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What disc should I use to grind hard concrete

As the dust from hard concrete is soft and un-abrasive the metal MATRIX that the segment is made of needs to be ‘soft bond’ and easily eroded to expose the diamonds. Often having a coarser grit can be beneficial too because it may produce coarser dust to help erode the matrix.

In addition, reducing the contact area with fewer segments makes a difference. This also has the effect of increasing the weight per square inch on the surface so that the diamond grit will occasionally crack a little bit off the peak to create a fresh sharp peak and start grinding again.

Diamond grit will gradually round over if it does not crack off a little bit from time to time. Rounded grit won’t grind too well. This is why you will find that adding extra weight or ensuring all the weight of the machine possible is on the head; helps to keep the diamonds working.

The 5 steps to grinding hard concrete …

  1. Use diamond tooling with a SOFT BOND and/or less segments and increase the weight on the diamond tooling. Using coarser grit diamond may increase the dust size and keep the tooling working.
  2. Do not use tooling for hard concrete on soft concrete; they will almost certainly wear out incredibly fast.
  3. Turn down the vacuum so there is plenty of dust under the machine; this will help the diamonds to expose. Careful addition of sand may also help. Don’t overdo sand, it could cause premature wear!
  4. Watch out for the situation where there is a hard-to-grind top layer, and a soft layer below. You can wear out discs fast and you think that’s because the top is hard, the discs should last. If this occurs, use the soft bond only to, or nearly to the soft layer, then grind the soft layer completely separately with hard bond discs.
  5. Lastly inspect your tooling. If there is hardly any diamond exposed out of the matrix, and/or the tooling is getting hot, stop and change to a softer bond, or less segments.

Top Tips for Grinding Hard Concrete …

When the concrete is ‘hard’ often wetting it before grinding helps to expose the diamonds a little more. This helps makes the dust a little heavier which cuts the matrix more to expose more diamonds. To do this try to …

  • Scratch open the surface first
  • Then apply water and give it a little time to soak in
  • Broom off the puddles and remaining water leaving the surface wet

It will seem that the water has done nothing when you grind because the dust is the same as if you never wet the floor, but grinding will be more productive.

Repeat this process for each new cut If all else fails, you can also try spreading a small amount of sand on the ground and lightly wetting it to help further break down the bond of the diamonds.

If you are unsure which diamond tools to use, contact Con-Treat today. We can advise you on the best option for your needs.

* The above information is to be used as a guide only and Con-Treat accepts no responsibility for any consequence resulting from the advice contained herein or verbally.

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