I have an Anet A8 clone printer with a heated aluminum print bed. I'm considering purchasing a glass bed to add on top of the aluminum. When adding a glass bed on top:

  • How would I go about installing the glass onto the aluminum bed? Is the major concern here just affixing it?
  • How do you adjust for the added thickness of the bed in the printer? Is this just through a limit switch adjustment or something firmware/software related?
  • How much do you adjust your heat (if at all)? Does it take a longer warm-up time due to having to heat the glass?

1 Answer 1


The most common way to install a glass bed (assuming it's literally a piece of borosilicate glass) is with binder clips. Glass is an insulator, so you may need to adjust your bed temps by a few degrees, and it will take somewhat longer to warm up.

You shouldn't need any firmware changes, but will need to adjust whatever z homing you do. If you have a limit switch currently, you'll need to move it by the thickness of the glass. If you have an inductive probe, it should still continue to work, but your z-offset will need to be adjusted. If you have BLTouch or a piezo, nothing should need to change there.

  • $\begingroup$ you might want to adjust the firmware a tiny bit in the heating behavior region though: the expected hysteresis of a bed with a glass sheet is flatter and you should run a PID tune. $\endgroup$
    – Trish
    Apr 15, 2019 at 20:27
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    $\begingroup$ @Trish is that the case if you keep measuring temp at the bed heater? I'm surprised that you'd see noticeable performance changes with the addition of something outside of that system.. $\endgroup$
    – kolosy
    Apr 15, 2019 at 20:36
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    $\begingroup$ You can also tape the glass to the aluminium bed using kapton tape if you are concerned about hitting the binder clips. $\endgroup$
    – 0scar
    Apr 15, 2019 at 21:17
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    $\begingroup$ If you use clips and have exposed traces under your hotbed, cover the clips with insulating tape. $\endgroup$
    – Davo
    Apr 16, 2019 at 1:41
  • $\begingroup$ @kolosy by increasing the mass of the heatbed (adding glass), one increases the total thermal capacity. This means, that the heat from the bed distributes onto the larger body: Comparing pre and post mod, the temperature curve of the modded bed is expected to be flatter and taking longer to heat to the same temperature. If you have a very trigger happy Thermal-Runaway-Protection with very narrowly designed heating curve, the slower heating behavior might trip it as it is outside of the expected curve. $\endgroup$
    – Trish
    Apr 16, 2019 at 13:08

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