Aluminum Heated bed - with or without Borosilicate Glass Plate?

So, I have a 3mm aluminum heated bed (24v) and it came with a 3mm borosilicate glass plate. I also got a PEI sheet. My question is - what combination of the 3 should I be using? My intention was to use all 3 (PEI on glass) but I want opinions from you guys as to your experiences. I also want to know if High Temp tape can be used to hold down the glass plate until I can print out some clips? Thanks once again!!

I just use binder clips.

I use the heated plate and the glass. The binder clips hold the glass directly to the plate.

I have been scolded for applying PEI directly to the aluminum. That’s what I do though. I have a BLTouch sensor too, so the glass might help of you’re doing the manual bed leveling.

DUI swears by using glass, and if he has trouble getting a print off, he puts the whole thing under a stream of cold water, or was it the freezer?

Thanks for the feedback. I figure since I have it, I might as well use the glass. Should I put the PEI on the glass or just go with the glass by itself?

I like the binder clip idea - simple and easy!

I might have to look into a BLTouch - it seems like it makes life easier…

The glass by itself won’t stick. You can use blue painter’s tape, glue sticks that start out purple but dry clear, aquanet hair spray, or PEI. The PEI will last a really long time, but if you’re new to printing, you might keep it for a fun upgrade after a bit of trial and error. I think it was giving Kelly D some headaches not knowing what the problem was with adhesion.

Have I given you the caution yet that I will gladly tell you how I did something, but I’m not making the recommendation to follow me? I look at this printer as a research bed, and I enjoy tinkering with it. I don’t know if any of the things are better, or worth the effort or cost.

That said, I really like the BL touch, but I think you have to do your dues leveling with the screws before you’ll appreciate it fully. There’s a lot more configuration that goes into it, or any bed leveling, but once it’s set up, it can compensate for some goofy beds.

Ryan doesn’t like them, and he has 6 printers printing all day long.

Kelly D had good luck just buying a BL Touch and putting it next to the printer, as a threat.

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Jeffe - thanks for the pointers. I’m just looking to gather thoughts and then start playing on my own. I am probably gonna start with the glass plate and tape since that seems like the “easiest” solution to start off with. Once I figure out how to get the printer to actually do something (instead of just sitting next to me taking up space, lol) then I will start exploring other options.

As for the BLTouch just sitting next to the machine - that’s what the Z Touch plate I got for my LR2 is doing right now. lol. I bought the damn thing but haven’t had time to set it up yet. Too many projects, too little time - if only that pesky “work” didn’t get in the way!!

I concur with Heffe, learn how to do decent prints without the PEI. Once you have tweaking down, put the PEI on and go production. Getting the PEI off again is a real pain so it’s best to only put it on once you are sure you are ready, but it makes things sooo very nice. :slight_smile:

The new thing seems to be the magnetics. You have a bottom layer adhered to the bed and a top layer that pops off to allow easy print removal. If you’re doing production you just have several top layers that you swap between jobs. I wonder if they do a better job than glass and aluminum with the inductive sensors? The BL Touch requires a servo output, so another pair of wires to deal with…

I love Aqua Net and glass. But, I’ve never tried PEI. I’d be happy to try it if someone sent me a free sample, but Aqua Net and glass works so well I don’t have much incentive to buy PEI.

I don’t like binder clips to hold the glass. Reason being, the aluminum heated beds are notorious for warping under heat and not being flat. You may not realize it, but glass will flex. Binder clips holding the glass to the warped aluminum will make the glass flex and also no longer be flat. Plus, they get in the way of the nozzle. I use 0.5mm thick thermal pads under the corners. They let the glass “float” over the aluminum remaining flat while the aluminum warps and twists under from the temperature changes. There’s no fiddling with the clips to take the glass off or put it on. Simply pick the glass up and set it back down and done. And it keeps 100% of the bed clear for the nozzle. It’s definitely not wrong to use clips. Do what works best for you. It’s just not my preference.

Also, you don’t need borosilicate glass. It will still break under impact just like pane glass. But, borosilicate resists shattering under thermal shock (extreme and uneven change in heat) by being more flexible than pane glass. However, the temps we deal with on a 3D printer heated bed are well within the tolerances of pane glass. Even printing ABS, you’d have to double the typical print bed temperature to even think about needing borosilicate. Plus, the temperature change on a heated bed is slow and evenly dispersed. Even going directly from the printer to the freezer is not enough thermal shock to need borosilicate. Regular pane glass is just fine for a 3D printer. It’s easier to source and it’s cheap. The local hardware store can typically custom cut a piece for about $3.

Use the pei on a spring steel plate. Makes print removal so easy and the pei sheet will last longer.

Yes, the BL threat has worked pretty good for quite a while now. Hahaha

So my bed got a little bulge in it near the thermistor (in the middle). I accidentally left the printer heated up all night long and swear that’s what deformed the bed. Up until then I had been using the bed with the PEI sheet stuck down to it and was having good success. After the goof up it was a nightmare. I ended up doing two things. 1) I binder clipped a piece of glass from a dollar store picture frame right over top of the PEI sheet. And 2) If I have a print that is going to involve that middle region of my bed I will tell slicer my bed is only 150mm deep (for example) which shifts the print forward of the trouble zone.

I do not use hairspray, do not use tape…nothing. I have printed mostly PLA but some ABS as well and have had no major adhesion troubles. I do use brims or rafts where required if the print doesn’t have much bed contact area. I clean the glass frequently with 95% iso though. I feel like that makes a difference. And don’t use the 75%…nothing but trouble for me with anything but the pure iso.

Same for me. No hair spray, tape, or glue. My print bed is 300x300 so i actually use a 12”x12” mirror. Using the back side to print on gives a less glossy surface but prints adhere just as well on either side.

I use binder clips with mine and I actually use an SN04-N inductive sensor with bi-linear leveling and it works great. I rounded the face of the sensor by sanding it to allow mainly the center of the sensor to be nearer to the bed. It senses the heated bed through the glass and triggers about 1mm above the surface of the glass.

The first 2-3 inches of plastic out of the nozzle might not stick right away and can wreck the print, so i always watch the print start. A quick snatch with tweezers to remove anything that didn’t stick while it’s still just printing the priming skirt is all it takes to fix it.

Prints release themselves from the glass usually within 5 minutes after the print stops.

Note: Being a mirror, objects are closer than they appear and the reflection can really mess with you, especially while trying to dial things in. I’d recommend using the back side until you’ve dialed in the z probe offset.