Masonry Magazine July 2006 Page. 42
CLEANING EQUIPMENT
"It is important to keep the nozzle at a greater distance from the work area so that you do not cut into the masonry or destroy the integrity of the masonry joint." Matt Hoefer, Mi-T-M
helps you meet tight deadlines. A more subtle benefit of an automated solution is the higher consistency achieved when all or a large part of the job is done at once, rather than over many days, and when the operator can focus on the quality of the work rather than an aching back."
Worker Fatigue
ERGONOMICS and operator fatigue problems shouldn't be overlooked, agreed Lynn Peden, owner of EaCo Chem of Forestville, Pa. EaCo Chem focuses on brushless chemical cleaners for new and restoration masonry work.
"The biggest problem with pressure washers isn't the pressure (psi) but the operator training," Peden said. "If the operator uses too much water on the job, that is both wasteful of the water and stressful for the worker. While some people claim you should use a maximum of 500-700 psi with the pressure washer, that's only one factor in the equation."
Peden uses a formula for determining the best combination of pressure and nozzle that results in a unit proper for the work at hand. "The formula is simply gallons/minute times psi equals cleaning units (CU). So if you have a 2,000 psi washer and use a four-gallon/minute nozzle, the CU is 8,000. That should be good for most masonry cleaning. When you are done, however, the rinse cycle, as it were, does require a higher pressure wash. Here, high psi comes in handy to wash out chemicals using a five- to seven-gallon/minute nozzle."
Whoa, says Hoefer of Mi-T-M. "The general rule of thumb when cleaning masonry is that psi is more important than gpm (gallons per minute). We would recommend at least 1,500-2,000 psi. Higher psi can be used, but it is important to keep the nozzle at a greater distance from the work area so that you do not cut into the masonry or destroy the integrity of the masonry joint. Start with a 40-degree tip, which is the widest of the spray pattern. As you get a feel for it, you may be able to go to a 25-degree tip for a deeper cleaning."
If you attend Masonry Showcase or any of the other masonry trade shows, you've most likely seen Prosoco's booth and met Gary Henry, Prosoco's business communications specialist.
"One of the big problems that contractors run into in the field is inexperienced workers using too much pressure to pre-wet and rinse masonry walls," Henry said. "They'll take a pressure washer on a new masonry wall trying to knock the excess mortar off. They'll hit it with 3,000 psi sometimes, and get right up close on it. That leaves wand marks all over the wall that won't come off and it blows out mortar joints. That is a terrible problem: people using too much pressure and not enough water to rinse walls."
Not so fast, said Diedrich. "The nice way to do this is about five gallons a minute at 1,000 psi. That's what I used to use 36 years ago. Never did any damage and was easier to work with. It was great."
He added, "A lot of this has to do with nozzle tips. Pressure washer users are demanding faster, bigger, more efficient systems. Now everybody is looking into oscillating tips, which are like machine gunning the dirt or paint off. It looks like a nor
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