Durst L 1000 glass for negative carrier

I have on piece of glass for the Otoneg 2 negative carrier. It's an Otoglas AN anti-newton glass, and fits in the top of the negative carrier. As near as I can figure out, the bottom glass is a special glass from Durst, which I'm unable to find. Can I use regular glass if I can find something the right thickness (which may be an unlikely find), or is there such a thing as optical glass sheets? It's 6 inches wide (15 cm) by 4 and 15/16ths (12.5 cm) wide and is beveled on all 4 sides. The sheet I have is close to 2 mm thick.

I checked my original Durst L1840 glass (Reglas) and it is 2.80mm thick. I used to have an older 8x10 Durst neg carrier and it used slightly smaller Graglas. I still have a piece of Graglas and it also measures 2.80mm.

I also checked the original glass in the Durst L1200, and it measures 3.00mm.

A few years ago I broke the glass in the L1200, and briefly substituted common picture framing glass. I’m not sure of the thickness, but it worked just fine. But eventually I had Focal Point in Florida (Mike Sparks at 386-860-3918) make me a replacement.

So my opinion is that any optically clear glass would work, so long as it is close to the right thickness. Measure your top piece, and try and get a bottom piece of the same thickness.

Thanks for the help. I'll borrow a micrometer to check the thickness of the top piece, then call Mike Sparks.