Average response time: under 24 hours
Prevent aggregate tear-out by using a soft bond that releases diamonds quickly, taking light passes instead of deep ones, and keeping pressure low so the segments skim the surface instead of plowing it. Aggressive coarse grinding with a hard bond on a heavy-aggregate slab pulls the stones out of the paste and leaves pockmarks.
Large aggregate sits in a matrix of paste. When a coarse segment digs in deeply, it hits the stones at an angle and lever action pops them out of the paste before the paste is ground away. Hard bonds that keep the diamonds proud make this worse because they bite harder. The fix is to grind the paste down gradually so the stones are exposed smoothly, not yanked out.
Use a soft metal bond for the initial grinding on heavy-aggregate concrete. A soft bond wears faster and keeps the cutting action shallow and even, skimming the surface instead of grabbing. Hard bonds are for soft, low-aggregate concrete. If your diamond grinding tooling has multiple bond options, pick the softest that still cuts the paste at a reasonable rate.
Set the machine to take off 0.5-1mm per pass rather than 2-3mm. Keep the machine flat and move at a steady pace; do not lean on it. If you see stones pinging out or hear a clicking sound as segments hit aggregate edges, lighten the pressure immediately. Re-check the surface after each pass and adjust feed so the paste grinds ahead of the stones.
Once the paste is level with the stones, step through the normal grit sequence: 40, 80, 120 metal, then resin through 3000. Exposed aggregate polishes beautifully if the stones were never damaged. If a few stones did come out, patch the pockmarks with a matching mortar before polishing, then grind the patch flush.
A> On heavy-aggregate slabs, yes if run aggressively. Use 25-40 grit with a soft bond and light passes for the first grinding.
A> Wet grinding cools the bond and cuts more gently, which helps on exposed-aggregate work. It also makes it easier to see when stones are being damaged.
A> Patch the pockmarks with a color-matched repair mortar, let it cure, and grind the patches flush before continuing the sequence.
Heavy aggregate rewards patience: a soft bond, shallow passes, and light pressure skim the paste and expose the stones cleanly. Grind gently at the start and heavy-aggregate concrete becomes one of the most beautiful polished finishes you can produce.
Written and reviewed by JOY TECH - an SGS & BV audited, CE/RoHS certified diamond tools manufacturer founded in 2004, exporting to 50+ countries.
Our factory and quality management system are audited by SGS and Bureau Veritas. Products meet CE/RoHS requirements and every piece is 100% inspected before packing.
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