One of the fundamental rules which applies to us when grinding a surface is to gradually expand the working area. If we have levelled out the area with the ripping discs, then when we move to the “00” type discs, we have to move the sander a few centimetres beyond the levelled area. The point is to remove the scratches on the edges of the sanded area. The same applies to all subsequent gradations of the discs. Having finished work with the disc which we have marked with the number “00” (or the manufacturer has done it for us), we put on another one, in our case “0”, and expand the sanding area again. In this way, we have to go through all the gradations of a given set. The exception may be the highest grades (“800”, “1200”, “1500”…), when the scratches are already so small that it does not matter much, because they are not visible. As you can see from the above, you should not use the first grade of the tool to reach the very wall or pillar, because we will not have the possibility to widen the sanded surface during the next phase of work.
After each stage of sanding the surface, the sludge must be removed with a suitable industrial hoover. This of course applies to wet sanding using water. If the sanding process is carried out dry, the sanding dust is extracted using a hoover on an ongoing basis.
It is also a good idea to clean the surface to be sanded after each subsequent stage. This is particularly important at the final stage of work, where a single grain of sand brought in on our shoes or blown by wind into the room can scratch the surface if it gets into the working area of the sander.
When working with water we must also take into account the absorbency of the stone. It may turn out that working with water will not be possible at all or it may require additional measures connected with thorough sealing of joints or drying.
Places which cannot be reached even by the smallest machine have to be manually polished with an angle grinder. The principle is similar to that of working with larger machines but requires much more skill and intuition. Damaged stone is quite common, unfortunately. Instead of beautiful art, we get the mundane quality of life, then.
Such free creativity can also be seen where the worker decided that it was taking too long to level out the surface and decided to use an angle grinder on all major irregularities. This way, although he worked harder, he saved a lot of time and money. The result, now how satisfactory it looks at first sight, deserving a layman’s applause, presents nothing but a poor tragicomedy a short while after.
Sanding the stone surface does not mean the end of the job. If we want to achieve the best possible result, when it comes to marble flooring, we still need to take the time to carry out the crystallisation process. What it is and how many misunderstandings there are about it, we will discuss in the next issue of the magazine Kurier Kamieniarski.
Source: Kurier kamieniarski
Author: Artur Janus | Published: 12.05.2021