If you ask a diamond wheel sellers about their grinding wheels, there's a good chance they will give you the classic "grinds fast, long life" to describe their products.
Diamond grinding is a mature technology, and there are effective ways a manufacturer can alter the performance of their grinding wheels. Diamond grit size and bonding choices are the primary factors that determine a wheel's performance.
- Diamond grits are the grinding agents. Naturally the bigger and higher-grade they are, the more aggressively the wheel will grind.
- The common grit size for concrete wheel is #30/40.
- More aggressive grinding wheels will sometimes use #20/25 diamond grits.
- Bonding is the material that holds the diamond grits together. An optimized bonding formula should accomplish two things:
- Holds the diamond grits firmly to increase grinding life time.
- When the grits do grind away, it should expose the next layer of grits quickly.
We did some testing to see the effects in action, and here's what we've found:
Grit Size
- A #20/25 wheel grinds about 30-40% faster compare to a #30/40 wheel. (on concrete, with same type of bonding)
- However, the lifetime is reduced by about 10%-15%
Bonding
- For concrete under 4000 psi, the difference between a low cost bonding and a high end bonding isn't significant.
- For concrete over 4000 psi however, using an optimized bonding grinds 20-40% faster, and increases lifetime by 50-80%. They also feel a lot smoother during use.
With consideration to labor costs, the performance and lifetime you get with better grit and bonding will be well worth its higher cost.
If we are also grinding epoxy, mastics, glues, etc., the higher grit size and bonding become a necessity as the lower end grinding wheels will struggle to function on such tacky surfaces.