What Sealers Actually Do

Sealer is a term used by stone craftsman to describe a stain deterrent that is applied to natural stone is "sealer". It's a general term that most consumers can relate to, and understand why it needs to be applied. In actuality the correct term is impregnator, however impregnating sealer, penetrating sealer seem to be used interchangeably. The name of the substance pretty much explains what it does. It penetrates into the stone and seals, but it seals without clogging the pores like a topical coating does. Instead an impregnator merely coats the pores of the stone allowing moisture vapor to escape, and letting the stone breathe. I know I know this has been said a million times, and most restoration professionals could recite it in their sleep, but do they actually know what occurs to make the impregnators work? Well in most cases only partially.

When a stone is impregnated properly what should the result be when liquid is placed on it? It should bead up, but why? Many would say it's because of the resins or solids in the particular impregnator, and they would be partially correct. What is the rest of the answer to complete the puzzle? The answer is in your chemistry books. You see Most liquids have a molecular make up that is positively charged, and most natural stones are negatively charged. The impregnator induces an ionic exchange which causes the surface of the stone to take on a positive charge. If you remember playing with magnets when you were a kid ( or maybe just yesterday lol) you'll remember that when you place the negative near the positive - smack they would attract - like liquid and stone. However if you placed the two like charges near each other you could slide them around the table all day and never get them to connect - like liquid beading up and rolling around on an impregnated natural stone.

So as you can see there is a little more that goes into the science of impregnators than just the delivery system, size of the solids, resins, oh and scent.



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Christopher Soderlund
Stone Specialist

Boston Area

(508) 734 - 0435

Cape Cod

Give us a call to have your natural stone professionally evaluated today.


The Stone Repair Network is dedicated in providing quality restoration, repair and maintenance through a network of stone repair professionals. Our network is committed to the education of both the consumer and the industry in the advancement of stone restoration.

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Case Study 1 & 2

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