Norton White Tile Method

Want to make black images that are fused into the glaze of white tile (or into clear glass) with your CO2 laser? The Norton White Tile Method is what you are looking for…

Chemical premise

• A thin coating of rutile TiO2 is deposited on a glazed ceramic and/or glass surface.
• Application of heat using an IR or diode laser converts the anatase crystal form into the anatase crystal form, while simultaneously fusing it into the glaze oxide
• This results in a black (anatase) marking which is fused into the glaze and thus resistant to photobleaching, scratching, etc. (in contrast to methods in which one engraves the surface of the tile to form defects, rubs in dye, and then seals the surface)

Inspiring articles

• rschoen describes the use of a 2 parts water: 1 part Elmer’s glue: 2 parts TiO2 powder (with an optional few drops of food coloring dye) applied by brush in one or two coats. He uses an ordinary lens and draws vector images on glass.

• Omtech describes the traditional Norton White Tile Method; they recommend the use of a compound engraving lens to get smaller dots. Specifically they (specific for the manufacturer?) state that a “universal focal lens (typically 1.5” or 2”) … create a typical dot size of around 0.25mm when focused … approximately 100dpi. … [A] Compound Engraving Lens… can achieve a dot size of 0.1mm — capable of engraving a 254DPI image” (comment: this seems like a nice-to-have, not need-to-have). They also recommend either using spray paint or using an airbrush to apply “2 tablespoons of [TiO2] powder with 4 fl oz of ethanol and shake thoroughly before and during application”. They recommend two coats, applied after rotating 90 degrees.

Commercial sources

• Cermark sells laser marking sprays and paste for glass and ceramic but they are a bit pricey

• Laserbond Tech also sells a marking spray for this purpose again, quite pricey ($78/can )

  • Their instructions are quite helpful. Key is that you want to apply an even and smooth goating, just about enough to cover a black marker line on a sheet of paper. Recommendation for IR lasers on glass is ~10 Watts at 30% speed and 300 DPI, and recommendation on ceramic is 15 W, 50% speed, 600 DPI

Around the web

• Corvus Moon recommends using Rustoleum White Inverted Marking spray—he claims is water soluble. (Comment: This is not what Rustolem product sheet says…but seems well attested in other forums) Jeffrey Court white bathroom tile from Home Depot or Mohawk Bathroom tile from USA. (The glazes work well). Use 90% isopropyl alcohol to clean the surface of the tile, then spray 3 light coats of the marking spray. Let dry for 15-20 minutes (coating is chalky, don’t touch the surface). imag-r.com can be helpful for dithering in a way that is appropriate for Norton While Tile method. Wash with soap and water. 19% power on a 10W laser.
• Lasers and Saws recommends. 50% (by volume) isopropyl alcohol and TiO2 powder in a spray bottle. You want a very fine mist. Use glass cleaner to clean the tile. Then spray and let it dry for 5 minutes. Apply more coats until it is dry and flat. Run a power scale test. Then just clean it with a toothbrush and water.
  • In a subsequent video he instead recommends 3 parts water, 1 part elmer’s glue, 1 part TiO2 powder, a few drops of food coloring. Shake it up in a jar. Apply with a foam brush, pop bubbles using a torch. -Benson Chik also attests to the 3:1:1 ratio, optionally with a drop of dish soap.
• RDWorks found that a 1/3 to 2/3 (by volume) TiO2: Isopropyl alcohol mix airbrushed nicely. This is also affirmed by James MicGinty, who found that a 1:3.5 v/v TiO2:Ethanol solution airbrushed nicely. There are some nice examples of what this looks like in a discussion thread
• Ron Clarke method. 2 Tablespoons H2O + 100 mL PVA + 1 Tablespoon TiO2. (Covers 12 7”x7” tiles. Paint clean tile by brush and let dry. 1000 mm/m and 80% power on a 40W diode laser at 185 DPI. )

Materials

• Inexpensive white tiles, e.g., 4x4 inch - $11/case of 100 ea (caution: weighs 36 lbs)

Either:

• Rust-Oleum white marker paint - $10/ea [SDS]

Or:

• TiO2 powder - $10/ 100 grams, pop over to Kremer on 29th Street btween 7th & 8th Ave. Open M-Sa 9-5pm . SDS or you can buy some food grade TiO2
• PVA-based glue (i.e., Elmer’s Glue)
• Water
• Foam Paint roller or brush

Procedure

1. If preparing your own paint: Combine 3 parts water, 1 part Elmer’s glue, 1 part TiO2 powder in a glass jar. Seal the jar and shake well to mix.

2. Clean the surface of the tile with 90% isopropyl alcohol

2a. Apply two thin coats of TiO2-based paint. If spray painting, keep the recommended distance and rotate the tile between passes. If brushing, ideally you want to use a brush as wide as your tile (to minimize overlaps, brush NS+EW and then make a second pass.). The important think is to get a uniform layer and avoid brushstrokes. Let the paint dry. (5-10 minutes for spray paint, 15-20 minutes for Elmer’s glue based approach)

1. Laser engrave a test pattern

2. Clean the surface under running water, using a toothbrush.

Safety considerations

• Michigan State University has an extensive webpage on TiO2 safety.

• TiO2 is not chemically toxic (it is used in powdered sugar, cosmetics, and sunscreen), but the powder is a potential inhalation hazard. This is generally from chronic exposure of large quantities, typically in an industrial setting may be weakly associated with lung cancer; however other large scale epidemiological studies do not suggest the existence of carcinogenic effects from chronic workplace explosure.. Mitigation: Use pre-made paint or take precautions (careful transfer, consider use of N95 respirator mask to reduce exposure) when preparing your own paint from powder.

• The use of water-based solvents for depositing the TiO2 on the surface avoids the risks associated with lasering paints.
• The amount of TiO2 vaporized during the laser process is minimal.
  • There is no specific metal fume toxicity associated with TiO2. see reference article on metal fume toxicity
  • Metal fume fever is typically associated with Zn, Al, Mg, Cu, Cd, Pb
  • (There is an isolated report of acute titanium toxicity associated with titanium ethanolate exposure, but this is a highly reactive liquid reagent, not really relevant here.)
• Cleaning the surface with isopropyl alcohol has typical ventilation, skin contact, and flamability hazards. NJ Health
• Application of spray paint has usual associated ventilation safety precautions.
• Use of laser engraving has usual associated safety precautions. Tile substrate is non-flammable.
• Post-engraving cleanup is conducted in water. There is no contact toxicity of TiO2, but it is recommended to use gloves when washing the surface.

Variants

• There are isolated reports of doing this with other metal oxides, such as iron oxide (which creates a red color). An article by Rachel Clark in Ceramics montly (2017) (also: Archive) describes doing this by mixing the metal oxides with isoproyl alcohol “to the consistency of heavy cream” and applying to the surface with a roller. (Unfortunately the internet archive does not preserve the images). The unfused oxide powder can be brushed off for re-use. The image captions describe use of red copper oxide, black iron oxide, black copper oxide, cobalt oxide, nickel oxide, green chrome oxide, red iron oxide, and black nickel oxide.
  • Obviously some of these present new potential metal vapor hazards to reassess, although the iron oxide variants seem fine.
  • Shades of glazing chemistry…
• Also cool: Powder coating color fill (works on wood, acrylic, class, clay etc). Official Trotec video, with parameters for Speedy 300 80W laser. Premise is that you engrave a shallow trench, fill in the powder coating, and then run a pass which melts the powder coat where desired. This can achieve bright colors. It’s a fundamentally different process (organic versus inorganic)…but the color fill is reported to be stable for up to 40 years.
• Also cool: Laser foil. Fundamentally just an adhesive mylar coating, but can look cool. Can be applied to wood or acrylic. Video shows settings.