What kind of glass should I have on the heated bed?

My kit came with a piece of 2.2mm fiberglass for printing on, is that what I should be using or should I be using glass like window glass?

My glass is 3mm thick and came from a picture frame. I had to shorten it by scoring one end

Normally window glass can be difficult. There are some different manufacturing processes. Most of them cannot guarantee an even surface. Borosilicate glass is often used for 3D-printing, but it is expensive. I only use this type of glass.

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Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

Ordinary float glass is adequate, but occasionally you get a piece that is bowed, so check it for flatness against the edge of a steel ruler.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

OK I will try what came with the kit but also get some glass cut at the hardware store as a backup. I see stuff listed on Amazon also but do not know what is good and it looks expensive.

I only used picture frame glass because it was $2 new and came with a free wooden frame. I don't expect it to last long

Good point. Ordinary glass is not intended to use in high temperature. If the heat is not spread evenly ordinary glass could break. Borosilicat glass can even spread the heat even.
The fiberglass from Replikeo is crap.

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Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

I use an aluminium bed instead of glass which works well. e.g. [www.ebay.co.uk]

Dave

The mk3 heatbed has an aluminium backing. In theory, you can print directly on top

[www.makershop.co.nz]

Quote
Treito
Good point. Ordinary glass is not intended to use in high temperature. If the heat is not spread evenly ordinary glass could break. Borosilicat glass can even spread the heat even.
The fiberglass from Replikeo is crap.

I've used several sheets of ordinary 3mm float glass for the last year - not had one break (yet!). I do take care to ensure that the glass is heated evenly (it sits on an aluminium heatbed) and that it doesn't get scratched (there is a sheet of thick black paper between the bed and the glass - needed to keep the ir sensor happy). The paper ensures that the glass sits on a non-scratch surface.

Like I said it depends. You can have luck or not. This is partly depending on the manufacturing process. I was not in the mood to risk this for a small amount of money especially breaking glass can be dangerous.

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Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

AFAIK all window glass is made using the float glass process these days - please correct me if anyone knows otherwise. Lots of people print on float glass. The only time I have heard of it breaking was when the user put it directly on top of a silicone heater without an aluminium heat spreader in between.

In the unlikely event that it does crack, it will probably break into a small number of large pieces, so easier to deal with than e.g. a broken wine glass.

So I see no point in paying for borosilicate, I get 3mm or 4mm glass cut to size by my local glass merchant instead. Out of about 9 pieces I have had cut, I had to throw out just one because it wasn't flat enough.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
David J
I've used several sheets of ordinary 3mm float glass for the last year - not had one break (yet!). I do take care to ensure that the glass is heated evenly (it sits on an aluminium heatbed)....

I use 4mm float glass (windows glass) on the heatbed directly without any problems, the aluminium heat spreader is not needed IMHO

Erik

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ormerod168

Quote
David J
I've used several sheets of ordinary 3mm float glass for the last year - not had one break (yet!). I do take care to ensure that the glass is heated evenly (it sits on an aluminium heatbed)....

I use 4mm float glass (windows glass) on the heatbed directly without any problems, the aluminium heat spreader is not needed IMHO

Erik

No heat spreader - the heated bed itself is aluminium.

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David J

Quote
ormerod168

Quote
David J
I've used several sheets of ordinary 3mm float glass for the last year - not had one break (yet!). I do take care to ensure that the glass is heated evenly (it sits on an aluminium heatbed)....

I use 4mm float glass (windows glass) on the heatbed directly without any problems, the aluminium heat spreader is not needed IMHO

Erik

No heat spreader - the heated bed itself is aluminium.

Not the original Heated bed. Its PCB material(no idea what it is).

It is probably FR4 some sort of fiberglass.
According to Wikipedia there are three methods of getting window glass. The most probably method is floating. But even with this method it is only most probably but not sure that you get an even surface. After having so much trouble with my Ormerod 1 I didn't want to risk this and if things would have gone wrong I would have had to buy glass at 3 or even more places to get suitable glass and for that small amount of money? Especially as I always have luck. I only can say two broken Duet boards and no clue why...

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Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.