I will make another window, using the lessons learned from making the first one. Hopefully this one will be good enough to incorporate into my first blinker device.

This time I will employ a new technique for creating neater glass circles, and rinse the glass with deionised water after the acid bath. I will also attempt to smooth the kiln/bat wash to get a better bottom surface.

I used a circle cutting technique shown in this video. It worked very well and produced quite neat edges on the circles.

Beautiful!

Wow!

As before, I soaked the glass in HCL overnight to remove surface impurities. Afterwards I washed them with tap water, then with deionised water.

Soaking in deionised water.

I then put them in the kiln at 70°C to dry. Afterwards I found the glass quite dirty. There were mineral deposits and general filth visible on them. This was very disappointing. I suspect the low-grade deionised water I am working with is not actually very pure.

Not recommended.

I manually cleaned each window by hand to remove as much contamination as possible. I started with paper towel, but that left paper fibres behind on the surface. I switched to chux, but that had a similar issue. I settled on using zeiss individual lens wipes. Even these got a bit ragged when being dragged over the edge of the glass. I had to go through quite a few of them to get the glass clean-ish.

Re-firing window 1, firing window 2 for the first time.

A slower initial ramp than last time. Same peak temperature.