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Most people don't know how a sealer works and with so many opinions flying around the internet, it's hard to know what to do. Not to worry! A couple simple tests will tell you what kind of stone you have, how to clean and care for it and if sealing granite countertops is necessary. Determine Your Stone Type and |
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Granite is the stone of choice for use in the kitchen where all kinds of substances will come in contact with the countertop.
Some granites are more absorbent than others (not good) and some "granite" is actually mixed with calcite (like marble) and the surface will corrode or "etch" when exposed to acids like lemon juice, coffee, alcohol, salad dressing, etc. (not good).
Etching has nothing at all to do with sealing granite countertops or marble or travertine. Sealing will not prevent this.
It is a chemical reaction between the acid and the calcite that physically alters the stone, which is especially noticeable on polished surfaces.
All marble, travertine and limestone will etch and most are also prone to staining, which is why these stones are typically not recommended in the kitchen... unless you are willing to let them age naturally... spots and all.
But some of these stones are very dense and won't absorb a thing or stain at all, especially when polished, which helps decrease absorption rates for any stone.
You want a stone that won't do either (won't etch or stain) for the kitchen. That's granite.
So, this test is most useful to determine the best granite for your kitchen, wet bar or heavily used bathroom were lots of potions and lotions could be a problem.
NOTE: Perform this test on samples chipped off the exact slab you are considering for installation.
Also, this test could damage the surface polish of calcite-based stones, so if you are trying to determine the nature of a stone already installed, perform this test in an inconspicuous spot (in a corner or a spot that is always covered by an appliance, etc.)
If all you are trying to determine is whether sealing granite countertops or any other stone is necessary, you can perform the "Lemon Juice and Oil Test" using water. The reason for the lemon juice is to determine if your stone can handle contact with acidic substances. Of course, if it can't you don't want it in the kitchen... and the oil is very noticeable if absorbed.
So, drip a puddle of water on your countertop, note the time and observe.
If the puddle darkens quickly, then sealing granite countertops is required... annually for 3 years is not a bad idea and be quick about wiping up spills.
If it takes 3 or 4 minutes to darken... again a good impregnator/sealer should be applied, but re-sealing every 3-5 years should be fine (possibly longer... re-test when the time comes) and stains won't be a big issue unless something sits for a few hours.
If the puddle doesn't darken, then you have a bullet proof stone that is next to impossible to stain. Sealing granite countertops in this category is really not necessary, but for most people a coat of sealer just adds peace of mind.
Client "peace of mind" is the primary reason many/most professionals recommend applying granite sealer when in doubt or even if it really isn't needed. It's a fairly easy procedure and not expensive, so why not in most instances.
For most granites, applying a sealer even when not needed won't present a problem....
However, some dark granites (especially blacks and greens) are very dense and if a sealer is applied, it just sits on the top and can noticeably dull the appearance. If this happens, the sealer must be stripped and possibly the surface re-polished... an expensive pain.
If you have a dark, dense granite and need convincing, let a drop of oil sit on your sample overnight. Wipe it off. No spot? You will never stain this countertop.
If you notice a stain, wash it with a little soap and hot water and dry it. Stain gone? Your tops are essentially impervious to stains, but they will probably take one coat of sealer without issue.
Personally, I wouldn't bother in this case since the sealer is improving the stain resistance so minimally that it's not worth even the small chore and expense of sealing.
There ya go! Now you know the real test for sealing granite countertops and have the knowledge to make the best choice. Good luck and have fun!
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