Keeping sand and water warm when mixing mortar in cold weather is an age-old problem for masons. The traditional solutions of heating sand and water directly over open fires or over culvert pipes with fires in them leave room for improvement. Three products now offer practical solutions to these problems. One device is a giant electric heating pad for the sandpile; a second heats water in a drum that then works like a hot water bottle to heat the sand; and the third heats water in a chamber and releases steam to heat the sand. HEATING PAD The pad works like an electric blanket. According to the manufacturer, the pad produces constant heat and is inexpensive and simple to operate. To use the pad, lay it on top of the sandpile and place a tarp over it. Plug in the pad and let it heat overnight. ELECTRIC ROD Like the heating pad, this device eliminates unsafe open fires. Unlike the pad, it warms both sand and water. It works by heating water in a steel drum buried in the center of a sandpile. Heat from the water radiates through the drum to warm the sand. STEAM MACHINE This machine uses a 25-gallon steam chamber and 200,000-Btu liquid-propane torch to warm a truckload of sand (22 tons), from top to bottom, in about 4 hours. According to the manufacturer, the machine generates a full head of steam in 35 minutes from a cold start.