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      Diamond Grinder Information

      Looking into renting a diamond grinder for your project? Read our tips!

      DIAMOND GRINDER INFORMATION

      Since surface prep is a very important step in the epoxy-coating process, we often get asked about using mechanical methods of preparation, and our recommendations. Mechanical prep can be done by either using a diamond floor grinder or similar machines, or ‘shot blasting’. Please note that the below is informational only and you should always follow the manufacturer’s instructions on usage, care and protective equipment and we always recommend using a proper respirator to reduce the chance of breathing in silica dust. Eye and hand protection is also mandatory when doing any type of mechanical prep.  If, after reading the below you have questions or need further guidance, please reach out to us for guidance.

      1. SHOT BLASTING- Shot blasting machines are complicated and difficult-to-use equipment that should only be used by professionals. Armorpoxy does not recommend shot blasting for preparation for traditional epoxy coatings other than urethane cement. The reason for this is that shot blasting machines are very difficult to work with, and normally will leave ‘lawnmower lines’ in the floor that the coating will not hide. Even the slightest delay in moving the machine at a constant speed can lead to divots and marks being blasted into the floor, and the small overlapping area from going back/forth leads to those lines being ‘double blasted’ and hence leaving the line impressions in the floor. What shot blasters are good for are for removing dirt/grime/oils and such from rough/uneven floors since they prep from the ‘top down’ rather than grinding is which is ‘across’ the surface and only would prep the high spots of a rough floor. Shot blasting is an excellent type of prep for urethane cements, epoxy mortars and overlays which have aggregate in them, and are thicker, and will hide any patterns created by the machines. Contrary to popular belief shot blasting does not remove coatings or adhesives very well.
      2. DIAMABRUSH WHEELS- Diamabrush wheels are round wheels that have diamond pads on them that get used with a traditional floor buffer. These tools can be rented at Home Depot, and the wheels are sold also by Armorpoxy to fit on any buffer. The wheels use ‘blades’ that come in two grits, #25 (rougher) and #100 *(smoother). Diambrush machines work reasonably well for smaller projects and basements and will remove older/thinner coatings. Make sure that your wheel uses the #100 blades, as the #25 can and will leave deep scratch marks in the floor that a coating will not hide fully. Also if renting these tools, make sure the blades are not too worn out from previous rentals. When using a Diamabrush you must vacuum the floor very well after use to get rid of the extensive dust.
      3. DIAMOND FLOOR GRINDERS- These are machines that can be rented at some home centers or tool rental places like Sunbelt Rentals, United Rentals, etc. Also any local floor prep or local epoxy company should have these machines and you may be able to sub-out the prep portion only if your area is very large and you don’t want to tackle the prep yourself. Note that it is VERY difficult to ‘fix or level’ a floor by grinding it other than if you have a few bumps or high spots. Also a grinder does nothing to irregular floors with lots of damage and low spots since it moves ‘across the floor’ and only grinds the tops of the aggregate. Attempting to lower a floor height or fix a floor by grinding is almost impossible, and best left to professionals with very large and heavy equipment. Grinders have motors which spin discs called diamond pads or ‘tooling’. The tooling comes in many grits and hardnesses and is easily changed on the machine. The lower the grit number the more aggressive the grinding will be but also more aggressive grinding may result in swirl marks that can show through a coating so some jobs may require multiple passes with different tooling starting with more aggressive and finishing with less aggressive. Machines come in a wide variety of sizes, weights, voltage requirements, etc so select your machine accordingly and think about how you can move and handle the machine as larger machines can weigh hundreds of pounds since it is the downward weight that helps the grinding. For smaller projects a simple machine either 115v or 230V with a single or double head should suffice. Generally, #80 tooling up to #120 won’t leave swirl marks. Over #120 won’t do much preparation. If you need more aggressive grinding consider using lower grit tooling to get the floor in good shape, and then a second pass with higher number tooling to remove the swirl marks.
        NOTE-ALL GRINDERS MUST BE HOOKED UP TO A PROPER SELF-CLEANING VACUUM TO COLLECT THE LARGE AMOUNT OF DUST CREATED BY GRINDING SINCE A STANDARD SHOP VAC WILL PLUG UP AND LOSE SUCTION FROM CONCRETE DUST IN MINUTES. ALWAYS RENT A GRINDER WITH A MATCHING PROPER VACUUM. ALSO THE FLOOR SHOULD BE VACUUMED SEPARATELY AFTER GRINDING TO REMOVE EXCESS DUST.
      4. HAND GRINDING- Small floors can be hand grinding with 7” hand grinders with ‘diamond cup wheels’. These wheel can often leave swirl marks since they are normally not available in higher/less aggressive grit numbers and tend to be used more for fixing small spots, sidewalk edges, rough areas, etc. Using a hand grinder to prep is difficult and messy work and we suggest making sure your grinder has a dust shroud hooked up with a hose to proper vacuum. Make sure to wear full eye and hand protection and a full respirator to avoid inhaling silica dust.