Clay to Glass

You can’t just drop the mic like that—we want to know how you did it!


What she said! I’m hardly believing what I’m seeing!


Nope mind bullets :stuck_out_tongue:


King of random had a nice how to

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I did several concentric circles at lowest speed:highest pew pew

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Some prefired ceramic :japanese_ogre:


Same speed / pew pew :japanese_ogre:

Too cool!

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Darn! You beat me to it! Congratulations!


Technically that is a glaze, as glass has no Aluminium in it, and clays by their nature do. I have a Stoneware teacup filled with what looks like coffee but is the remains of a piece the person who put it in did not realize that just because the clay was white it was not porcelain and ran like water at porcelain/stoneware temperatures. Glass would be much more so, which is why you can make blown glass stuff, but it would run off a pot like water while it is the Aluminum that stiffens it enough to stay on the pot but way to stiff to blow usually.


Good point :slightly_smiling_face: Is it glaze all the way through? Meaning if I melted all the material in a section would it all be glaze?

My guess is that clay goes through a transformation at about 800 degrees F to what is called metasilicate that is very porous (a lot of Mexican pottery is that way which is not a bad thing. In the desert, as the water bleeds through it and evaporates cooling the whole thing, so a vessel left out on a porch will be a lot cooler than another vessel that did not do that. However, if there are freezing temperatures the water becomes ice, expands, and the clay breaks as you often see that texture on brick buildings where the water sinks in a little and the surface pops off.

As the material heats more and more the pores shrink until they become bubbles and can even pop leaving a pitted surface, but as the heating continues it becomes a glassy surface as you see on the top.

As you get farther and farther away from the laser hit the process proceeds less and less till it is not even metasilicate and will soften and dissolve in water, that part is to me the most interesting as it could be done in a design that would have openings and so a screen like look,

A special formula would get you silicon carbide that conducts electricity with some resistance (not very much) but the longer and thinner it would be will get (i think) a solid heating element with many possibilities including much higher temperatures than nichrome. and the possibilities of a Hilbert Curve or here and where I chimed in make some awesome possibilities though kinky places are hotter than those that are not which can create problems but less at low heat than high heat.


Wow that is very interesting! I love the Hilbert curve idea!

Maybe a circular mapping to help with stress


This is amazing! I never knew!
My mother has a pottery studio, ill have to try this…


Interesting pseudo Hilbert. A regular Hilbert is open at both ends with a real start and finish and of necessity square but if each point were radiuses and there were a very even heating you could have a very fine line miles long and careful packing in porcelain kiln wash with porcelain around it, then the silicon carbide itself could bring the whole mess to porcelain temperatures with the kiln wash keeping it from shorting out as the porcelain reached the sort of temperatures that it would conduct electricity as well. (Most industrial glass furnaces do that as once the glass is molten it becomes its own heating element)

In the porcelain kilns ( I mentioned where the hobbyist buys the poured molded clays and the clay runs like water at those temperatures) the shelving for those is silicon carbide as the shelves from a hobby kiln would also be puddles.


What clay she uses could make a huge difference. The Talc clays that you usually find from poured plaster molds might work but the slightest air bubble in the clay can break the piece (as I found out the hard way). A poured mold of course would not have such bubbles.

At the opposite end in terms of standing up to laser abuse is raku clays as they are brought up to temperature and dropped into something cold (often straw) and survive where most clays would break if not shatter, so for just making clay shapes that would be my preference. Rolled to 1\8 inch and dried would be where I would start.


Thanks for the info! She does a ton of raku, so it sounds like we’re in luck!

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This is a interesting discussion. It’ll be interesting to see what else can be done along this line.

One quick observation: glass can certainly contain aluminum in the form of aluminum oxide (alumina). In fact, aluminosilicate glasses have lots of commercial applications due to low thermal expansion and high glass transition temperature (which relates to the max temperature they can be used for structural applications). Most cell phones have aluminosilicate glass screens, which are treated chemically to toughen them.

Technically speaking, the term “glass” refers to the molecular structure of the material and not to a specific chemistry. For example, there are metallic glasses, and some polymers have a glassy phase.

I agree that the vitreous coating that was produced on the clay could be considered a glaze (a glassy protective coating on a ceramic body). A flux applied to the surface of the clay before lasering might reduce the power/time required to produce the glaze.

Apologies for geeking out, but this discussion brought back memories of times spent working with glass for technical applications (fiber optics, mainly).


It’s great to see so many people on this forum with strong material science skills. We are indeed a diverse bunch!

As one who has done a bit of furnace glass most familiar with the “threads” that form from the glass dissolving the sides of the high alumnia tanks and pots it is melted that look like strings of snot and ruin a piece if they get on it, as their low coefficient of expansion (COE) will break the glass. In standard units most window, drinking, and art glass is about 80-100 range. Borosilicate (like probably our laser tubes, Pyrex, most scientific glass etc. ) is around ten I think and most porcelain around one or at least that is the ball park by my understanding, But Alumnia has another property that is good or bad depending on your need is that thickness that holds it to the sides of a pot but makes it hard to manipulate when hot compared to regular commercial soda-silicate glass.

Update - with research I see that Silicate Lava is thicker and more explosive, but it is my impression that it combines with water perhaps better than Aluminum-based lava and that I think is the cause of the diversion of properties.