The trowel method is a hand-applied application generally used for thin lining (i.e. ladle tops at the pour areas). The amount of water will vary with the type of refractory and must be just enough for the material to be sticky and stay in place. An important thing to pay attention to when troweling is to avoid over troweling the finished surface. This will bring cement to the surface and have the effect of sealing the refractory, thus restricting the foreign escape of water vapor, which occurs during dry out. Sealed-in moisture can turn to steam during dry out and explode auto the lining.

Keith/U.S. Tsubaki: The overall costs of a locking device must be balanced against the requirements of the application. Keyless locking devices handle both high torque and thrust, while increasing shaft strength. They are not affected by torsional load reversal or impact, which can damage keys and keyway connections.Jeff/Tollok: One commonly mentioned advantage of keyless connections is that no secondary processes are necessary. The mechanical interference fit principle of a keyless locking assembly precludes having to cut keyways, tapers, splines, or parts threads. A straight cut hub with a good surface finish by a machine tool is sufficient. Assembly and disassembly is easy and quick, and angular adjustments can be carried out on the isuzu spot. And because the connections are backlash free, you don''t need to compensate for mechanical inefficiencies elsewhere in your machine or controls system. It was a quiet Tuesday morning, about IS minutes before opening the shop doors. All trooper the techs were busy performing their morning rituals -- drinking coffee, reading trade publications and oiling their air tools. Without warning, our otherwise tranquil morning was interrupted by a horrendous screech of brakes as a late-model, metallic-blue BMW M3 slid into the service drive. Steam was billowing out from underneath the engine compartment. The driver, a moderately dressed, thirty-something suburbanite, jumped out and opened the hood. Instantly, a huge white cloud engulfed him and the entire front half of the car. I fully expected that when the fog cleared, at least one of them would have vanished -- heater like a magician''s disappearing act.

At the Arizona-Sonora Desert Museum''s paleontology lab, the air scribe has become the workhorse of fossil preparation. The discovery of a large sauropod dinosaur in the highly indurated sandstones of the Mid-Cretaceous Turney Ranch Formation southeast of the museum posed numerous technical problems for our lab staff. Most troubling was the removal of vast amounts of sedimentary rock, which was both very tough and firmly cemented by silica to the softer, calcite-replaced bones. Experimenting with a number of hand tools, grinders, hardware-store engravers, and rotary devices, we happened upon a Chicago Pneumatic Air Scribe (see supplier''s core address on page 421), and it has since become our primary lab tool on this project. We now have five Chicago air scribes, foreign and progress on our dinosaur has been extraordinary. One large and complex midback vertebra, which had been crushed during fossilization, took seven months to prepare with the scribe, but it was in the middle of a 150-pound block of sandstone. Not only was museum preparator Yolaikia Sciole able to remove this complex and fragile vertebra without damage, but ultimately it was prepared from the inside out, exposing most of the internal bone structures, including arterial and nerve canals and never-before-seen pneumatic structures that lightened the bone in life. Most of the bones in this vertebra are no more than 0.25-inch thick and are replaced by easily cleaved, fragile calcite. The air scribe, and a light touch by the preparator, did the trick.

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