A tamp, also called a tamper, is a tool used to compact granular matter such as crushed stone, dirt, sand, or cinders. This tool is very often used in the preparation phases before paving or pouring concrete, and it helps prevent the supporting materials from becoming too porous to support the heavier paving or concrete materials. Two general tamp varieties exist: handheld tampers and power tampers. Most small jobs can be accomplished with the handheld variety, whereas larger paving or concrete jobs will require a power tamper to adequately compact material over a large area.
The general structure of a handheld tamp is quite simple: a long, often wooden handle is affixed to a broad metal face. This face is usually very heavy and made of steel or iron. The specific size of the face can vary according to the overall size and intended use of the tool, but it is usually small enough to be wielded easily by one person. The user will stand with the tool in front of him and grasp the handle with both hands. After raising the tool above the ground, the user can force the tamp back down to the ground, pressing the face with force against the materials to be compressed. This motion will need to be repeated several times in the same spot or over a wide swath of materials for effective compression.
A power tamp accomplishes the same goal, but with more force and usually a much larger tamping face. The user will not be required to pick up the tool, however, as he or she must do with the hand tamp. Instead, A motor is mounted to the power machine, and it actuates a piston that will rapidly raise and lower the tamping face. This tool is exceptionally heavy and may, in some cases, need to be operated by more than one user for stability and safety. The size of the tamping face can vary according to the intended use of the power tamp; some models are quite narrow and are used for tamping material in narrow trenches, while others can be very wide and used for compressing larger swaths of material.
Most power tampers run on gasoline, and they can be exceptionally noisy and difficult to maneuver. Hand tampers are fairly lightweight and easy to use, and they require no additional users to operate safely and effectively. They are also quite a bit less expensive than power tampers, though power versions can be rented on an hourly or daily basis for a low rate.