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Saw Blades

The nearly ubiquitous reciprocating saw, otherwise known as a recip or demo saw, is handy in almost any construction and remodeling work. It helps remodelers take out the old before adding the new and, on occasion, is a superb pipe cutting device. But cutting masonry?

Most of us might think of standard carbide grit blades for only light masonry use, but that is changing now. With the assistance of some new blade styles, the venerable recip saw will cut masonry, such as cement block and some brick, almost like butter. It can also clean out mortar in a rush, making disassembly of some kinds of brick, block and other masonry walls or structures quick and relatively easy. Some of the heavy duty — and more costly — new blades can even tackle some kinds of stone.

Our own curiosity was piqued at this claim, so we gathered some Paws Off® Eliminator blades and a couple of chunks of medium-weight slate, and gave cutting a try with the blades chucked in a new Bosch R15 recip saw. (None of these blades, even the lighter duty ones, do well in cheap, consumer's grade reciprocating saws. After all, even light masonry is heavy work.)

With the #16 blade and 12-amp saw, we got reasonable speed and a decent looking cut. Some of the smoother grits should do a neater job, but at a slower pace. Using a reciprocating saw is not a rapid-cut method, though it's considerably faster than we expected. Like other types of masonry saw applications, you do need an absolutely solid method of holding the brick, block or stone. Handholding the material simply won't do.

The Grit Gets It Done
As you can see from the above photo comparing it to a DeWalt DW4843 carbide grit blade, the Paws Off blade is completely different structurally and uses a different abrasive to produce its cuts. It is different enough that Paws Off calls these blades "adaptors" rather than blades. Both blades work for many kinds of material that an ordinary recip saw blade won't touch. Compared to the much smaller grit on the DeWalt carbide blade, the Paws Off blade is a very heavy steel coated with tungsten carbide grit in a large flake form. The company says that both blades will work with many materials, including brick, block and some stone.

Due to these differences, it is unlikely that the DeWalt blades will last as long as the Paws Off blades, but you also need to consider the difference in price. The DW4843 carbide grit 8" blade can be purchased for about $12 for a pack of five. Meanwhile, the Paws Off Eliminator blade is not cheap: $29.99 is the MSRP.

The Eliminator blades work to cut concrete block, brick and some stone. They carry a promise on the sleeve to cut more than 100 brick, a promising number for a busy mason.

There are several other points on the Paws Off blades that make them much different from other carbide grit types. Variation in grit sizes is perhaps the largest difference. For instance, grit #16 does a rough cut job in a rush, while the much finer #24 provides a slightly smoother cut, albeit less quickly. Grits to #220 are available for those instances when a really smooth cut is necessary.

Another feature of the Eliminator blades is cooling slots in the bodies, varying in size with the grit. For example, the #16 grit has a single 2-3/8" long slot, while the #24 has four 1" long slots spaced along the blade's center.

Additionally, Paws Off blades can be used to rough — or finely sand, with grits over 80 — concrete, brick and other materials that normally are not sanded.

More information on Paws Off blades is available at www.flushcut.com.

European Know How
In Europe, many masons prefer to use reciprocating saws, or the more rugged alligator saw, over table or cut-off saws. One reason is due to the difference in materials, such as the widespread use of autoclaved aerated concrete (AAC) blocks and softer brick. Another reason is the difference in insulation installation techniques. For many European buildings, the veneer is installed, then a brick is removed from each wall section. Next, the insulation is blown in through the hole, and the brick is replaced and repointed.

Danish Tool Company currently has four types of tungsten carbide reciprocating blades — black, blue, pink and orange — specifically tailored for use with many different kinds of materials, from soft to hard masonry.

The black label saw blade is for use with softer materials, such as AAC block and soft stones, and sports cylindrical teeth (see page 27 for blade closeups). The blue blade also has the cylindrical teeth, but twice as many as the black blade, and can be used for soft stone, clay brick and mortar joints. The pink blade is also for clay brick and somewhat harder materials, but has more aggressive, positive-cutting teeth that cut through the material much faster.

Niels Mostrup, owner of Danish Tool, says the orange blade is the top blade, attacking the hardest materials that a person can throw at it.

"The orange blade is the Rolls Royce version of these blades. It has a lot more teeth and a special sharpening action," says Mostrup. "When you're using the orange blade, it's cutting during the Œpulling' action, but during the Œpush' action of the blade, the teeth are re-sharpened. Compared to the pink one, it's twice as fast, but you have less vibration. You can also use the blade in wood."

Each category of Danish Tool blades comes in a traditional reciprocating blade width of 3/4", ranging anywhere from 6" to 15-3/4" in length, and a monster 2" width, ranging from 12" to 17-3/4". The 25 combinations of Danish Tool recip blades available allow masons to choose the perfect blade for any task.

"The standard 3/4" height is useful when you want to cut out a single brick," explains Mostrup, "but if you, for instance, want to cut out an opening for a new door or window, the 2" high blade is very useful because it helps you keep a straight cutting line."

He also says that, while table and cut-off saws may remain a mainstay on U.S. construction sites, reciprocating saws have certain advantages that shouldn't be overlooked. First, masons only need one reciprocating saw, no matter what size blade is required. A simple switch of the blades quickly adapts the saw to any job. He also notes that reciprocating saws naturally direct dust away from the user, rather than "throwing the material around."

"I think probably the reciprocating saws are easier because you can stand at the exact construction area where you are building, measure the brick or block, and cut it off while you are there, instead of going over to a big table saw to do the work," he says. "Mason contractors and their crews will probably save quite a bit of time."

More information on Danish Tool Company products can be found at www.danishtoolshop.com.

Economical and Versatile
Representatives from LENOX of East Longmeadow, Mass. — manufacturers of the Master-Grit recip blades — also feel that reciprocating saws are a great alternative for masonry work. Reciprocating blades can be a welcome relief to the cost and care required for diamond blades.

"Typically, reciprocating blades are sold in multiple piece packs, around $10-15 for a two blade pack, unlike $100 and up for a single diamond blade," says Nick Morrisroe, director of marketing for LENOX power tool accessories.

He says that this price advantage allows masons to be able to focus on the job at hand, rather than focusing on pampering the tool. "If they go out on the job and are going to do cutting for the day," Morrisroe says, "they might use one blade one day and start with a new one the next, and they're only out $6."

Steve Hampton, engineering manager for LENOX reciprocating blades and linear edge products, agrees: "You need to take care to keep from fracturing the diamonds off of masonry table and cut-off saw blades. However, these blades are extremely robust, designed for a robust machine, and they don't need to be babied in any way."

Reciprocating blades can also do things with masonry that you can only dream of completing with other saws.

"The blade is designed for spring back, so you can actually bend the blade while you're cutting," explains John Sullivan, senior product manager for LENOX reciprocating blades and linear edge products. "I know that's totally different than what people are used to with other types of saws. Flush and plunge cuts are also possible, which is relatively impractical with other saws."

Available in 6", 8" and 10" lengths, the Master-Grit blades consist of a single-layer of grit that can cut through hard, abrasive materials.

"The harder the material is, the better. That's actually what that blade is designed for," Sullivan explains. "Not that you can't cut soft materials with these blades, but the softer materials tend to gum up and make the blade a little less effective."

Hampton adds that the blade's abilities to slice through hard brick, block and stone come down to the materials used in manufacturing the Master-Grit product.

"The blade has a very high-strength, resilient backing steel — it's the same steel that we use on the LENOX band saw blades," he says. "Meanwhile, the 400-600 micron carbide grit is held in place on the blade with a high-temperature silver alloy braising compound."

While the blade is rough and tough, there are certain ways to get the most out of a reciprocating saw when cutting masonry.

"There are typically two settings on a reciprocating saw: straight mode and orbital mode," says Sullivan. "You really want to use the straight mode when you're cutting, because of the fact that it's an abrasive you're going to get more efficiency. The blade is going to be cutting both on the stroke forward and the stroke back. In an orbital mode setting, it wouldn't be as efficient."

The LENOX team also suggests starting the blade slowly — taking advantage of the variable-speed trigger that most saws utilize — and at an angle, so that the blade can grab the material and get its momentum going. Once the blade is completely engaged, then the user can increase to a faster speed. They also suggest gently rocking the saw to assist in removing dust and debris, and when necessary applying water as a coolant.

Finally, the team stresses that picking the appropriate blade length is very important, using a blade that is as close to being 2" longer than the material being cut.

"You want to use as short of a blade as you can to prevent a lot of the whipping," says Morrisroe. "So if you're cutting through a 3" or 4" piece of material, you probably want a 6" blade; if you're cutting though a 5" piece of material, you probably want an 8" blade. But you don't want to use a 10" blade on a 2" piece of material because you'll have a lot of whipping and other problems."

Visit www.lenoxsaw.com for more information on Master-Grit blades.

Safety First
The Bosch Power Tools and Accessories division of the Robert Bosch Tool Corporation in Mount Prospect, Ill., also offers two tungsten carbide grit coated blades for cast iron and block that are 6" and 9" long. According to Steve Angus, Bosch Accessories group product manager - linear edge, these recip blades utilize a 30 tungsten carbide grit, which is baked onto the blades edge, and are best for cutting all types of abrasive materials, such as cement block and bricks.

"Bosch has focused on color coding and labeling its blades so users are sure to select the appropriate blade every time," says Angus. "Always use the correct blade for the application."

Although recip saws may create less dust hazards than their counterparts, Angus still encourages users to be prepared, wearing safety glasses and a mask for protection.

For more information about the Bosch cast iron and block recip blades, visit www.boschtools.com.

While all of the experts we spoke with feel that recip saws have certain advantages over other types of masonry saws, none of them hesitated in acknowledging that recips are not going to be the answer to every cutting need in the North American market.

"They're not meant to be a continuous-use blade," explains Jason Feldner, public relations manager for Bosch Power Tools and Accessories. "What these blades really are is an alternative, a quick cut."







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