I'm having trouble finding a place to buy large sheets of Borosilicate glass. I need a piece 400mm x 400mm.

So far, the best I've found is 380mm x 380mm at:

[www.amazon.com]

Can anybody recommend a reliable, cost effective place to do this purchase?

Edited 1 time(s). Last edit at 12/27/2016 11:28AM by Roxy.

If you use a heat spreader between the bed heater and the glass then you don't need borosilicate glass. Ordinary float glass from your local glazier is adequate.

---

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].

Your local glazier will likely be able to do toughened or borosilicate,which will probably be cheaper than glass + spreader (and lighter).

Buying glass local is usually cheaper, most of the cost you see online is for the shipping, even if it is free p&p.

Quote
Origamib
Your local glazier will likely be able to do toughened or borosilicate,which will probably be cheaper than glass + spreader (and lighter).

I don't advise toughened glass because the toughening process often leaves it warped.

---

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].

Can't say I've noticed any problems with toughened, but I havn't measured it.

Would a thin piece of sheet metal be the same as a 'Heat Spreader' ? If so, I might be able to give that a try.

I use 1.5mm sheet aluminium as a heat spreader on one of my smaller printers.

---

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].

I think i can chime in here as i have been experimenting recently, bear in mind my bed size is 420 x 420mm so slightly bigger than what you need. Here is what i have tested recently.

- 4mm Toughened Glass - Excellent value for money and never seems to be un-even enough to cause problems with first layers, does't shatter with heating cycles but will bow and mould to the shape of an un-even bed, so make sure your "Bed Base" is perfectly true (Mine is CNC milled). One side of the glass is sandblasted, and i am still testing getting prints to stick to this properly, it has to thoroughly cleaned before trying to print on as powder is left in the texture from the manufacturing process, but it leaves a nice texture on the bottom of the parts.

- 2mm Aluminium Tooling Plate - The Aluminium has 1.5mm Phenolic Sheet (Whale Tufnol) bonded to one face, and 2mm Polycarbonate (Lexan) bonded to other, we have Heated Veneer press at work so i bonded them together in that (20 tons of pressure and heated to 80c to cure), after that i trimmed the sheet to size on the cnc, it was near enough perfectly flat. The phenolic was to be used to print Nylon (With a moderate bed heat) onto and the Polycarbonate was to be used to Print PLA & PETG onto (with very low bed heat).

The issue was with the "Multi Purpose" Surface was that it bowed when it was heated, i had another tooling plate that i heated on its own and it suffered the same, this is probably because the print surface on my bed is not held down, the heater is a black silicone one which friction holds the glass in place. Therefore if you wanted to glue the tooling plate to your heatbed it would probably work much better.

I've never seen 2mm thick tooling plate anywhere. Did you mill it down from 1/4"?

---

Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

No i bought it online, it was advertised as milled then brushed finish, it was true when it arrived but not after heating. The website was Metals4U, it was the only placed that offered it so thin, others the minimum was 5mm.

Thanks

Surely 2mm tooling plate would be too flexible to define a flat surface? It seems to me that there are two choices:

1. Use thick tooling plate to define the bed surface, that is rigid enough to remain flat. Either don't use glass on top of it, or use glass that is equally flat.

2. Use thick flat glass (at least 4mm for a 400x400mm bed) to define the bed surface, and use a heat spreader that is thin enough that it will bend to conform to the glass.

I have one printer using each of these systems.

Btw be careful of using toughened glass. If you get a flat piece, that's great; but the toughening process often warps the glass.

---

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].

I'm using 5mm tooling plate on a 330mm circular bed, and printbite bonded to the top of it. It's the flattest bed I've ever used.

I cannot see what advantage any glass brings if you have a sheet of aluminium flat enough, thick enough, cast and machined. Glass is potentially expensive, fragile, not as flat as you expect it to be and an insulator, not much to recommend it really.

Edited 1 time(s). Last edit at 01/07/2017 04:12AM by DjDemonD.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Quote
DjDemonD
I cannot see what advantage any glass brings if you have a sheet of aluminium flat enough, thick enough, cast and machined. Glass is potentially expensive, fragile, not as flat as you expect it to be and an insulator, not much to recommend it really.

Float glass is very cheap. The advantages of a glass bed are that you can remove it easily and have several of them. There are a few reasons why you might want to do this:

- So that you can start a new print before the bed has cooled down after finishing the last one;

- So that you can put it in the fridge or freezer if the print sticks too well to it;

- So that you can easily try out different bed surfaces without having to glue and un-glue them from the aluminium each time.

So I print on glass. However, if I had a print bed larger than about 320mm square or 320mm diameter, then it would be more difficult to handle and wouldn't fit it the fridge, negating some of its advantages. In that case I would probably use PEI glued directly to aluminium.

It's true that glass is a relatively poor conductor of heat, so I set the bed temperature about 5C higher than I want on top of the glass when printing PLA, and I used 10C higher when printing ABS.

---

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].

The go-3d print website has some 400x400mm borosilicate glass along with plenty of other sizes