Masonry has been around for thousands of years. The last 80 years, however, have seen the greatest innovations in the trade. In this part of the article, we will now focus on the Masonry saws and blades.
History of Wet Cutting
In 1926, a blade was invented that could cut stone, brick, and concrete masonry materials. The cutting or grinding was possible by using diamond grit or chips embedded in a metal matrix creating the segment. These segments were brazed/welded to a steel core and completed the blade. Diamond blades, as they were called, were used in factories on very large specialty machines. At the time, there were no practical applications for use on a jobsite.
That changed in 1936 with the invention of the Clipper Electric Masonry Saw. This new saw, coupled with the diamond blade, changed the way masonry materials could be cut on jobsites and it started to replace the trusted hammer and chisel for cutting. Over the next 40 years, several manufacturers jumped into the masonry saw business. They created similar stationary masonry saws that could also be used on jobsites. These new masonry saws became widely used in the 50’s and 60’s, especially as electric versions powered at 120 volt or 240 volt, or powered by a small gasoline engine became available. These were all wet cut; designed to be run with water. In those days you were a considered a “real” mason contractor if you had 14” and 20” masonry saws on your jobsite.
For many, many years, wet cutting was the only way to cut. All of these saws required water to keep the blade cool. Water was required to avoid over heating the blade, melting the brazing or weld between the segment and the steel blade core, and potentially losing one of the diamond embedded segments. A secondary benefit of using water was that it helped control the dust.
Dry Cutting Blades
Options for dry cutting masonry in the 50’s, 60’s, and 70’s was limited. Mason contractors started to cut dry using carborundum type abrasive blades. Although the cost was much less than diamond blades, a major drawback was that the blades wore out and disintegrated fast. Within 10 to 15 minutes you could go through a 14” blade. Now you are dealing with not only the dust generated from dry cutting, but also the dust and debris generated from the carborundum blade as it disintegrated. In addition to the silica dust, asbestos was also found in some of the blades.
During this era, dry cutting was not typically a consistent option because of the excessive blade wear. This all changed in the early 1980’s when laser welding from the aerospace industry was used to laser weld a diamond segment onto the steel blade core. This opened up a whole new set of opportunities for mason contractors to use dry cut blades on their wet cut 14” and 20” wet cut saws, as well as other electric tools like angle grinders and 7” worm drive saws. With the availability of the new laser welded 12” and 14” dry cut masonry blades, contractors started to use handheld power cutters. The “Quickie Saw”, as it was nicknamed, became a very fast way to make cuts. You could use it right on the scaffold, but they were not as accurate as using a masonry table saw.
In the 80’s and 90’s, cost was a major drawback to the diamond blades. A 7” dry cut blade sold for over $100, and 14” and 20” blades could sell from $ 400 to over $800. But the advancements in dry diamond blade technology increased the use of masonry saws on all types of construction projects and became a multibillion-dollar industry.
Wet Cutting Innovations
Wet cutting was the standard in the masonry industry for several years and many innovations occurred during that time. Increased cut capacity helped expand what masons could do on jobsites. Lighter weight saws were developed resulting in better portability on the job. Water flow control innovations somewhat reduced slurry and runoff. Beveled cut innovations on masonry saws made it easier and more efficient to make specialty cuts.
Dry Cutting Becomes an Adopted Practice
Up until the year 2000, there were no real purpose-built, dry cut masonry saws. Contractors were just putting dry cut blades on wet saws, but without using water. That year, MK Diamond introduced the first lightweight, purpose-built, dry cut masonry saw developed by a mason contractor.
These lightweight masonry saws became adopted into the industry very quickly with several manufacturers started producing and competing in that market. The huge increase in the number of dry cut masonry saws and their blades being used created a major obstacle in the masonry industry; the amount of dust generated on masonry construction jobsites increased significantly. This increase in the dust did little to sway mason contractors from using these tools because they were used to working around all different types of dust on jobsites for many years. It has only been in recent years that the construction industry has come to realize the serious effects that daily long-term exposure to dust which contains freshly fractured silica can have on the lungs and health of construction workers.
Dry Cutting Options – PPE or Vacuum Systems
In the 70’s, 80’s, and even the 90’s, Personal Protective equipment or PPE, was not commonly used by construction workers, especially on smaller jobsites. Protecting your eyes, ears, and lungs was not a high priority and, in some cases, was looked down upon as though you weren’t a real man’s man type of construction worker. As a contractor, it can be very challenging to get employees to adopt best work practices and use proper Personal Protective Equipment (PPE). With an ever growing number of employees not employing these safe work practices has increased the number of construction workers overexposed to preventable health and safety risks.
As awareness of the issues and risks related to dust exposure have become better understood, industry leaders and associations have taken action to educate the trades and provide more options to create a safe work environment. Because of the industry demand, many new tools have been developed over the last 10 to 15 years by multiple manufacturers of masonry saws. These manufacturers have designed and built dry cut tools or accessories that use a separate vacuum attachment or vacuum system.
The construction industry is moving in the direction of dry cutting with vacuum systems as the preferred method of cutting – eliminating the use of water, eliminating slurry, staining, cleanup, and potential contamination of soil from the water runoff. Employing dry cutting with vacuum systems is changing the way mason contractors work on their jobsites. Every day, more and more contractors are moving toward this new practice.
OSHA and the new Silica Standard
We cannot talk about masonry, wet or dry cutting, without considering the new OSHA Silica Standard and the Permissible Exposure Limit or PEL. The new PEL is 50 micrograms of respirable silica dust per cubic meter of air. This new standard impacts everyone in construction, and specifically the masonry industry. OSHA approves both wet and dry cutting. Per the OSHA Standard, any method that is used to keep your employees under the PEL over an 8-hour, Time Weighted Average is compliant with the new standard. The OSHA Standard allows both contractors and/or manufacturers to do their own air monitoring tests to verify exposure levels.
These test results can be used on every job as part of a written exposure control plan that is used to train employees how to use a tool and how to keep their coworkers and themselves in a safe work environment. Other industry organizations are testing multiple types of wet cutting and dry cutting tools and their work-specified practices to verify employees are in a safe work environment and compliant with the new standard. That is the whole purpose and real intent of the new OSHA Silica Standard and PEL. We in the construction industry must strive to keep our employees, safe and healthy during all work activities.
Knowing what our options are for the right tools and the best work practices will help all of us in the industry. By using the right tools and working with manufacturers to develop improvements and accelerate new innovation, whether it’s wet cutting or dry cutting with vacuum systems. Understanding the harmful effects of silica exposure and complying with the new OSHA Silica Standard will keep our crews working longer, smarter, and more efficiently.
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