This is 5% doing, and 95% mucking around and finding out. You *will* have failures, and that’s both ok and normal. Get yourself some waste material, the cheap stuff, and see what happens.
In this article, we’ll cover titanium dioxide (Ti02) as it relates to diode lasers. What exactly is Ti02? It’s a natural substance that one finds in many modern products. Sunscreen, makeup, food, pigments, and paints. It’s not considered hazardous, doesn’t ignite, has no smell, and typically comes in powder form.
That bit about use in paint is of particular interest to folks with laser engravers. There is a technique for white ceramic tiles called the Norton White Tile Method, which utilizes white spray paint applied to the tile and then lasered to produce permanently bonded black images on the tile. The tile is then cleaned with chemicals to remove any excess paint, finishing the product. It’s a widely known technique that works very well, and it works specifically because of the concentration level of Ti02 found in white spray paint. So that got me thinking, can we skip the middleman? To find out, I snagged a bag off Amazon.
From what I understand, which could be totally wrong, is that flat white spray paint has a concentration of 30% Ti02 (measured by volume). Being careful not to breath in the dust, I mixed up a batch, two thirds water and one third Ti02. Because Ti02 is white, and applying it to a white tile might make it difficult to see if an even coat was applied, I added a few drops of acrylic paint to give the concoction some color. The consistency was about that of 2% milk, just a bit thinner than I usually use in an airbrush, but workable by lowering the pressure on the compressor. While most of the time I used the airbrush to apply the mixture, regular brush application worked as well. For some, this might be the best course. The filters in my mini airbrush booth filled up quickly and needed replacing. All set, it was time to experiment.
Ceramic Tile
Well, I couldn’t very well start with any other material, could I? Aside from white tiles, I also prepared black tiles, just to see. As is my habit, first run was a power speed test on the white tile, ranging from 1000mm/m to 11000mm/m, and 10% to 100% power. 20min or so later, I was washing the tile clean with plain old water, removing all the excess.
What I found was good. Very good. A nice gradient starting at 30% power and moving up. Blueish, gray, and black. Even the high speeds were still getting black in the mid to upper power combinations. Strangely, 20% power didn’t do much of anything, (or so I thought). Armed with the data from the test, I ran a few photos, which came out good. Next, some vector images with multiple layers, each layer with different power/speed combinations, matching different colors from the power speed test. Again, success.
Switching over to the black tiles, I figured I might get a faint, flat, image if I was lucky. A ghost image kind of thing. I figured wrong. While I didn’t get a vibrant color, what I did get was a metallic looking image, plain to see. Like when Dry Moly is used, but more silvery than Moly’s slight gold tone. Using the combinations for light grays produced more distinct images, more vibrant, but not brilliant. With that, I was ready to try another material, to see what else I could use Ti02 with.
Glass
Glass is kinda similar to ceramic, and I could have cheated by just using the results from the power speed test on ceramic. But as it happened, I’d just finished doing a comparison of galvanizing spray vs Dry Moly and tempera paint (galvanizing pray lost by a long shot) and had enough free space on a glass sheet to run all the same tests. Generally, folks are looking for black or white on their glass, and I guessed that maybe a setting would turn up the black like on a tile.
Here is where I got a few surprises. The power speed test gave me another wide range of colors, wider than before. I got the black I was expecting, but I also got white. Like white white, not frosted kinda white. Right down in the lower left quadrant, at one particular power setting, was white. The image test I usually run for glass had the same results, confirming that the power speed test results were not a fluke. Subsequent tests, using yet lower speeds showed that the white continued to appear, meaning that it could be used for rotary work without a problem.
Ceramic Tile (Again)
So….if I could create white on glass, why didn’t I see it on the ceramic tile? Duh….because the one I did the power speed test on was white. I’d been lazy and not done it on one of the black tiles. Going back, I ran the power speed test on one of the black tiles I’d prepared. Bam! White, just where I expected it to be. And, the colors overall were slightly different than those on the white tile. Creating multi colored designs on black tile was a go, as were photos.
Wood
Out of curiosity (typical), I dusted a bit of scrap plywood with the solution and let it dry. Note, it picked up a hint of the paint color I’d added to the solution. Like when using borax or baking soda solutions on wood, the results I got were darker than what comes with bare wood. This opens up a whole other realm, one which I’ve yet to explore further.
Wrap up
Slate is on my list of materials to try, as well as others as they come along. But for now, glass and ceramic tile both show excellent opportunity for creativity and unique product offerings. I did not include images of my power speed tests, as my intention is to get you, the reader, to develop the habit of running and using these tests to expand your knowledge and abilities. I’ll show you the possibilities, but it’s up to you to make those possibilities into reality.
Remember not to snort the dust, and wash your hands often. Shake your solution well before using. If using an airbrush, have good ventilation/filtering, maybe even a mask. Don’t leave the solution in your airbrush overnight, else you’ll likely need to do a complete tear down and cleaning.