Page 15 - Demo

Slippery Rock Gazette
November 2024 | 15
Stone Restoration and
Stone Restoration and
Maintenance Corner
Maintenance Corner
Diamond Abrasives
IFyou’re old enough, you may remem- ber when commercial buildings in the 60s, 70s, and even 80s were constructed mostly of concrete, steel, and glass. This new look was trendy at the time, but no- where near the timeless beauty of natural stone. Unfortunately, natural stone had become too costly to fabricate, especially with the existing tooling and methods of
that time.
Folks, I’ve been in the business for well over 45 years now, off and on. I helped make silicon carbide bricks (Frankfurt and other style abrasives) for radial arm and automatic line machines when I was 12 years old (in 1970, for Greenstone Products). I used to hang out on Saturdays at Candoro Marble Company, here in Knoxville, because my Grandpa worked there. There were no industrial diamonds on the scene at that time, at least in general production, anyway. Even the gang saws (saws that cut blocks into slabs) were sil- icon carbide and or used sand as the cut- ting abrasive.
I then started working for my dad, Vic Green, at VicCo (later called Vic International) selling the Frankfurt bricks and other fabrication tools and equipment. I remember the first industrial diamond tools to hit the market, like core bits, blades, and such. Later, there were Frankfurt style dia- monds. All of these diamonds were met- al-bond (sintered) segment types. Soon, there were electroplated metal diamonds available and ultimately the resin-bond dia- monds made their appearance.
Why use diamond abrasives? To start with, diamond is the hardest material you can use to polish, grind, or cut stone, being a 10 on the Mohs Hardness scale. Diamonds cut much faster than silicon car- bide or other abrasive materials. They also hold their shape and sharpness much lon- ger than softer materials. Because of these features, there is less abrasive material in the cutting wastewater (slurry). This is not as much of a problem in the fabrication and production facilities where they have plenty of water and are able to recycle (fil- ter) the wastewater.
As restoration contractors, however, water usage must be managed to a much
Bob Murrell
M3 Technologies
Photos by Bob Murrell
Segmented metal bond MAGNUM MAG3- 0400 grit mounted on a GRIP magnetic plate, closeup, below.
AA Turbo Polishing PADS, epoxy resin discs
finer detail. Our operations are in commer- cial and residential structures, not in a plant with water recycling. We need the cutting speed and the longevity of diamond abra- sives, and don’t need the massive amounts of water needed to run silicon carbide abra- sives. So, diamond abrasives are the best tool for most stone, terrazzo, and concrete grinding, honing, and polishing operations.
Let’s discuss some of the most pop- ular diamond abrasives for stone, ter- razzo, and concrete restoration industries. Remember, our cutting operations are usu- ally done wet, except for certain concrete applications. We do heavy grinding opera- tions, like lippage removal, as an example. Standard honing operations, say for coun- tertops and floor traffic wear lanes, are typ- ically started with a 220 grit followed by a 400 grit and in some situations an 800 grit, prior to polishing with a 5X Gold or simi- lar polishing abrasive.
Typically, coarse grinding operations are completed using a metal-bond diamond of
some type, as these are the most aggres- sive. Honing operations are usually com- pleted using resin-bond diamonds of some type, as these will provide a smoother fin- ish. Epoxy resin diamonds tend to give a higher finish per grit level than do the phe- nolic resins, but the phenolics cut faster. I like the epoxy resins for most marble and similar stone countertop operations.
At M3 Technologies Inc. we have many diamond abrasives to choose from, based on the application. Our most popular epoxy resin-based diamonds are the Triple Thick TX 3-inch series for floors and the AA Turbo 5-inch for hand tool work. The AA Turbos come in several sizes, up to 7 inch. Made in Bulgaria, the TX resins are the standard in the industry for floor work. Both the TX and AA series cut fast and leave an excellent finish after each grit level. The TXs are somewhat flexible, which can help accommodate mild lippage on floors.
Please turn to page 17
Rosette epoxy resin discs