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Third Step: Polishing

If the stone floor is already ground and you use the correct "make" of honing/polishing diamond pads, that alone will be sufficient to finish the polishing job. Although it is a sound and fool-proof method to polish stone floors with resin-bond diamond pads, it is quite time-consuming.

In this article, we will analyze the polishing job with powder. After all, it is the one that will polish the largest range of marbles. But, above all, it's the only possible component that can work on a non-ground floor over a two-step restoration procedure, a restoration job most frequently performed by all stone restoration contractors.

Wet Polishing: Step by Step

The most popular way to polish a marble floor is wet polishing. But unfortunately, you have to use a relatively large amount of water - though certainly not as large as the quantity of water necessary to grind and hone.

1. Target a section of the floor no more than 15 to 18 square feet. Always keep in mind that we're referring to an average stone. Certain marbles will allow for larger sections, and others will demand smaller ones.

2. Start by pre-damping the target area by releasing a little bit of water from your water tank. Then, spread it swiftly with your swing machine set-up with a natural fiber (hog-air) polishing pad or any other suitable polishing pad.

3. Apply the "required amount" of polishing powder on the middle of the targeted, pre-dampened section. Please ensure to distribute it evenly over an area to be entirely covered by the polishing pad measuring about 13 inches.

What is the Correct Amount of Polishing Powder?

If you wonder what the "required amount" is, there is no way to define it as there are too many variables like:

• Make of the powder
• How "hot" the powder is
• Type of machine
• Type of marble at hand

Only years of experience will make the proficient contractor understand the "required amount" of polishing powder one will need. It may be as little as a teaspoon or up to as much as half a cup. Even trying to indicate an average would represent useless guesswork.

4. Position your swing machine on top of the polishing powder, release a little bit of water, and swiftly spread the thick slurry over your targeted section of the floor.

5. After a thorough spreading is done, you may begin the actual polishing, starting from one end of the targeted area and moving as quickly as the situation will allow toward the other end. Work on a spiral or coil-like pattern, ensuring to go approximately half a foot or so over the top and the bottom of your targeted section of the floor. It will ensure a perfect blend of the sections. 

For Example, suppose your targeted area is represented by three rows of 12"x 12" tiles by five or six columns, making a total of 15-18 square feet. In that case, you will polish approximately half a foot into the row above and again approximately half a foot below your targeted area by increasing the swing of your up and down movement accordingly.

6. Go over it approximately half feet at both ends. Once you reach the end of your targeted area, release more water and re-do your coil-like pattern work going in the opposite direction.

7. Once you reach the end again, release more water and swiftly re-do your working pattern by going again in the opposite direction. At the same time, your helper will begin sucking up the slurry with a wet-and-dry vacuum cleaner, possibly positioned in front of you at the opposite side of your targeted section.

8. At this point, the targeted area should already be polished and, if it turns out that it isn't, it means that you will need to rethink the following factors:

• The amount of powder used to do that section
• The make of polishing powder
• The size of the section itself
• The pace of your work

9. You will have to rethink those factors even if you over-polished your first section and "burned" the stone surface. In this case, of course, the rethinking will have to go in the opposite direction, which means: 

• Consider using less polishing powder
• Maybe using more water since the beginning
• Using a "colder" polishing powder
• Increasing the size of the section
• Maybe speed up the pace of your work

Is the Floor Properly Polished or Not?

How do you determine if the marble is properly polished, under-polished, or over-polished? The latter pass with lots of water as described above is not meant to polish anymore; it is rather meant to loosen the almost dead slurry and suspend it in water in a way that the sucking action of the vacuum will remove all the slurry and leave the surface of the stone clean except a few streaks and ready for inspection.

The Interplay of Calcite and Acid 

The importance of determining the size of the single sections of the floor to be polished depends on the calcite in the stone. The acid part of the polishing compound will fight and eventually "kill" each other. Therefore, the polishing must be done during the window of time the polishing compound - activated by the water - will stay "alive." After that, the compound won't work any longer, and stopping before its "death" could produce time-consuming, hard-to-remove swirls etched on the floor surface.

It is important to start with a little water and increase its quantity as the work progresses. If you use a small amount of water initially, part of the compound will be stuck under the pad, inactivated; hence it will not die and will be ready to be called into action with the next release of water.

If honing pads achieve better clarity, the size of the targeted area could increase exponentially. It also proves the economic importance of the clarity obtainable with the "right" honing pads. No doubt, in many cases, the superior final visual result will be a bonus.

Factors Determining the Size of Targeted Area:

1. The percentage and purity of the calcite in the marble at hand
2. The kind of clarity that you obtain with the honing pads
3. The type and speed of the machine
4. The make of the powder
5. The type and make of polishing pad