"We get blades back all the time that are fried because water wasn't used," Fisher says. "It doesn't take very long for the friction of concrete (or even asphalt) to burn up a blade."
Smith was in a rental yard when a customer returned in less than an hour. The customer was using a wet blade to cut cured concrete but he was cutting dry. He nearly destroyed a diamond blade, and both he and the rental store owner were unhappy.
Don't bury the blade.
Another common mistake is burying the blade all the way to the flange, or forcing the blade through the material being cut.
Forcing the blade through the material will damage the saw by increasing the amperage, burning up the motor and overheating the blade, which causes premature wear and damage, explains Skaff, who has seen blades burned so badly they have a purple rainbow around the rim.
Metal in the diamond rim can get so hot that it covers the diamonds. Glazing over diamonds on the rim can cause blades to dull and stop cutting even though there's a lot of life left on the diamond rim of the blade, he continues, noting this can be solved in the field by dressing the blade.
"You always want to let the blade do the cutting, whether you're using a handsaw, stationary saw or walk-behind saw," he says. "That will increase the life of the blade and the life of the tool being rented."
Fisher adds, "In reality, you shouldn't even use half of the diameter of a blade." Instead, he says you want to make several passes with the blade.
In other words, Smith says, customers need to be using a step-cutting technique.
Don't be pushy.
No one likes to be pushed beyond his or her limits, the same is true of tools and blades. A customer should not push a blade too hard just to get a job done fast.
Don't spin in the wrong direction.
Often renters will spin a blade in the wrong direction. Arrows labeled on the blade show the right direction to put the blade on a saw. Blades need to be installed and spin the way the directional arrow is pointing.
A blade will still cut if it's spinning the wrong way, but the diamonds will be eaten up quickly, Fisher says.
Do remember the drive-behind pinhole.
When mounting blades to walk-behind saws, Fisher says not to forget the drive-behind pinhole. In addition to the center arbor, he says that the second hole on the flange steadies the blade and prevents wobbling.
Do use caution when changing directions.
Skaff offers another word of caution for walk-behind saws: "If your blade is an inch deep into a cut and you want to turn, don't rotate the saw while the blade is still in the cut," he says. "I've seen segments of blade bend and break because a machine changes directions while the blade is still in the cut."
He adds, "If you're going to change directions, make sure your machine is off and the blade is up out of the cut and the machine is unplugged."
Final words of advice
Manufacturers offer manuals that cover diamond blade basics (how to use water, how to mount blades, how fast to spin blades, how to determine the proper size saw for the proper blade). Make sure customers have access to all the information they need to operate efficiently - and of course, safely.
If a customer destroys a blade, he usually is responsible for paying for it, and he's not going to be happy.
"You want to keep your customers coming back," Smith says. "If you can identify the material they're cutting, the operator's expertise, and educate renters about the basics, then everyone is happy."