Coatings And Mural Painting For Tile

The first test that I did was on a couple of old tiles from the airport. The facility I'm working on right now is the Portland International Airport and the project is an extensive remodel of 17 restrooms on various concourses and in the public areas. The tiles that need to be replaced are no longer being made and so far no existing tiles are available in colors that match or even come reasonably close to the existing.

I could just buy some bisque from either Dal Tile or American Olean, formulate a glaze that is the right color with a matte finish, and then have a local tile manufacturer fire the tiles for me, but the lead time would be too long. I have to be able to produce the replacement tiles pretty much on demand with a turn around of 3-4 days. The tiles have to be able to withstand commercial cleaning, and be somewhat resistant to graffiti, although most of the tiles I'm replacing are down at the floor (bottom course) and at the ceiling (top course), so fortunately that's not quite so important as an accurate color match.

There are two products that I am currently testing for this project. Vitrea 160 and Porcelaine 150, both made by Pebeo. Both are thermo hardening water based paints. Vitrea 160 is hardened at 325 degrees for 40 minutes while Porcelaine 150 is hardened at 300 degrees for 35 minutes. The two products are not compatible with each other and neither seems to play well with water. Pebeo makes mediums and thinners for use with each product and Vitrea 160 also has mediums and treatments that produce frosted and crackle finishes. Porcelaine 150 can be mixed with a special medium to produce a matte finish. While Vitrea 160 is made for use on glass, I also see that it has good bonding properties with glazed ceramics. So far the two tests I've conducted used starndard grade wall tile from Dal Tile.

Status as of 6-6-2008

Test - 1
Substrate - Dal Tile standard grade wall tile, matte glaze. One section was left as is, the other was sanded with #80 sand paper at high speed with a standard polisher used in the stone fabrication industry. Both surfaces were cleaned with water and wiped dry.
Application - Undiluted Porcelaine 150 was applied with a metal rod to a uniform thickness and allowed to dry indoors at 70 degrees F. for 24 hours, then baked in an oven at 300 degrees for 35 mintues.

Observations -
~ Product was low odor and easy to work with. It flowed eavenly over the surface of the tile and appeared to be moderately self leveling. Colors do not appear to change much if at all between application, drying and baking. Color is rich and opaque where heavier application but transparent to translucent where thinner application was allowed in test sample.
~ Product cleaned off of rod, which was smooth, easily with a paper towel.
After drying but before baking, product was soft enough to take an impression from both cloth and finger print but these impressions dissapeared during baking. Texturing by stamping will probably not be possible, however I will be doing some other texturing tests using other techniques.
~ After baking the product was extremely hard and I am currently in the process of challenging both the bond and the product's surface resistance to chemical and mechanical attack.

Challenges -
Abbrasives
~ Scrub wet and dry with plastic fibre pad - Little or no scratching at 5-10 lbs. pressure.
~ Razor blade - A small section of the material was shaved off of the surface of the tile on both the abbraided and factory surfaces. This was fairly difficult and would have been even more difficult if the entire surface of the substrate had been coated. Upon exposure the substrate surface showed staining by the product indicating possible penetration of the product into the surface of the substrate's original glaze.

2. Chemical
~ Glass Plus (brand) - No change in surface finish or integrity of material or bond after 30 minutes continuous exposure.
~ Planned are standard cleaning chemicals as well as alcohol, xylene, acetone, laquer thinner, Goof Off (brand), citrus based cleaners etc..


Test - 2
Substrate - Dal Tile standard grade wall tile, matte glaze. One section was left as is, the other was sanded with #80 sand paper at high speed with a standard polisher used in the stone fabrication industry. Both surfaces were cleaned with water and wiped dry.
Application - Undiluted Vitrea 160 was applied with a metal rod to a uniform thickness and allowed to dry indoors at 70 degrees F. for 24 hours, then baked in an oven at 325 degrees for 40 mintues.

Observations -
~ Product was low odor and easy to work with. It flowed eavenly over the surface of the tile and appeared to be moderately self leveling. Colors do not appear to change much if at all between application, drying and baking. Color is rich and opaque where heavier application but transparent to translucent where thinner application was allowed in test sample.
~ Product cleaned off of rod, which was smooth, easily with a paper towel.
After drying but before baking, product was soft enough to take an impression but these impressions dissapeared during baking. Texturing by stamping will probably not be possible, however I will be doing some other texturing tests using other techniques with this product as well as the Porcelaine 150 product.
~ Before baking the surface was challenged by imprinting by stamping with a piece of #80 silicon carbide sand paper. Bits of grit and small amounts of dust undoubtably became embeded in the surface of the product during this process. After baking an unexpected texture similar to orange peel in laquers was observed. I'm unsure if this was due to the surface contamination from the stamping or if there was some moisture in the buscuit of the tile that may have come up through the abraided section of the tile's original glaze that caused this. Further tests will have to be conducted to resolve this issue. I don't believe that the texture was caused by a reaction to the tile's original glaze as the texture is only present over 30%-40% of the test area. The rest of the test surface is smooth and as expected.
~ After baking the product was extremely hard and I am currently in the process of challenging both the bond and the product's surface resistance to chemical and mechanical attack.

Challenges -
Abbrasives
~ Scrub wet and dry with plastic fibre pad - Little or no scratching at 5-10 lbs. pressure.
~ Razor blade - A small section of the material was shaved off of the surface of the tile on both the abraided and factory surfaces. This was fairly difficult and would have been even more difficult if the entire surface of the substrate had been coated. Upon exposure the substrate surface showed staining by the product indicating possible penetration of the product into the surface of the substrate's original glaze.

2. Chemical - No challenges yet but planned are standard cleaning chemicals as well as alcohol, xylene, acetone, laquer thinner, Goof Off (brand), citrus based cleaners etc..

I'll post updates here as I do them.

Joanne Rigutto

SPECIAL NOTE! - This post is part of a larger discussion on doing mural work on tile both on new tile and on existing installed tile. To read more see the thread over at Wet Canvas! - HERE