Chipping Ultimaker glass beds

I’ve just managed to chip my 3rd Ultimaker glass bed - 1x on the 2+ Connect and 2x of the S5 beds. These things aren’t cheap so I’m wondering if I’m doing something wrong.

The problem is when the print is complete it tends to take a small shard of the glass plate with it, embedding the glass in the base of my print. You can simply invert the glass plate or print around the shard, I know many people have this problem but it’s starting to annoy me.

I think I’ve only ever done this with ABS or PC - and only when using Magigoo. I’ve stopped using Magigoo in favour of a good brim with a UHU stick on ABS, but still use it for PC (using the PC variant of Magigoo).

I also suspect half my problem is that it’s getting pretty cold in Melbourne these days, so I’m worried that printing overnight is leading to the print bed cooling down too quickly?



Hi Jordon,

Sorry to hear this has happened so many times to you! I spoke to one of our staff who has used these printers extensively, and he said he had similar problems in the cold. His solution was to use adhesion sheets to prevent damage to the bed:



Thanks James! Good to know my hunch on the cold is a factor! I’ll grab some adhesion sheets.


Hi Jordon154141,

I do a good amount of 3d printing. I have the same issues. I think it comes with the territory.
Printing on glass gives you a superior flat finish that’s hard to beat.
I print predominantly in ABS plastic. I cut my own glass, for this reason.
One can use anything except for tempered glass. That will just shatter.
If you’re savy, people put out glass all the time for curbside recycling. Or you could go to your local glass shop and get their offcuts for a small amount. Thick or thin is no real matter.
It’s cheap and easy to do after a few goes.

If you’re interested you can do a home heat treatment by placing the glass in your domestic oven for a short period of time. Then let it cool naturally. Though it’s not mandatory. It just gives it surface and edge compression. If you’re interested just Google something like “DIY heat treatment of glass at home”.
I tried it out a few times. I did it in the kitchen oven. From memory it’s something like 300c for 10 to 20 minutes, one treatment is enough. I started from a cold oven with the glass on a metal baking tray. Then let it cool naturally. Do it when the Missus goes out to the shops and nobody will be the wiser. Remember to do all your cutting before heat treatment.
I will stress this statement…
The number 1 rule is don’t cut your glass so that any part of the glass extends past the heated bed. That is, no glass is to be left unheated by the 3d printer’s heat bed. No exceptions.
Doing so will result in cracked glass bed guaranteed 100% every time.

Make a slurry of ABS juice to use as your bed adhesive. This way you can control the amount of adhesion between the glass and the print.

I personally try to let the print come away from the bed with gentle separation. Leave the print overnight on the glass. Sometimes heating and cooling the bed with the print attached. Then let it cool to room temperature. It’s a slow process I know.

Use an enclosure always for your 3d printer. If you haven’t got one make a tent up from a suitably large bag.

I hope this helps you or someone else who has issues.

Good luck.


Here’s a good article for safely removing 3d prints from print beds…

I hope that this helps…

Eddie :grin:


Placing prints into a freezer (while on the glass) helps remove them without any upward force. In a cold environment, the plastic will contract much more than the glass and dislodge itself.

That’s my go-to method for stubborn prints - luckily our workplace freezer is often empty.


I had the same issue printing PETG on glass. I have solved the issue by running the following script at the end of each print. The idea is to slow the cooling of the glass so it cools evenly. The printed model acts as insulation creating a hot spot under it causing heat stress in the glass. This causes the glass to break at that point. This gcode slows the cooling of the glass by stepping the bed temp down in 5 degree steps. I have not had any glass break since i have been using this. The times and steps can be easily changed to suit your climate.

G91 ;Relative positioning
G1 E-5 Z0.2 F5000 ;Retract and raise Z
G1 X5 Y5 F3000 ;Wipe out
G1 Z20 F2400 ;Raise Z more
G90 ;Absolute positioning
G1 X0 Y{machine_depth} ;Present print
M106 S0 ;Turn-off fan
M104 S0 ;Turn-off hotend
M84 X Y E ;Disable all steppers but Z
M140 S75
G4 S180
M140 S70
G4 S180
M140 S65
G4 S180
M140 S60
G4 S180
M140 S55
G4 S180
M140 S50
G4 S180
M140 S45
G4 S180
M140 S40
G4 S180
M140 S0 ;Turn-off bed

Hope this helps others as it has myself. I am interested to hear if it works for others.