Concrete polishing tools mainly include the following:
PCD coating removal discs, which are used to remove coatings on concrete floor, they are needed when there is thick coating like epoxy on the floor.
Diamond grinding discs, usually use for concrete floor leveling and old floor renovation.
Thick diamond polishing pads, usually refers to resin bond polishing pads with thickness of 5mm or more, which are used for concrete floor leveling, grinding and polishing.
Thin diamond polishing pad, usually refers to resin bond polishing pads with thickness less than 5mm, which are used for fine polishing.
Sponge polishing pads, usually use man-made fiber, wool or other animal hair as base/support and with diamonds and abrasives sprayed and immerged inside the base material.
There are so many kinds of polishing tools for concrete floor polishing, how to select and use them?
In order to choose and use polishing tools correctly, we must first understand the following nouns:
Flatness of the floor
For floors which was trowelled or leveled manually or old floors which are loose and seriously damaged, it is necessary to level or remove the loose surface layer. We need to use high power grinder and aggressive diamond grinding discs to level the floor before polishing. For self-leveling floors or floors that leveled by power trowel machines, we can get beautiful polished floors with resin bond polishing pads only.
Hardness of the floor
Cement which is used to pour concrete floor is represented by a number, like C20, C25, C30 etc. that we usually talk about. Under normal circumstances, the higher the number the harder the concrete, but due to various factors, the number of cement and hardness of the floor are often not corresponding. Hardness of concrete floor is usually expressed by Mohs hardness. Mohs hardness of concrete floor is usually between 3 and 5. On the construction job site, we can use some substitutes instead of the Mohs hardness tester to know hardness of the floor. If we can get dents or scratches on the floor with iron nails or keys then we can say the concrete hardness is less than 5, otherwise, the hardness is more than 5.
Quality and speed of the grinder
Floor grinding machines are usually divided into light weight, medium size and heavy duty grinders. Heavy duty grinders have higher power so higher efficiency. In actual applications, when it comes to grinders, it is not the larger the better. Although the grinding efficiency of heavy duty grinders is higher, it also very likely to lead to excessive grinding so increase the construction cost. Experienced contractors will adjust rotating speed, walking speed, number of grinding discs and counterweight of the machine to reduce construction cost and improve construction efficiency.
Type and size of polishing tools
Widely used tools for concrete floor polishing are PCD grinding discs, metal bond grinding discs and resin bond polishing pads. PCD grinding discs are used to remove thick coatings on the floor surface, metal bond grinding discs are used for floor surface preparation and rough grinding, resin bond polishing pads are used for fine grinding and polishing. Grit number of the polishing tools refers to size of diamond particles contained in the tools. The lower the grit number, the bigger the diamond particle size. There is no grit number for PCD grinding discs, but they have direction, clockwise and counterclockwise. We need to pay attention to its direction when use a PCD. Metal bond grinding discs are usually come with grits 30#, 50#, 100#, 200#, 400#. Usually we determine which grit to start according to the floor conditions. For example, if the floor level is not good or the surface is relatively loose, we may need to start with 30# metal bond grinding discs to remove the loose surface and level the floor. If we want to expose aggregates, 50# or 100# metal bond grinding discs are necessary. Resin bond polishing pads come with grits from 50# to 3000#, different grits are distinguished by different Velcro color. There are thick polishing pads and thin polishing pads. Thick polishing pads are rigid suitable for medium size and heavy duty grinders. Thin polishing pads are flexible suitable for light weight grinders for fine polishing.
When you understand the above 4 factors that affect our choice of polishing pads. I believe you already know how to choose the right polishing tools for your concrete floor polishing application.