Is my heated bed glass too thick?

Will be ok if I use glass 0.25 in thick? my only concern is that gonna take too long to heat and probably will be consuming too much power.

It's more than 6mm when I convert this. The ideal thickness for me was 3mm, but I moved on to using Kapton on aluminium plate.

It might act as a heatsink, but I'm not sure if you should worry. Why not just try it? It would be a good idea to isolate the bottom side of the printbed anyway.

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http://www.marinusdebeer.nl/

I can't see a reason to use thicker than 3mm. Glass is used as a thermal insulator so your bed will have to be much hotter for 6mm glass.

I am using 6mm glass on a standard 12v reprap bed heater. It works fine. One advantage is that it is more robust compared with 3mm glass. It is a nice firm base for printing on. I bought float glass which is dead flat. Slight trade off is that it takes slightly longer to heat up due to the greater mass.

Also glass is not a thermal insulator. It is an electrical insulator. It actually conducts heat very well.

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dave3d
Also glass is not a thermal insulator. It is an electrical insulator. It actually conducts heat very well.

"Very well" is very relative. Glass has a thermal conductivity of 1.05 W/(m.K). That's quite a bit more thermally conductive than fiber glass insulation at .05 W/(m.K), but a long ways away from aluminum at 200+ W/(m.K). Glass will take longer to heat but will also retain that heat longer than a more conductive material so will help temper any temperature swings and hot/cold spots once it reaches temperature.