Thick Glass, Thin Glass, Borosilicate Glass! What should I use?

[Dee Smith]

I'm really confused about what glass I should use for my i3v I'm assembling. I've talked to glass shops and they say borosilicate (Pyrex), anything else will shatter. Makerfarm recommends cheap $3 glass. I can find nothing definitive about the subject. Does anyone have any recommendations, opinions, etc..

I've found some borosilicate glass in the right size (214mm x 200mm x 3.3mm) for $28 but is that really worth it?

Thanks in advance.

Dee

[ciutateivissa]

I´m using a simple 4 mm float glass in my I3 and have no problems with it. The important thing is that you´ll need a heat bed which spreads the temperature equaly over the whole area. I heat my glass up to 125°C, no issues with that temperature.

[Roxy]

I´m using a simple 4 mm float glass in my I3 and have no problems with it. The important thing is that you´ll need a heat bed which spreads the temperature equaly over the whole area. I heat my glass up to 125°C, no issues with that temperature.

I'm also using cheap, thin glass. I got it at a Craft store for use in picture frames. I specifically wanted thin glass because that would help the surface be closer in temperature to what the heat bed is at. I also wanted thin glass because I used my Dremel tool with a diamond burr to drill holes in it for my spring loaded mounting screws to go through it.

So far no problems with cheap, thin, normal picture frame glass!

[old man emu]

I'm with Roxy. I used the glass out of a cheap picture frame that I bought from a $2 shop.

Shattering should not be a problem because the whole sheet is being heated at the same time, so expansion will be even over the whole sheet. Also, heat bed glass is being heated to only a little above the temperature of boiling water, so it will take it.

So go to a Cheap Shop and spend about $5 on a picture frame. Then go to an Electronics Parts store and buy a strip of LEDs (9 LEDs will do) and a simple bedlamp switch for about $10 total. That will leave you $13 to buy a 9gm servo and a micro-switch for a bed leveler.

Problem solved!

Old Man Emu

[printbus]

I had the local hardware store cut a square of 1/8-inch or 3mm window glass to match the size of the i3v heat bed, and then used my wet tile saw with diamond blade to angle the corners so they clear the bed mounting hardware. Medium sandpaper on a sanding block rounded the edges. I use MINI (not small) binder clips to hold the glass to the heat bed.

FOLLOWUP COMMENT: When I was looking around for glass, I saw some frames that had thinner glass - maybe 2mm or even thinner. I thought that was a bit thin to take out the warpage in the heat bed. I realize that the autoleveling mod minimizes the concern over how flat the glass is, but I didn't want to have to tackle that right off the bat. So, I went for the thicker window pane glass at least initially.

[gmay3]

I'm also using "I don't even know what type of glass this is" glass from the hardware store. It's about 3mm thick and was really cheap. I've had my hot end drive right down into the glass during my initial endstop setting and definitely thought it would have broken, but it didn't.

I've had no issues with sticking using 3 dollar glass and the Garnier Frutisse Extreme Hold 5 that Colin recommends and it surprisingly smells more like fruit than harsh chemicals.

The hardware store will give you the glass sharp but you can buy some emory cloth (looks like a sandpaper version of window screening) and fix it to a wood block or use a handheld radial sander. Also, you only need to take the sharpness out of the edges of the glass so you don't have to put a 1mm chamfer on it like I had imagined.

If I paid 28 dollars for a sheet of borosilicate glass, I'd feel like I've been taken advantage of.

[Roxy]

FOLLOWUP COMMENT: When I was looking around for glass, I saw some frames that had thinner glass - maybe 2mm or even thinner. I thought that was a bit thin to take out the warpage in the heat bed. I realize that the autoleveling mod minimizes the concern over how flat the glass is, but I didn't want to have to tackle that right off the bat. So, I went for the thicker window pane glass at least initially.

Just a quick clarification: With or without Auto_Bed_Leveling, you will have issues with the non-flatness of the glass. The Auto_Bed_Leveling measures the orientation of the plane (the glass) and adjusts coordinates on the fly to build normal to the plane. The amazing thing is how much distortion is in the surface of the glass. There are high spots and there are low spots. If you using the Enhanced G29 Code, you can see it for your piece of glass by doing: G29 n 5 T

If you issue the command multiple times, you will see places that are consistently higher than the area around it, and places that are lower. Also, for some reason, my glass wants to be saddle shaped. Not by much... But it is always there.

[old man emu]

There are high spots and there are low spots. for some reason, my glass wants to be saddle shaped. Not by much... But it is always there.

Err, Roxy. Did you add an extra couple of letters (gl) here?

OME

[printbus]

Of course, what the auto leveling system does is compensate for variations in the distance between the extruder and the print surface, regardless of the source. In addition to the flatness of the print surface, auto leveling will pick up variations in how "flat" the X and Y axis mechanisms are throughout their range of movement. Sagging or drooping in the center, for example, could explain a saddle effect in the result data.

[gzzmos]

As long as the glass has even pressure and isn't heated or cooled at extreme rates 2 or 3mm is fine.