(NOOB): Size of glass for 10" i3v?

[dacb]

I did use some sand paper to clean up the edges, forgot about that.

[DjWang]

I went to Home Depot and bought a 6 pack of 12'x12' mirrors for $12.00 and a glass cutting wheel. Then, like dacb; I scored and snapped them down to 10"x10" and trimmed the corners by scoring and snapping with pliers. Then sanded down the snapped edges with 220 sandpaper.

I noticed with the mirrors that my actual bed temperature (measured with Fluke laser thermometer) is 10 degrees C less than what I ask for. Set for 110C but measure 100C. Not sure if this is the same for glass but thought I should note it.

[jtice]

My Ace Hardware glass ranges from 7C to 10C cooler than what my Prusa is set for.

[gmay3]

I'm not totally sure, but I think it might make sense that all heatbeds with glass on top will measure in similar way.

I think the thermistor being sandwiched between kapton tape, the bed, and some sort of insulating material creates a very small air gap that holds its heat in much better than the surface of the bed which is open to the environment. I wouldn't be surprised if the thermistor is measuring the correct temp for its location underneath even though this isn't a very exact measurement for the surface of the glass.