Sealing

Water Repellents

• Silicone (synthetic oils) - Generic synthetic oils which tend to leach from surfaces and migrate. They are of limited use.
  
• Siliconates - Water based silicone-derivative useful for light colored, porous stone. They are inexpensive.
  
• Siloxane - These are state of the art today in long-life and high vapor transmission. They are moderately priced.
  
• Stearates (metal soaps) - This is the cheap water repellent sold to consumers in chain stores and hardware stores for wood, concrete, masonry, etc. Performance is poor and short lived. They are not recommended.
  

Oil Repellents

These are proprietary products which repel oil as well as water and other liquids. There are a number of these specialized products designed for use on stone surfaces.

Drying Oils

These are the original natural polymers. They include tung, linseed and soy. These oils become solid as they dry and are of potential use for sealing stone surfaces. They are organic and, hence, they are relatively sensitive to aging and may yellow with age but are useful in some situations. Check for proper use with your local stone dealer.

Waxes

Waxes may be natural or synthetic and include carnauba, paraffin, montan, beeswax, etc. They are typically formulated into paste waxes or emulsions for sealing purposes. Their effect is less than permanent, and typically they must be reapplied on a regular basis.

Silicates

These are mineral glasses which fill up pores and densify porous surfaces. They are very useful for restoration of stone which is under chemical attack or exterior weathering as it can replace lost minerals (repair) and provide protection from further degeneration. They are specialized materials which require expertise to formulate and apply for predictable results. The use of silicates is not recommended for the "do-it-yourselfer".

Finishing/Dressing

Waxes (Professional)

This category is primarily professional paste waxes composed of paraffin, beeswax and some synthetics. They can be very effective for maintaining a shine and prevention of stains. Some professional products contain dyes or pigments which can be useful in bringing out or maintaining the colors of red, black, and green stones (primarily for furniture). Carnauba-based waxes may be suitable for some low-abrasive surfaces and is used in specialty maintenance products. Using wax on natural stone may result in build-up staining due to grinding the soiling agents into the layers of built-up wax. Further damage may occur from acidic residues in the soiling agents or from the chemical composites of the wax itself. Propellants from spray wax of any sort will act as an etching agent on any polished stone resulting in a dull appearance.

Further surface blemishes and streaking may result by the use of non approved wax for applications to stone.

Wax of any kind should not be applied to honed stone. Natural variations of color and brilliance will be apparent. This is a natural occurrence due to varying density of composites or deposits of all stone. This is especially inherent to honed stone, a natural finish.

Professional waxes used during fabrication are mentioned to fully educate the consumer. These waxes are used by the professional fabricator to assist with natural cosmetic requirements. Natural pitting, veining and seam blending, require a bonding agent to blend color variations. Professional waxes used in this case are used during fabrication of the stone or at installation. Use during installation should be prior to a final cleaning and seal coat. Waxes should be hardened and all excess residue removed.

Coatings

Coatings are usually acrylics, urethanes, epoxies, varnishes, lacquers, etc., and have limited use on natural stone. However, there are some typical uses of these film forming polymers. The most common coating is the janitorial-type floor finish that is applied to floors to maintain a physical barrier that isolates the stone surface from abrasion. These coatings are considered temporary or sacrificial and are used primarily because the coating is easier to restore when it gets damaged than the stone sure would be without the coating.

Soaps

Soap is potentially useful in a number of categories because of the residue that soaps tend to leave behind. The residue can be utilized as a sealer in some situations or may be intentionally built up and used as a natural paste wax or dressing. Soaps are very valuable for maintaining stone surfaces and in most cases are 100% reversible. Soap residues "dress" or nourish a stone, preventing the stone from drying out and being overly absorbent. Soaps add to the natural weathering beauty, or antique look.

Restoration

Consolidation

(Natural stone age and weather with time.) Binding of loose particulate is a desirable process when it is necessary to arrest degenerative processes. Limestone and sandstone are excellent candidates for binding processes which replace lost minerals that hold the stone together. There are many types of potential binding agents including various polymers (acrylic, urethane, silicones, polyesters, etc.) as well as mineral based silicates available. Caution must be exercised in the evaluation of a potential binding agent as the physical compatibility of the binder with the stone is critical. Binding agents and processes are underutilized today primarily due to the lack of knowledgeable restoration specialists. To the laymen, however, the simplest binding method for honed stone is cleaning. The very scrubbing process removes soil and grinds minute layers of stone back into the pours of the stone. The softer the stone, the easier the process. This process keeps the very outer layer of the stone pliable. Continued proper maintenance affords the stone the ability for on-going restoration, naturally.

Filling

It is sometimes desirable to fill cavities in natural stone in order to decrease maintenance costs, avoid mechanical trapping of soils and contaminates or for design considerations. During fabrication, stress by intrusion of the stone from cutting, releasing a vein, increases with every step. Staring with the removal of the stone block from its source (mountain or open pit quarry). Each time the rock is touched, it is prone to reaction by touch (handling). Veining may separate, fishers (a separation in the vein) may appear. To the touch, a fisher looks and feels like a crack in the stone. It is. It must be filled, using grout, stone dust, penetrating epoxy and resin.

Hardening

Some stones may be chemically hardened in order to resist abrasion more effectively. Limestone may be hardened by a number of chemical processes including silica impregnators and silico-fluoride treatment. Or, binding processes may give a hardening effect.

Strengthening

Stone strength is usually the result of an increase in stone density brought about by binding processes.

Grinding

Grinding is the historical method of restoring a worn and weathered stone surface to its original cosmetic condition. It is also the pre-conditioning stage for polished with oxides. Silicon carbide and diamonds are the most common abrasives used.

Polishing

This is usually a mechanical abrasion process sometimes coupled with chemical action. A typical polishing compound is composed of aluminum and/or tin oxides and water. Oxalic acid is used as an additive for polishing some marbles.


Stain Removal

Iron - Phosporic acid, sodium citrate and glycerin.
Copper & Bronze - Ammonium chloride and talc.
Ink - Sodium perborate, ammonia, various solvents.
Tobacco - Sodium perborate, soap, sodium carbonate.
Urine - Sodium perborate, sodium carbonate.
Fire - Tri-sodium phosphate and chlorinated lime.
Lubricating Oil - Acetone, aml acetate, TCE, aromatic solvents.
Linseed Oil - Hydrogen peroxide, ammonia, tri-sodium phosphate, sodium perborate.
Wood - Glycerin, tri-sodium phosphate, enzymes.
Coffee - Glycerin, ammonia, enzymes.