Limestone, Marble, travertine & onyx stone surfaces are easily prone to etching from soft drinks, wines, fruit juice and similar beverages, this due to the fact that natural stones contain calcium carbonate hence vulnerable to acidic attacks.
Once acidic liquids come in contact with calcium carbonate in the stone, the liquids literally dissolve the surface polish hence creating dull spots, and these dull areas are typically called an etch. The more acidic the liquid, the faster and deeper the etching occurs, and in the case of bathroom wall and floors around the showers drains and vanity, these dull spots, etched lines and discoloration are caused by regular runoff of diluted toiletry products.
In surrounding areas near the toilet bowl and urinals, deep etching is usually caused by urine residues and toilet cleansers that contain phosphoric acid. An etch sometime can be confused of being a stain, just like a scratch on stone surfaces, it changed the surface structure of the stone, and the effect appears to be light, dull and discoloration.
I often get clients asked me if they could actually re-polish an etched mark? My answer as follow:- if the surface etch is minimal and not very deep, using polishing cream or powder and a bit of elbow grease will usually polish up the surface to a satisfactory level. However, if the etched mark is much deeper, the etching shadow still be apparent underneath the polish even though the surface has been polished up. Therefore, sanding and resurfacing the stone is necessary, this usually done by using various grits of diamond discs and powders, Due to different type of stone surfaces behave differently to the polishing process, this type of work is usually done by a professional polisher, the main aim is to achieve uniformity, shine, colour and clarity. In regard to scratches on countertops, vanities and floors, the above process applies and required hand and floor polishing machines.
Is there any sealer will stop the etching effects? Surface coating such as polyurethane, epoxy and acrylics can form a plastic layer to stop the etching, however these surface coating do not have a good adhesion on the stone surface, and we often seen delamination occurs within weeks, therefore the only sealer to use is a good quality penetrating sealer. It is interesting to note that penetrating Sealers cannot stop etching as they cured beneath the stones surface, and does not form a physical barrier between the acidic liquid and the stone. Then you may ask, why do we need seal the stone if the penetrating sealer will not stop etching either? Although calcium based stones prone to acid etching, they are also easily scratched, and porous in the cases, and they can be stained by foods and oily substances. Therefore, applying penetrating sealers will reduce the stones porosity thus providing stain resistance, and provide ease of cleaning and maintenance.
If you found etched marks and scratches are too deep and beyond the DIY repair kits, it is advisable to contact a professional stone polisher in your area to rectifying the problem, If you are in Sydney, why not contact us on 0425 266 839 or visit us on http://www.thewowfx.com.au for a quotation.