This is Fun... ceramic tile engraving using Nicky Norton method

Having talked with @RoughDraft40 about the Nicky Norton Method of laser engraving a ceramic tile permanently, I started using the method today. Apart from lots of tiles and a laser, I needed to obtain some white spray paint and some acetone.

Step one - Method: The four tiles which I prepared were wiped over with acetone. I understand that ceramic tiles may have a coating that is resistant to paint. Cleaning the glazed surfaces of the tiles with acetone was very quick and it dried rapidly. I then sprayed the tiles with a coat of Rust-Oleum all surface, matt paint which was described as Flat White in colour.

The tiles were touch dry in 30 minutes and the paint can be re-coated after one hour. Re-coating was not necessary and I left the tiles to dry completely for 24 hours. The image was grabbed from Google as a screen grab and left as a PNG file for Lightburn.

My settings follow: Feed rate 250mm at 100% power. The image was a line drawing so I did not need much resolution and I set the interval to 0.180 which equates to 141 dpi. The image mode was set to Stucki for high quality dither and more speed than Jarvis. Cells per inch numbered 50 and the halftone screen angle was 22.5° Total burn time was a shade over 3 hours.

Pix:

The tiles were painted with a light coat of paint until they looked to be matt finished.

The laser engraving apart from the paint is as one would normally undertake. There is a faint clouding of the image because the white paint is still in situ.

The completed image looks slightly veiled because of the white paint which still required removal.

Tah Dah! The image was wiped with acetone and the white paint came off very easily. The permanently engraved ceramic surface is still shiny, having been protected by the paint. This method produces a very high quality finish and it is very easy to achieve. I can recommend it as another process to increase the versatility of the Shapeoko CNC machines. I have seen other people suggesting the use of black paint on a white tile. I see no need for it if you want the engraving to reflect the image exactly as it was produced.

Next on my list will be engraving photographic images. I use Affinity Photo and if anyone here does use that and wants to try laser engraving of photographs on tiles, I use a method of creating pencil sketches that may prove useful. I reproduce it below:

  1. Import image [⌘+O] for open or (place) image
  2. Duplicate background image - [⌘+J]
  3. Add B+W adjustment layer (then add that to the newly duplicated layer)
  4. Menu Bar - Layers - Merge visible (or right click for context sensitive menu)
  5. On the merged pixel layer - [⌘+I] to invert the layer
  6. Change the blend mode to colour dodge
  7. Add live filter to newly inverted layer - gaussian blur
  8. Move radius slider to the Right to see and adjust the pencil sketch effect

Mac users will know the [⌘] key.
Windows or Linux users will need to substitute it with the [Ctrl] key.

A brief clip of the laser in action will give some idea of the speed with which the job was engraved.

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Can you describe what is happening? Is the laser charring the paint and fusing it into the glaze?

Thanks.

I have not researched this thoroughly. My intuition is that the matt paint prevents the laser beam from being reflected back from the shiny glaze and this permits the laser beam to stay in place long enough to heat its way through the glaze. Some people are apparently using gloss white paint which makes my hypothesis feel incorrect. Where the paint does take the image, one can assume it has been burnt. Whether that charred paint gets incorporated into the tile glaze in some manner or another, is a question I will leave to the analytical chemists. (alchemists?)

How and ever, the process works and the images cannot be removed by scraping. A very robust image transfer process that is simplicity to implement and no toxic chemical processes required.

N.B! Correction.
The Rust-Oleum paint container sports 3 hazard symbols.

Irritant:

irritant

Flammable:

flammable

Serious Hazard to Human Health:

human-health

Contains: Acetone, Hydrocarbons C9 ~ C12, n/-iso-/cyclo-alkanes, aromatics (2~25%)

I wore eye protection and a FFP3 mask while spraying and that was done outdoors.

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That’s amazing! I’ve got to go the a home store and pick up tiles and spray paint now.

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Just because it looks white (i.e. reflects all visible wavelengths) to the human eye doesn’t mean is reflective at the laser’s wavelength.

I don’t think that’s what’s happening. Whether it’s being reflected is a characteristic of the colour of the paint (the spectrum of light it reflects) more than the surface finish. White paint = reflects the entire visible spectrum. A matte finish just means it’s being reflected in all directions instead of only straight.

I don’t think that’s it either. In your other post you successfully engraved through the glaze, even without the paint.

I think @kelaa is right and the black is just the charred remains of the paint.

Given that, I think you might be able to get similar results by filling the engraving with another material, like powder coat, epoxy or wax. That would also give you greater control, like the ability to select colours.

Though generally true, JTech lasers like the ones @jepho is using are 445nm, which is still within the visible spectrum.

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A bit of addition to this extremely well documented process, is that I made some test patterns at various speeds and power settings. In the process of designing this test toolpath, I included paths that burn the toolpath twice.

What I found was that the 2nd burn made the cut lighter than those with only one burn. I was confused at first, but soon came to the conclusion that some residue of the paint was removed after being deposited on the first burn toolpath.

The residue left after the first burn toolpath could not normally be washed or scraped off.

I was trying a paint that contained excessive amounts of zinc. Perhaps that made the difference.

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Thanks, Brian. I think that the really fine appearance is making me look like I am a much better machinist than I am in reality.

:grin:

A good point, well made. Thanks Jason.

I would have thought a matt finish would change the reflectiveness of the surface, when compared directly with the same coloured surface that was shiny.

Specular reflection from a shiny surface implies that the angle of incidence will result in an equal and opposite angle of reflection. It may also imply that light from a single direction which strikes a reflective surface… a window for example, will appear to be reflected in the opposite direction at an equivalent angle. This may lead the observer to conclude that there is less light available when a surface is viewed from an angle from which the light is not being reflected.

Diffuse reflection implies that the surface is reflecting light at many different angles. It does not make the perceived object brighter because some of the reflection will be lost to the observer’s eye as it heads in directions that the observer cannot perceive.

Yes, however that glaze was matt to start with so there were no specular reflections and that made me think I could engrave the surface directly without having to consider the possibility of laser beam reflection. I also had wonder whether a matte surface could absorb more laser energy because it was not being turned away by the reflective surface.

Yes, there is certainly plenty of room to experiment. Colour may come with dividing a single project into distinct phases and using colours for each phase.

I found that the paint in use had wiped off easily with a small amount of acetone soaked into a rag. The paint contains up to 25% acetone anyway, according to the directions. While the engraved pattern was firmly fixed and impossible to scrape or damage, the paint removal after the burn was a really trivial process.

I noticed something similar on my hexagonal coaster burns. My conclusion is different because I did not use any paints on that project. I thought that it was because the second burn resulted in more heat being applied to the clay. The lighter colour was possibly caused by the additional heat application which may have resulted in a change to the structure of the clay. q.v.

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+1

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There will be some small difference. For example if your matte surface is a loofah, a bunch of the light will just be bounced around and reflected inside the holes, so it’ll absorb more. A painted tile should be less extreme but depending on the texture, some of the reflected light might hit the surface again, absorbing a bit more energy.

In this case though, I really don’t think it’s making a difference. I think any material that turns sticky and black when hit with a laser will probably work.

I wonder how powdered sugar would go… it should smell better than burned paint :wink:

Yes. I can see that is very likely. I would be very interested to understand how the charred paint is fusing itself into the glazed surface.

Molasses sugar would at least smell sweet… tastes great too.
:wink:

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This is interesting.

It is certainly possible to use lasers to heat up carbon particles to glowing hot temperatures (see for instance laser induced incandescence, a soot measurement technique employed by flame and engine combustion labs).

If the paint is just mainly a carbon source that is convenient to apply a certain thickness evenly, then the color should not matter. But I don’t suppose it is impossible that it confers other properties (such as making off-gases that shield the melted zone, akin to stick welding), or that the TiO2 present in say white paint is helpful to seal in the graphititc carbon. I wonder if we an get the pigments to embed as well. Something with Fe2O3 should give a red tint.

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Jeff - beautiful results! I like the design.

I am by no means an expert on laser marking, but my understanding of using marking materials applied over the substrate is that you are bonding it to the substrate using the energy of the laser (and possibly thermo-chemically altering the material depending on its composition and the lasering details). CerMark and TherMark are two popular names in laser marking materials. This page has a good description of how it works:

https://www.engraversnetwork.com/how-it-works/

Basically, you have tiny glass particles and pigment particles in some type of carrier solvent. Apply to substrate, zap with laser, and now you have a super-thin coating of pigmented glass bonded to your substrate in specific areas.

Assuming something similar but slightly different is happening with the paint. Some sort of curing / carbonizing / bonding.

I saw someone mentioned zinc-containing paint. I would avoid that at all costs - zinc fumes are very dangerous. Even with regular paint, I would still recommend the use of a respirator with suitable cartridges and a proper fume extraction setup with adequate fresh air intake.

That goes without saying in just about anything that gets “burned.” I don’t know why some people do this inside their homes. Fume extraction is never 100%.

Thanks, David. I think that for a first shot at this technique, I have been falsely made to look much better than I really am.
:grin:

I guess this is correct because there is no doubt that the design is bonded to the tile substrate.

This feels like it may well be correct but my own ignorance is not providing me with any additional help to understand this phenomenon.

Noted. My respiratory protection is FFP3 level and the goggles are all encompassing. I painted outside while wearing the PPE and during the laser operation I kept my P3 respirator on while wearing laser goggles and safety goggles. To assist the process of self protection, I also sat about 6 feet away from the burn area.

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Tex - it sounds like you have a good handle on things. I get tickled when I see the Glowforge commercials and they’re showing it being used in a living room like it’s an inkjet printer or something. We have a fully-enclosed Epilog laser at work and it has its own roof-mounted exhaust/extraction system with 4 inch ducting. With the zinc, I don’t think it would have any beneficial properties in a marking material. Zinc boils around the melting point of brass (907 C / 1665 F), which is relatively low.

Jeff - I keep organic vapor cartridges on my 3M respirators along with prefilter pads. They do a good job with general dust, paints, and solvents. If I’m going to do lots of grinding or welding, I will break out my supplied air setup (a Breathe Cool unit adapted to a 3M 7502 facepiece). It sucks a little being tethered by the hose, but having a constant supply of nice cool fresh air to breathe is hard to beat (especially when it’s warm outside).

In addition to keeping people safe, having good extraction can help keep your laser’s optics clean. If you can set up a horizontal airflow across your workpiece / machine (assuming your laser is pointing downward), that can help keep fumes / smoke from rising up and ending up on the lens of your laser or other portions of the module.

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