at this instant, a dead blow continues to deliver an additional force.
A dead blow is well suited for many assembly and removal applications. While most common dead blows have a non-marring plastic casing, there are many other styles available – dead blow ball peins, for example.
Good pro-quality dead blows hammers are typically priced at about $1-$2 per ounce, but we’ve seen certain brands go for much more, and of course you can find many non-pro versions for less.