The glaze probably melts near 1000C and we know there is a phase shift much lower than that which causes spalling. Visible red heat is about half that so it would be very bright for at least a while after the laser passed in nearly every case and burn your hand to come near. In any case in an oxygen environment any carbon would be long gone by then.
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Yeah I don’t think it is the carbon that is causing the color change, imo it is the talc or some other element in the paint being fused with the glaze in the tile.
In my score line defocused test you can see black glass in the track left by the laser showing it is being melted.
But either way like i said before more than one thing probably going on. Will need to run more tests but I was going to do that anyway. Have you done anymore tests beyond your glue and turmeric ones?
When talc is heated it decomposes into 2 main minerals.
“At 800 to 8400 C the talc decomposed to enstatite, amorphous silica, and water’ vapor. The enstatite gradually changed to clinoenstatite around 1,200° C, and the amorphous silica changed to cristobalite around 1,300° C, giving clinoen- statite and cristobalite as final products.”
https://nvlpubs.nist.gov/nistpubs/jres/15/jresv15n5p551_A1b.pdf
When I tried paint that contained no talc there was no visible effect on the tile. It looked like any normal tile engrave. But anyway agree to disagree, that is my best guess so far with the tests i’ve ran. I’m going to buy some talc and find a way to put it on the tile without the air assist fan blowing it all away lol.
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Mix it with a solvent and brush it on?
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I was thinking that, or possibly lay down a layer of clear coat sprinkle the powder on then top coat it with clear afterwards.
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A real tale would be a tiny bit of cobalt carbonate, especially with a bit of borax… cobalt at 1/1000 is almost black while 1/50,000 is detectably blue, while boric acid forms a glass with silica even if nothing else is added and is frequently used just to form a shiny surface sealing a wide range of clay bodies.
Even if the tile glaze did not melt, the borosilicate might be hot enough to form a bond. No doubt if measured by the light of the moment, the air at the point of contact is easily 5k degrees C but the key is measuring the glaze even a quarter inch behind. Aluminium melts at under 500C so painting some Aluminium foil and hitting it could be very revealing.
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Painted aluminum foil test. it was a score test speed 250 power starting at 10 on the left and going up by 10.
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Was there any melting? 500 C would do it.
Yeah you bet, it started poking holes in the foil around 20-30 pews and i shut it off at 90% as it was just blasting it away. I wonder what would happen if you did this on bare aluminum tags? would you be able to etch it? I worry about reflections, but if it can be done at say 30-40% power it might be ok to test.
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That was why I was thinking about the paint, that it would absorb reflections.
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If you can find 20 mule team borax (not boraxo that is soap) or boric acid roach powder that will make a glass if you have it in a binder. Wood glue might make a black(after burned) binder, or gum tragacanth that I used before but had to add a serious oxidizer to keep it from being black.
That is awesome! So much depth!
Is it meant to be a “real” Popeye?
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No I would not. About the only thing I leave running if I leave the room is the lights… and maybe the tv… and sometimes the shower… well the coffee maker runs… 
I’m not sure. It’s a pretty cool piece of art for sure.
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Wow, that engraved really well! I need to find some time and paint to try this! You guys seem to be getting some really amazing results!
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Our local Walmart carries it.
It is commonly used in laundry. Just make sure you get the borate and not as a friend did, the soap.
One is good to turn into a glass that would remove oxides from molten metal while the other is just a burning mess, that my friend could not understand why it kept messing up his gold castings.
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That turned out mostly ok. I don’t see any banding on mine. I used a medium layer of paint… Then after a couple hours I put a lighter coat on. And then I waited about 24 hours before I pew-pewed it at 225 speed / 25 power / 430 lpi. Roughly 2 hours to finish.
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These are all awesome. I tried one a couple of days ago but it didn’t turn out…I can see now my settings were way off. Can’t wait to try it again.
Thanks!
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My wife uses it in making a laundry detergent.
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