I was told by one fabricator that ALL granite must be sealed. (I specifically mentioned Volga Blue.) I have read where you say that is not true, some do NOT need sealing. My question, what happens when a granite that does NOT need sealing has a sealer applied to it anyway?

 

Dear Gina:

 

“ I was told by one fabricator that ALL granite must be sealed ”

 

Brainwashing at its very best. The “sealing cult” and the amazing ignorance surrounding the stone industry are as strong as ever!

Let's take Volga Blue, for example. That fabricator tells you that ALL granites need sealing.

But does he have even the slightest idea that Volga Blue is a stone (anorthosite) that's related to granite like a cat to a cow?

So, does he want to seal that one too, just because the invoice of the distributor calls it granite??...

And how exactly does he plan to do that, considering that Volga Blue is so dense that it will not absorb one iota of impregnator (that what a sealer of stone is)?

Just sprinkle some on the stone, rub it on, and then remove the residue that was not absorbed by the stone before it has a chance to dry, I guess.

Just like that: just like a pre-programmed robot.

Since not one single molecule of the impregnator will ever get absorbed by the stone, he's actually throwing (hopefully) the whole thing (the residue) in the garbage. Don't you think it would be smarter to throw the unopened bottle of the “sealer” in the garbage without going through the “ritual” of pretending to seal a stone that can't be technically sealed?...

Now you ask, “ what happens when a granite that does NOT need sealing has a sealer applied to it anyway? ”

The answer is, hopefully nothing. Because if for any chance he does not remove the entire thing from the surface of the stone before it has a chance to dry (which is easier said than done), if an invisible film is left behind (which is very probable) and the impregnator used is sensitive the pH active substances (like the majority are), every time you spill something on your countertop you will notice the development of mysterious “ghost water-like stains” that will not come out. And if you ask the fabricator what happened, he won't even know what he's looking at!

If you're doing business with that guy, tell him flat out to go seal his sister's Volga Blue. You'd rather pass his incredibly generous offer, thank you very much!

Please read this to understand better what I mean:

 

DEFINITION OF SEALER FOR STONE

 

For starters, when referred to stone the word sealer is wrong. Well, technically it is not, but the reason why I said that's wrong is because sealers for stone are totally different from any other sealer that most people are familiar with. A sealer is perceived like a topical coating of sorts that's meant to protect the surface of the sealed object from traffic and spills, to produce a finish (polished, or matt, or satin) and to fill all little nicks, fissures and other surface imperfections.

A sealer for stone is none of that – None!

And that is why I said that the word sealer is wrong when referred to stone. The right word is impregnator.

An impregnator is a below-the-surface (of the stone) sort of sealer. It's a product made of two major components: a resin of sorts that could be silicone, siloxane, silane, ester epoxy, alphatic fluorochemicals, acrylics, etc., plus a carrier, that could be a petroleum-based solvent or simply water. The resin is dissolved by and within the carrier.

What does an impregnator do, and how does it work?

The only thing that an impregnator does is reducing dramatically the natural absorbency rate of the stone by somehow filling the spaces between the single molecules of minerals composing the stone, which are known as pores - End of the list of performances. This reduction of absorbency rate (or porosity) of the stone will make so that possible staining agents that may get spilled on the stone will be kept at bay on the surface of the stone for a period of time much longer than if the stone was not sealed.

The way it works is that the solution goes inside the stone, the carrier (solvent or water) evaporates and the resin stays in and cures, thus partially clogging the pores of the stone.

The most important phase of the application of an impregnator is the total and thorough removal of its residue that was not absorbed by stone from its surface, before it has a chance to dry, so that at the end of the sealing job the surface of the stone is as bare as it were before the sealing procedure was started.

The immediate, obvious consequence of that is we're not talking about a coating, but rather an application.

Next, the question is: how does an impregnator go inside the stone?

Quite simply, by being absorbed by it.

So far we've learned a couple of important things: 1. That a sealer for stone only help preventing deeply imbedded stains by delivering a reaction time, which is how much time you'll have to blot the staining agent off of the stone surface before it begins to sink in. (The better the quality of the impregnator in relation to the stone to be sealed, the longer the reaction time will be.) 2. That because of the way it was designed and works it cannot – and in fact does not – offer any protection or improvement whatsoever to the stone surface.

Next, we have now to talk about the natural absorbency of stone.

This side of single-crystal rocks (i.e.: gemstones), every multi-mineral stone is somehow porous. However, while there are stones that absorb liquids like sponges, there are stones that are naturally so dense that no liquid is thin enough to be absorbed by them. The latter types of stones – which are quite a few – can't be technically sealed, because no impregnator will ever stand a chance of being absorbed by them. On the other hand, since they won't absorb any liquid, it is pretty intuitive that they will never get stained.

What is interesting noticing is that while certain stones have an absorbency rate that indicates their ability to absorb liquids (above 0.2%), in fact they don't absorb anything due to their dramatically increased surface tension once polished. For example, travertine is rated at 0.4% to 1.0%. In its rough form it does absorb liquids, though slowly; but if you polish it, it effectively will not absorb a single drop of anything. In fact, nobody ever reported any stain on a polished piece of travertine. (In its hone-finished form, however, travertine may – and just may – absorb something.)

In conclusion, only a certain number of stones can be sealed and, more importantly, the performance of an impregnator is only limited to the reduction of the stone natural absorbency rate if it is – even when polished – above the 0.2% cut off point.

How does the average consumer know if their stone could be possibly sealed without that kind of information? It is quite simple and down to earth: spill some water in a couple of spots of the stone to be tested, let it dwell for 10 minutes or so, wipe it dry and observe if the areas under which the water has been sitting have become (temporarily) any darker than the rest. If so, if the stone is installed in an environment where staining spills are likely (i.e.: a kitchen) the application of a good-quality impregnator is recommended. If not, or if the stone is to be installed where the likelihood of spillage is minimal or nil altogether, it would be a totally useless exercise that will only help to put the kids of the impregnator's maker and its distributors through college.

 

(FYI, Volga Blue absorbency rate is 0.05% to 0.1%. Nothing goes inside that stone! And that, along with its incredible hardness, is what makes it a “better” stone than true granite for the intents and purposes of a kitchen countertop.)

 

Now, how about learning how to take care of your stone on a routine basis? The issue of what you'll be doing day in and day out to your stone is – as it should be intuitive – vastly more important than its sealing (if and when possible and/or advisable) and it's all too often neglected. As you can tell by reading many of this site's postings, you're not likely to get good information about routine care from your dealer or installer. Don't become another statistic! By logging into the Helpful Hints section of our website at:   http://www.mbstone.com/HH_promo/helpful_hints.htm , you will be able to get the short version of our maintenance guidelines at no charge. The full version of it – a 7-page document considered by many as an industry benchmark – is available in pay-per-download format in our Educational Literature section at:   http://www.mbstone.com/literature/literature.htm .  

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Ciao and good luck,

Mauri z io Bertoli

 

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