Powder coatings can be removed and burnt off in the range of 300°C to 450°C.
TiO2 melts at 1,843 °C… Seems to me, it’s rather doubtful it will work adhering it to the powder coating…
If you can heat it up enough you can probably do stainless… Stainless also sucks the heat out of the beam area pretty fast.
This is LBT100 on a stainless mug with my 40W China Blue… Cermark is a similar product… Don’t know how this works with a uv laser…
Good luck
I’ve had some recent success using mustard+TiO2 to deep engrave steel. I’ll finish a write up at some point! Just busy getting ready for LBX 
What kind of laser Billie?
Now I am tempted to start messing with tiles again. Woohoo! Another TiO2 mix!
Was this a lunch time epiphany?
Just had a thought… would Ketchup work better for diode lasers?
What advantage does mustard give you and does ketchup posses some of those attributes so that it may do something similar…
Maybe mayo… then maybe it would smell like fried eggs 
Please start a new thread about it but share a link in this one so we don’t miss it.
I’ve tried mustard for marking metal and had poor results but some have said it worked and this is the first I’ve heard of combining mustard with TiO2. Looking forward to read how your experiences went.
I figured because it was red, it would be good for diode lasers. Might smell better too.
Pardon my ignorance, but does graphite bond to glass under a laser…?
I don’t know, but I don’t want it to, it’s just so you can see the white paint on the white tile. 
I’ve found the food colouring seperates out and pushes the pigment around as it dries, it’s odd!
I used a cheap spray gun from Harbor Freight to apply it.
I shook it up with red food coloring… it will separate, just like the TiO2 does. I shook the bottle a bunch and didn’t notice it separating on application to the extent I see in the photo.
Might be different food colour recipes maybe! Not sure. I just figure a safe powder pigment will be more predicable.
I have in the past used a little black tenpra paint. Turns the mixture grey and makes it more visible. I use 1 inch foam brushes to apply the mix.
I’ve seen some things dry at different rates(evaporation rates) and it will leave areas if higher concentration as material seems to pool as other areas evaporate quicker.
I was making N95 equ masks from Zn and Cu solutions on MERV-13 filters and saw this effect where sometimes the perimeters had higher concentrations as it dried first.
On the topic of TiO2 etching, would I be OK with stuff from Amazon like this:
https://www.amazon.com/dp/B076DCTWDK
or should I look for another source which has better granule size? I recall there was a discussion on granule size and I have not been keeping track of any sources people were using.
I ask because I’m helping at a local middle school with 3DP, lasers and CNC and the instructor liked the while tile I’d shown(white paint) and when I mentioned mixing elmers, water, TiO2 and soap would be kid safe. So I’m looking for a source of TiO2 to prototype on the school CO2 laser.
I use the same thing, so I’m sure it’ll be fine for the kids…
Mix it into solution, you don’t want to breath it…
I use pigments for cement with good results.
Fernando
Use 99% IPA for suspension, just mix a 75%/25% into a spray bottle and shake well. No need for stirring etc.
