Polishing & Grinding

Frequently Asked Questions

• What grit should I start with when sanding GFRC concrete?

  When using Domcrete Super Flex Pads, the appropriate starting grit depends on the condition of the GFRC surface after demoulding and the level of material removal required. The pads are available in 50, 100, 200 and 400 grit, allowing you to progressively refine the surface from initial preparation through to a smooth finish.

  • 50 grit – for aggressive material removal, flattening high spots, and correcting uneven surfaces
  • 100 grit – for general surface preparation and removing minor imperfections following initial grinding
  • 200 grit – for refining the surface and removing scratches left by the previous grit
  • 400 grit – for final refinement, leaving a smooth surface that’s ready for sealing or further finishing

  Always work through grits progressively. Skipping grits leaves deeper scratches that finer grits cannot fully remove.

• Can I use these concrete sanding pads with a grinder?

  Several products in this range are designed for use with a polisher, and in most cases a grinder, covering everything from aggressive material removal through to fine surface preparation:

  • 4″ Turbo Cup Wheel – suited for aggressive grinding and material removal in GFRC and concrete applications. Ideal for removing excess material from the underside of moulds and forms, and for aggressive grinding where heavy stone or aggregate needs to be exposed.
  • Super Flex Pads – designed for wet or dry sanding and refining GFRC and concrete surfaces. The flexible diamond pads follow contours and edges while progressively removing surface imperfections and refining the finish.
  • 5″ Standard Backer Pad and 5″ Aluminium Backer Pad – designed for use with polishers and other tools fitted with an M14 attachment, providing a secure mounting base for compatible sanding, grinding, and polishing pads.
  • Poly Blue Concrete Polishing Pads – compatible with high-speed polishing applications including buffing sealed surfaces to a smooth, soft-touch finish, while helping remove fine micro-scratches and surface imperfections.

  For hand-finishing on smaller pieces such as benchtops and decorative panels, the Hand Polishing Pads and Excalibur Hand Pads are used without a machine. Check each individual product page for compatibility details, or contact the team if you are unsure which pad suits your tool.

• Do I need a dust extractor when sanding or polishing concrete?

  Yes. Dust extraction is strongly recommended and in many contexts is a WHS requirement. Concrete dust, even from GFRC mixes that use silica-free premix formulas, can still contain fine respirable particulate during the sanding and grinding stages. Domcrete stocks a complete Mirka extraction system to suit professional studio and workshop use:

  • Mirka Dust Extractor 1230 M AFC – designed specifically for use with the Mirka Deros II, providing effective on-tool extraction during sanding
  • Mirka Vacuum Hose – connects the sander directly to the extractor for a clean, continuous workflow
  • Mirka Sleeve + Cable + Hose – a complete connection kit for the full Mirka sanding and extraction setup
  • Mirka Clean Up Kit — for general workshop dust management between and after sessions

  For any dry grinding operations, always use extraction alongside appropriate respiratory PPE. If you are working with silica-free GFRC premix, your base material is already formulated to reduce silica exposure, but surface finishing still generates dust that must be managed.