Installing a glass bed is one of the most common upgrades on any 3D Printer, there is simply no better build surface out there. New owners find themselves with more questions than answers though, encountering a wide range of opinions as to what will work best. Suggestions include anything from using picture frame glass and glue sticks, to the more expensive borosilicate glass and hairspray.
The truth is, there is no one method that will be the best choice for everyone. When I switched to a glass bed from the standard Build Tak surface, I experimented with every option available. After nearly pulling out my hair in frustration, I found a plastic sheet called PEI to work unbelievably well. I will cover the most popular options for both glass and adhesives, then show you how to install the bed with a PEI surface.
Borosilicate Glass Plate - $0.00 PEI Sheet w/ 3M Adhesive - $16.95 Binder Clips - $8.99
Using a glass bed offers several advantages over the traditional tack surfaces found on many 3D printers. Parts will have a smooth, glossy finish on the bottom, where the printed layer lines will be nearly invisible. The glass bed can also be removed from the 3D printer as needed, a convenience for prints that may prove difficult to remove. Placing it into the freezer for a few minutes will make the plastic contract and pop off with ease. A flat piece of glass will also cover any deviations in the aluminum bed, which can warp and become deformed over time.
Choosing the Glass:
Borosilicate glass is the strongest and most durable option available. It has superior thermal shock resistance and lower thermal expansion, where it is created by replacing one of the chemicals in regular glass with boric oxide. These are fantastic qualities for 3D printing applications, where the glass will often be subjected to rapid changes in temperature on a heated bed.
Tempered glass by comparison is just normal window glass that has been post treated with chemicals. While this does improve the strength, post processing glass does not achieve the same degree of structural integrity, making it a decent albeit lesser alternative to Borosilicate glass.
Video: Borosilicate vs Pyrex Glass
As a third option, many owners opt to just use standard window glass, cut to size by a local shop. Depending on cost and availability, this may worth consideration for those on a budget. Window glass should be used with precautions though, where it can have sharp edges or shatter during temperature fluctuations.
Choosing the Adhesive:
Printing directly on to a glass bed alone will not be enough to hold prints in place, some type of adhesive component is strongly recommended. The most common choices include…
- Blue Painters Tape
- Glue Sticks
- Aquanet Hairspray
- PEI Sheet
The problem with most of these choices is that they are temporary, requiring you to reapply them on a regular basis. As the best option, PEI will provide exceptional adhesion and require almost no additional upkeep over time. I have yet to encounter a single problem with prints sticking to the bed since it was added months ago, still going strong after being used hundreds of times. When the surface quality does eventually begin to deteriorate, you can simply use an abrasive material such as sandpaper or steel wool to restore it.
We will start by attaching the PEI sheet to the glass plate using the included double sided 3M adhesive. Peel off one side of the backing sheet, exposing the adhesive layer underneath. Keeping the adhesive sheet taut to minimize air bubbles, lay your piece of glass on top.
Using a textbook, rolling pin or anything else you may have available, apply even pressure to the glass plate and press it firmly into the adhesive. When finished, we will go ahead and flip it over, where the remaining covered side of the adhesive is facing upwards. Go ahead and carefully pull off the second paper backing sheet, leaving the glass and the 3M adhesive sheet exposed.
Warning: If your 3M adhesive sheet is larger than the glass plate, place a piece of cardboard underneath to catch any excess. It is extremely difficult to remove once stuck!
The PEI sheet will have a protective blue plastic covering both sides, where you can go ahead and remove one of these now. With that side facing the glass, align the bottom of the PEI with the bottom of the glass plate. Bending the PEI at a slight angle, start by laying the sheet in small sections and pressing out any air bubbles before moving forward.
I used a paint scraper with several layers of blue painters tape to dull the sharp edges. You can also just use your fingers, a credit card or any other tool as long as it will not damage the PEI surface when doing so. The goal is to completely push out the air bubbles that formed in the adhesive before laying the next section.
After the PEI sheet has been laid on the glass and all air bubbles are removed, we need to place even pressure on top to make sure it sets. I centered a stack of heavy books and boxes of filament to firmly compress the PEI, adhesive and glass plate together. I would recommend leaving this for no less than 30 minutes, where 2-4 hours would be optimal.
From here, all that remains is removing any excess material. Flip the stack to the other side with the glass plate sitting on top. Using a box cutter, treat the glass as a guide and cut down each side, pressing firmly to cut through the plastic PEI sheet. You may need to make several passes with moderate pressure, where I recommend doing this on a disposable surface such as cardboard.
Now there are several different methods of placing the glass bed on the 3D printer. Some guides recommend using thermal adhesive pads, cut into squares and placed in each corner of the center of the glass. I personally found this method overly complicated and it seemed to delay the actual heating of the glass.
As a better solution, I recommend simply using binder clips to hold it directly to the metal, placing them around the perimeter as needed. Just take care not to damage the heating element on the bottom of the aluminum plate.
21 thoughts on “Guide: How to Install a Glass Bed”
Did you not have to adjust the Z-axis end stop sensor? Mine won’t fit under the home position of the nozzle as it sits.
I actually adjusted mine several times, then came to the realization it was not needed and went back to the original position. Tighten your bed down in the corners as far as it will go and see if it fits under the nozzle. If that is not the case, you may need to raise your Z-axis end stop 1 or 2 notches to give sufficient space.
I’m planning on installing a glass bed Xmas morning. I got silicone Gino pad to use underneath. Have you tried that rather than binder clips?
I actually started out with the silicone pads and didn’t like using them. It looked great to start but they didn’t hold my glass in place very well. I also ran into issues when taking the glass off, they would stick to it and peel up, making it a bit of nuisance when they continued to stretch out.
I ultimately switched to binder clips and haven’t looked back, I use them for all 4 of my printers that have glass plates. The ones that clip on and flip back work great, it keeps them out of the way of the hotend and they stay put until I am ready to take it off.
When I use binder clips – they small roll in the clip that holds the flip-back metal clips hit the fan mounted on the front of the extruder. Did you need to reduce the size of the printable area so yours do not hit?
This is probably dependent on your hotend, what fan you are using, etc. On my Maker Select, my Dii Cooler clears the clips without any problems. My CR-10 and D-Bot however hit them if it gets too close, so I just account for that when positioning the models in the slicer.
I would say don’t be too concerned about moving the clips as needed though. I sometimes do one in the middle on each side, other times I will put one per corner (front right, right top, back left and, left bottom). I don’t have to change them frequently but if I am printing a large design, sometimes I have to think about the best way to do it.
That’s really interesting that your dii cooler doesn’t hit the clips. I have a Maker Plus and my Dii Cooler keeps snapping the clips off. I actually just ended up giving up on the glass bed for a bit until I can figure out a better adhesive solution. I wonder if there’s something I can do to raise the dii cooler up a bit..
The clips I am using are very low profile, and the cooler does sometimes lift just a bit when passing over them, but I haven’t had any notable issues. Check out Thingiverse though, people have made various designs that lock the glass in place at the corners. If it is causing issues though, you may actually be better off just using the thermal pads.
I’m having trouble getting my prints to stick. The glass bed + PEI sheet worked great for a few prints but now I am having lots of issues.
What bed temperature are you using when printing with the glass bed?
There are a few factors to consider but the glass + PEI should definitely be working almost perfect. As for temperatures, this depends on material, glass thickness, etc. For PLA, I use between 60-70C. My Maker Select has thinner glass and 60C works fine, but the CR-10 glass is a bit thicker, where I have found 70C works better on that machine. When printing hotter materials like PETG, I bump those temperatures up to around 85C.
Have you checked your bed to make sure it is level? This is often where I run into some problems with adhesion, but it is resolved as soon as I re-level the bed. I also wipe down the PEI with 91% isopropyl alcohol every few prints, just to keep the surface clean of any debris.
Has anyone tried using Kapton tape on their glass surface? I just started using it with ABS and find I still need to use an ABS/acetone slurry to aid adhesion. More experimentation is probably required. Anyway, I just got a roll of PETG and will be trying it on this surface.
Kapton tape as a print surface was much more prevalent a few years ago, but we have a better selection of options to choose from these days. It will work but adhesion can be problematic, not to mention the tape is much less durable than other choices. I prefer PEI above anything else, but would probably choose painter’s tape or glue before I used Kapton tape.
I haven’t tried Kapton, but I have used a simple glue stick since installing my glass bed on my Maker Select V2 about 2 years ago, and I have loved it. You just heat the bed, put a very light layer on the bed, and print. Afterwards, a lightly damp cloth will remove the glue with ease. I haven’t found a reason to try anything else since starting with the glue sticks.
I removed the original Maker Select 3D Printer surface, (PEI?). Is that what you did?
If so what did you use to remove the adhesive from the aluminum bed?
For this particular 3D Printer used in the guide, I did remove the original BuildTak surface before adding the glass/PEI. Tried a few different products but ultimately found Goof Off to work the best, although it still took almost an hour to finish the job.
A lot of people recommend removing the BuildTak when adding glass, which is why I chose to do so my first time. Since then, I have added the glass/PEI combo to dozens of other 3D Printers and normally leave the BuildTak surface on it. It saves time, looks better and doesn’t seem to affect the heat up times nearly as much as others have indicated.
I have added the borosilicate glass plate with the pei sheet, but i cannot get a single print to stick. Im getting very frustrated and hope i didnt just ruin my original plate. what can I do to solve this issue. I have done a three point conversion for my bed plate and have tried levelling it 20 times.
Adhesion should definitely not be a problem with PEI. In fact, the only real complaint anyone seems to have is that certain materials like PETG can stick too well. Just to ask, did you buy it from Gizmo Dorks or another seller? There is a lot of knock off PEI out there, so I would just like to make sure you got the right product.
Otherwise, what type of filament are you using? If it’s not sticking, my first guess would be that the nozzle is either too far from the bed, or the bed temperature isn’t hot enough. For glass, you may want to either run temps a bit hotter (such as 70C instead of 60C for PLA) or just give it an extra minute or two for the glass to heat up. Remember that the thermistor is reading the bed temp and while heat does rise, the glass may take a little longer to reach the same temperature.
When you use PEI, why would you still need a glass plate? Can’t you just glue it on top of the aluminum printer bed?
You can absolutely stick it to the aluminum bed if preferred. In many cases however, the build plate/heated bed is not perfectly flat and we use a glass plate to cover defects. Glass plates are traditionally used to create a flat, removable print surface, and attaching the PEI to it instead makes sense.
The bed on my printer has a rather substantial dip in the middle (when viewed from front to back) around 1mm down in the middle. Would a glass top still conduct the enough heat given the size of the gap, or is it best to source a new bed?
I have though of possibly padding the gap out with painters tape so the glass could still be in contact with something.
Replacing the warped heated bed with a flat build plate is the best choice, that’s addressing the core issue. Options like glass and padding will be more of a band-aid solution to mask the problem.
However, purchasing a quality heated bed is also the more expensive route. A glass plate on top will conduct heat well as long as it’s making sufficient contact with the hot surface. If your bed is significantly concaved in the middle though, that may cause it to lag behind the temperature displayed on screen. You may end up relying more on the heat rising as opposed to direct contact. Having been down that road before, I would preheat the bed a bit warmer (70C instead of 60C for example) and let it sit for 5-10 minutes before starting the print. Not ideal but it worked well enough.
It’s worth mentioning, aluminum is pretty malleable. If you’re comfortable trying it, you can lay the build plate on your knee and press down on the sides. Do this in small increments and then check, it’s easy to overshoot the mark and bend it too much the opposite way. To check flatness off the 3D Printer, lay it face down on a flat surface (stone countertops work well) and press the corners, edges and center to see if there is any flex or teetering.