There are four basic methods used today to create a shine on natural stone floors: Buffing with polishing powders and compounds, grinding with diamond abrasives, crystallization and applying barrier coatings. Each method may not be effective on all stone types and the use of more than one may be necessary.
Polishing Powders and Compounds are fine grains of aluminum or tin oxide abrasive powder that are buffed or rubbed on the surface of the stone to create the shine. This process is actually the same as sanding with diamonds except that the powder is a much finer abrasive. This process is most often augmented by the addition of oxalic acid or oxalate to create a reaction similar to crystallization. The powder is put on the surface and wet with water to make a paste or slurry that is buffed into the stone with a 175 rpm weighted floor machine and a hogs hair or white pad.
Grinding with diamond abrasives is done by grinding the surface of the stone with various grits of industrial grade diamonds that are usually in three to four inch diameter pads or discs. Three to six discs are placed on the bottom of a floor machine drive plate and held on with Velcro. A low speed (175 rpm) floor machine is used to drive the plate and sand the stone surface with the diamonds to remove scratches. The process is repeated with finer and finer grits of diamonds until a mechanical shine is achieved.
Coatings are commonly known as “waxing” the surface to create an artificial shine. A liquid or semi-liquid form of wax, acrylic, urethane or other polymer is applied or “coated” on to the surface with a mop, roller, lambs wool applicator or sprayer. Some are left as applied and others must be “buffed out” to achieve the shine. This is generally done with a high speed burnishing floor machine and fiber or hogs hair pads. This process is not recommended for porous stone.
Crystallization is a process in which a chemical called fluorosilicate is sprayed onto the stone and buffed in with steel wool pads causing new, glassy like, crystals to be formed on the surface. A standard 175 rpm floor machine with a special heavy drive plate is used to create the heat and friction needed to form and polish the crystals.
What are the Advantages and Disadvantages of Each of the Polishing Methods?
The following pros and cons are presented from the view point that polished marble, granite and limestone are chosen for use on floors because of their “natural” appearance and beauty. When cost is shown as an advantage or disadvantage, it is only to compare one method with the others. Most often the owner’s expect the cost of maintaining natural stone floors to be higher than that of other resilient floors.
Polishing Powders and Compounds
ADVANTAGES:
1. Gives a natural appearance with a high gloss and sheen.
2. Produces a relatively durable finish.
3. Never requires stripping.
4. Can be applied with a standard low speed weighted floor machine.
5. If oxalic acid or oxalate is included in the powder, it will remove fine to medium scratches.
6. Only done periodically, not daily or weekly.
7. Compounds composed of aluminum oxide will not etch floor.
DISADVANTAGES:
1. A messy process, requiring additional work to clean up.
2. If oxalic acid is included in the powder, it can cause etching or blistering of marble and limestone depending on the skill of the person using it.
3. Requires equipment (i.e., a floor machine, wet vac, mop, mop bucket, etc.).
Grinding with Diamonds
ADVANTAGES:
1. Is the most natural method.
2. Very durable, long lasting finish.
3. Never requires stripping.
4. Will remove all scratches.
5. Works well on marble and granite.
DISADVANTAGES:
1. Requires an initial restoration of the floor to remove or bevel the lippage that can/will damage the fine grit diamonds used.
2. Highest cost method in both material and labor.
3. The final polish and clarity vary depending on the stone and generally have to be augmented by using powder, polish or compound.
Coatings
ADVANTAGES:
1. Most janitorial maintenance personnel are familiar with this method.
2. Can be lowest cost method if not concerned about the appearance.
3. Generally provides good slip resistance.
DISADVANTAGES:
1. Does not provide a natural appearance.
2. Most coatings do not adhere well to polished stone.
3. Scuffs and dulls very rapidly.
4. Requires daily buffing or burnishing.
5. Requires periodic stripping that is messy and damages the stone.
6. Blocks the pores of the stone which, coupled with stripping, can cause spalling.
7. Can be a high cost method if done properly to maintain the best possible shine.
Crystallization
ADVANTAGES:
1. Gives a natural appearance with a high gloss and sheen.
2. Very durable, long lasting finish.
3. Easy to use and does not require any special skills.
4. Very clean, no mess.
5. Will remove fine scratches and polish heavy scratches.
6. Do not have to polish the entire floor. Can “touch-up” high traffic areas.
7. Can be applied with a standard low speed floor machine.
DISADVANTAGES:
1. Can discolor or darken some light colored grout.
2. Can cause a slight yellowing in some stones if moisture is present. (The yellowing can be removed with the appropriate chemical)
3. Possibly slippery if over buffed.
4. Has limited affect on most granites.
5. Requires periodic stripping.
6. Scuffs caused by wax.
7. Steel wool sheds and rusts.
8. Steel Wool will last up to 500 sq ft.
9. Over use produces a non-responsive floor.
10. Quick fix surface shine only.
