This is a question that we are frequently asked and it is a good question. If you are like me you like to know how things work so here we go.
There is a lot of confusion out there on how concrete polishing achieves a gloss. Many times we are asked "So when do you put the sealer/epoxy on to make it shiny?" Although we do use a sealer at the end of our process to protect the floor. (after all our weather is very harsh on floors) That is not where the shine comes from.
The beginning of our process is to grind the floor with a concrete grinder/polisher that has metal bond tooling on it. What is metal bond tooling? They are small tools that attach to the grinder, they consist of metal and industrial diamonds. These tools open up the floor to different degrees depending on what kind of aggregate exposure is desired by the client. For example we can start at a 16 grit for full exposure or we can start at 50 grit for little to no exposure. This can be done dry producing dust captured by a hepa vacuum, or wet producing a slurry that is a cleaned up with an auto scrubber depending on which system we are using.
Once the floor has reached a certain grit we then grout the floor. This is a process that fills in the porous areas of the floor to provide a more durable floor and a better shine.
At 100 grit or 200 grit we then apply a chemical densifier to the floor. To put it simply this product closes the pores of the concrete and strengthens the top layer of the slab. Also because the slab is more dense it provides a better shine in the end.
At this point we are using resin tooling. It is the same idea as the metal tooling being that it consists of industrial diamonds suspended in the tools.
We continue on up to a grit of 400, 800, 1500 or 3000 depending on what sort of gloss level the client desires.
At this point whether it be a light gloss or a mirror finish the shine is coming from the concrete itself. It is not a coating of any sort. It cannot yellow or peel off. We often liken it to a stone tile such as granite or marble.
At this point we recommend applying a sealer. Whether penetrating or topical, this will protect the floor from staining due to spills, It will also protect the floor against salt that comes in the door during our long maritime winters.
The floor is then burnished with a high speed propane burnisher to enhance the shine and remove any excess sealer.
Overall the process ranges between 5 and 13 steps depending on the slab condition and desired finish.
If you still have questions on the process please feel free to post them in the comment section!