Joints should be sawed in concrete slabs before drying or cooling causes random cracking. But timing can be a problem with conventional saws. A recently developed saw solves the timing problem by permitting joints to be cut as soon as the surface is dry to the touch. The lightweight saw is made of aluminum and stainless steel. Weighing about 24 pounds, it's powered by a 2-hp, 13-amp electric motor. A specially made 5-inch-diameter diamond blade housed in the unit makes the cuts. The blade is thinner and its speed is faster than that for conventional saws.


Because it's light, the saw can run on newly placed concrete without marring the surface. A sighting guide helps the operator match the cut to the line, and an extension handle lets him cut up to 30 feet away. Maximum cut depth is 7/8-inch at the slowest speed. A color-coded depth gauge at the front of the unit shows the operator how deep he's cutting. There is no cleanup after cutting. Dustlike material that the blade pushes to the surface doesn't stick and blows away when it dries.