Frequently Asked Questions on Stone Care |
 Q: I dropped a bottle of vinegear and oil dressing on the polished travertine floor in my kitchen. Though I immediately cleaned it up, a dull area remains and I can't get the shine back on the floor. How can this be fixed?
A: The acid in the vinegear has reacted with the calcite of your travertine to create an acid etch mark on the floor. Acid etch marks are chemical changes in the stone, and no cleaner will be abel to remove them. The solution is to call The Stone Poets and have them either chemically polish out or first mechanically sand and then chemically polish out the area etched by the acid.
Q: I installed a marble floor in most of my downstairs nearly two years ago, and the front entranceway and hallway doesn't reflect light as well as it did when it was new. How can I return it to look like it did when it was new? Is there something I can coat it with so it will keep its polished finish longer?
A: It's typical for highly polished marble floors to dull down over time, especially in high traffic areas of the home (like entrances and hallways). Marble floors can be either chemically polished or first mechanically sanded and then polished to maintain their highly reflective surfaces. Coating a highly polished stone floor is usually not recommended. First, the stone needs to respirate (release water vapor) to remain healthy; coating a stone floor may inhibit this requirement, trapping moisture in the stone and causing big, long-term problems. Second, some coatings may increase the slip coefficient of some polished floors, making them slippery and dangerous. The beauty of stone is that it can almost always be restored to look like new. Call The Stone Poets for a free estimate on marble floor polishing and restoration.
Q: My mother-in-law told me to use a commercial ammonia cleaner on my granite countertops to keep them clean and shiny. Is she right, and can I use this cleaner without harming my beautiful granite counters?
A: Ammonia is a strong alkaline, and may have a harmful effect on your granite over the long term. It's best to use a pH neutral stone soap on your granite (and any other natural stone, for that matter) for regular cleaning. A good rule of thumb is never use anything to clean your granite that you wouldn't use to clean your hands (don't try and reverse that axiom!).
Q: Everyone keeps telling me to use a "neutral pH cleaner" for my natural stone. What exactly is a "pH neutral" cleaner and why is that important?
A: That's a good question. Many people in the business who are taught to recommend pH neutral cleaners don't even know. Here's a short primer on pH and its importance in cleaning natural stone floors and dimensional stone:
pH is the unit of measure used to express the degree of acidity of a substance.
The centimeter is a unit measure of length. The gram is a unit measure of weight. So, pH is the unit measure we use to say how much acid is in a substance. The pH scale goes from 0 to 14. A pH of 0 identifies a very high acid activity level. Substances such as lemon juice and vinegar are acidic with pH values of 2 to 3. Nitric acid and hydrochloric acid are very strong with pH values of 0; stomach acid has a pH of 1. Addition of a strong acid, such as sulfuric acid ( H2SO4 ) to water makes the resulting solution very high in active acid concentration. This is called an acidic solution.
On the other end of the scale are the alkaline substances, which range from 8 to 14. Common alkalis are seawater (pH 8), household ammonia (pH 11), oven cleaners (pH 13), and the very strong alkali, sodium hydroxide (pH 14). The addition of a strong base or alkali material such as sodium hydroxide(NaOH ) to water makes the resulting solution very low in active acid concentration. This is called a very basic or alkali solution.
In between these two extremes is a pH of 7. This is the pH of pure water. Water, which is neither very acidic nor very alkali, is said to be neutral.
Technically, the scale actually refers to the concentration of positively-charged hydrogen (H+) ions and negatively-charged hydroxyl (OH-) ions in solution. More hydrogen ions than hydroxyl ions makes an acidic solution, while an alkaline solution contains more hydroxyl ions than hydrogen ions. The pH scale is a logarithmic one, meaning that each pH unit has 10 times as many hydrogen ions as the unit above it. So, at pH 4, there are 10 times more hydrogen ions than at pH 5 and 100 times more hydrogen ions than at pH 6.
Acidic cleaners can etch calcite stone (marbles, limestones, and travertines), creating dull spots that remain even after careful cleaning. Harsh alkaline cleaners can prematurely strip sealants out of sealed stone, making them suseptible to staining and discoloration. They can also dull down the polished finish of a stone installation over time. pH neutral stone soaps are effective for routine cleaning and contain no ingredients that will etch, or dull stone over time.
The following table will give you an idea of the pH values of common substances:
pH Value
Stomach acid 1.0
Lemon Juice 2.4
Vinegar 2.8
Orange Juice 3.0
Tomato Juice 4.0
Black Coffee 5.0
Detergent 6.5
Milk 6.8
Blood 7.2
Baking soda 9.0
Domestic Bleach 11.0
Household Ammonia 11.0
(From General Chemistry by Brady and Humiston, 1986).
|
