Protective Wax on Ceramic and especially Porcelain Tiles

For many years the Spanish have put wax in-between both their ceramic and porcelain tiles. I have been asked on many occasions why they do this. Many folk believe the reason is because the glazes are too soft and will scratch easily. Their conclusion being that Spanish products are lower quality than their Italian competitors. However this is not true and is not the reason for the wax.

Glaze is glass and one of the easiest ways to scratch glass is to use glass. When tiles are placed in a box the resulting shearing during transit can easily cause minor scratching of the glaze. This is further exaggerated by the way tiles are made. It is not commonly known but ceramic and porcelain tiles are not made totally flat. If you ever see an old Victorian glazed tile or some of the more ancient Chinese or Italian ceramics you will often see that the glaze has a fine network of cracks. This is called crazing. It occurs because the glaze does not “fit” the body. The natural rate of expansion and contraction of the ceramic body is too great for the glaze. The glaze having little to no ability to expand simply copes with this by cracking. In contemporary ceramic chemistry the fit of the body and glaze is formulated so this does not happen. Part of this control is achieved by firing a ceramic body that is under slight compression. Being under compression, when the body is installed and gains moisture it simply expands to an extent the glaze can accommodate and not crack.

Another result of having a body under compression (sorry for the long digression but it was required to fully explain things) is when tiles are stacked in boxes they no longer sit flat. They actually contact only on several high points making scratching much more likely. It is this problem and a policy of wanting to get products (especially glazed and highly reflective finishes such as polished porcelain) to market in the “best” condition that made the Spanish apply wax in-between the tiles. The Spanish apply the wax using a spot technique so that each tile ends up having 3-4 pieces of very thick wax. This results in no contact between tiles and hence complete protection against surface scratching. By using small thick pieces of wax removal is easy because it cannot bond to the tile to any extent due to this thickness.

In recent times we have seen another ceramic manufacturing region turn to the use of wax to protect the tile surface during transit. Many Asian factories, especially Chinese, now apply wax. However they use a completely different technique. Instead of using thick spot fixed wax pieces they apply a thin coat of wax over the entire surface of the tile. The main reason for this is they see the wax as not only transit protection but also protection for the tile during installation and grouting. This seems like a great idea. However it unfortunately creates several problems that have not been anticipated by the manufacturers.
The wax is very hard to remove and in some of the very porous porcelains hinders the application of any protective penetrating sealer.

Why is the thin wax coating hard to remove? When the thicker wax pieces are spot applied the exaggerated contraction of the thick hot wax results in a sufficient but inevitably poor bond to the tile surface. The poor bond makes it very easy to remove the wax. In fact generally it can be removed by hand without the use of any chemicals. In contrast the very thin wax coating does not contract much at all resulting in a very good bond to the tile surface. Moreover the wax used by the Spanish is similar to paraffin wax, and has no real adhesive quality where as the Asians use a synthetic wax (similar to those used in synthetic floor finishes), which has quite good adhesive characteristics. So the result of all of this is that the wax used by the coating exponents is much more difficult to remove.

So how do you remove the thin wax coatings? As I have already mentioned these waxes are usually synthetic. They can in many cases be chemically removed using alkaline chemicals. Aqua Mix Heavy Duty Tile and Grout Cleaner is ideal. It must be used full strength for best results. However in some cases alkaline chemicals will not work. Synthetic waxes become much more durable when they are applied in thin section and with heat. In many cases the technique used by the tile factories is a thin application. However it is also quite often applied just after the tile has left the kiln where it is still some 45 to as much as 65 degrees Celsius. The heat makes the already thin coat cure and bond even more aggressively. This not only makes the coat more difficult to remove but also more chemical resistant to alkaline cleaners. In these instances a solvent must be used to remove the coating. Aqua Mix Sealer and Adhesive Remover is the perfect cleaner for these situations.
When working with either an alkaline or solvent cleaner the complete removal of a thin wax coating can be difficult without some type of abrasion. The cleaner will re-emulsify the coating but not completely remove it from the surface. Abrasion helps to remove this final thin residue. The best abrasive to use is one that will not scratch and has some ability to absorb the coating. Aqua Mix Poultice makes the ideal partner to the appropriate cleaner.

The last issue regarding thin wax coatings is how they can affect sealing. Many of the lower cost porcelains have higher water absorption. Coupled with this is the use of a plastic dye to press the body. These low cost dyes not only result in lower compressive strength but also a slightly textured surface. This texture when combined with higher porosity makes the complete removal of the wax coating very difficult, as the coating is more easily trapped. If it is not completely removed the sealer will have difficulty penetrating and bonding to the tile surface. In most cases penetrating type sealers are used on porcelains and therefore having the ability to penetrate the tile surface is a pre-requisite to their performance. The trick is to make sure that the wax is removed and to make an extra cleaning effort when plastic dye tile or textured tile are the issue. The use of an abrasive such as Poultice becomes even more important in the latter case. There is also one further recommendation. In general use a solvent based sealer for tile coated with wax. Wax is a great water repellent and therefore any wax that is not removed will definitely repel any water-based sealer. However a solvent based sealer (such as Pro Solv 10) has a much greater chance of getting through any wax residue missed in the cleaning process as the solvent will dissolve the wax.

In conclusion the advent of wax application to packaged tile is not an indication of poor quality as sometimes originally believed. It is simply a factory trying to transport the tile to site in as good a condition as possible. However the different wax application techniques do require different cleaning methods and chemicals and need to be understood to insure the finished tile performs to its full potential


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