I finally got a chance to test powdered TiO2 and I’m pleased with the result.
On the advice of others, I bought food grade powder and made a mixture of:
3 oz very warm water
1/4 tsp Borax
1/2 oz TiO2
Mixed the borax with the water and shook until the borax was dissolved. About ten seconds.
Added the TiO2 and shook it in a covered jar until well blended. Only a few seconds.
Poured the mixture into a paint sprayer similar to the one referenced by @Hank above
and did some test sprays on some cardboard until the coverage was fairly uniform (I needed to shake the sprayer to keep the TiO2 mixed every 8-10 seconds).
Then I tried the solution on two different substrates:
- Flat white tile (not glossy)
- River Rock
In both cases I preheated the material to 80C just before spraying so that the ‘paint’ would dry quickly in place rather than running off. This worked well with the tile making a very uniform covering. It worked ok on the stone, but I think an airbrush would work better so you can uniformly cover the exposure area without wasting ‘paint’.
Then I tried a range of exposures on the tile. My laser is a ‘30W’ diode that I’ve measured to 5.5W @100% power. In the photo below, you’ll see two set of exposures, one set ranging from 5% to 70% power at 1000mm/min and the second set ranging from 5% to 70% at 500mm/min.
The triangle infill is using a fill method with 0.25mm line interval, the outline is a simple one pass vector at the stated power/speed.
The rock was exposed with a fill/line cut style at 1818mm/min, 100%power, 0.125mm line interval for the fill, 909mm/min 100%power for the outline.
Here is the rock as painted, exposed before cleaning, final after cleaning:
While the exposure is easily visible, a lighter stone would be much better.
Finally a word about cleaning. EASY! Soap and water on both the material and the sprayer. In fact, I don’t think I even used soap on the sprayer. Just filled it with plain water, shook it up, sprayed it out, and did this twice. Couldn’t be easier!
In Summary, I think this is a winner!
Next steps, try a photo…