glue to release

Seems counter intuitive to put glue down on the PEI surface to get the print to release better after it is finished. Can someone explain the chemistry going on there? Thanks.

Release agent

Don’t get hung up on “glue”. PVA is a common release compound and holds up to the heat. It comes in liquid form to cover larger molds, but a glue stick is more accessible and easier to handle for a print bed. Also water soluble for “easy” clean up.

Ok. The PEI surface on my Taz has a tear in it from removing a print. Is there a way to repair it? Will this cause issues with subsequent prints?

Not sure how that applies to “glue to release”…

No way to repair the tear… could try some CA glue, but most likely needs to be replaced.

If the tear is in the middle of the bed and you print on top of it, then it will affect your print. It’ll leave a mark.

If the tear is on the edges, then try to print around it. Most likely though it will contribute to the PEI bubbling.

Do you have more guidance on using the glue? Do you put it on only when the plate is cold? Can you put it on when the plate is hot? Do you need to wait for it to dry before you do a print? Do you only put enough on for the size of the print? Or do you coat the entire plate? Do you wash it off after? Do you apply more every time you print? Or how do you tell when you need to reapply?

  • I’ve only used PVA Glue (Elmer’s purple glue stick) with n-Vent. That said -
  • I’ve applied glue on it when the printer was off and the bed cold, and another time when I heated the bed to about 45 deg C. I found no noticeable difference in impacting my prints. It’s easier to apply with the bed warm, though. It takes a few minutes for my Taz 6 to go through it’s auto clean and auto level process anyway before it prints, so by default there I do have a few minutes for the glue to dry before I print.
  • I’ve only put enough for the size of the print since it’s only needed for the print’s surface area.
  • Yes, I wash the glue off in-between prints with a wet paper towel.
  • I reapply between prints that need it. I don’t put a very thick layer, nor do I put a very thin layer. I just apply glue on the bed as I would if I was applying it on paper.

Thanks Platypus,

Very helpful.

I use a regular glue stick from walmart nothing fancy, i use it more on my custom printers rather than the taz 5 that i have however for larger prints and very solid prints i will use the glue on my taz 5 as sometimes the prints start lifting on the corners. So i use the glue mainly on my custom printers as the way the heatbeds are set up they dont stick as good as the taz 5 with that being said i put the glue on hot or cold doesnt seem to matter. I will use the same glue a few times. in between prints you can just lightly wet the glue with water and use it multiple times after you do some prints you will start learning how often you will need to completely clean it off. I will say when using the glue on the taz 5 it can sometimes be a pain in the butt getting the print off so be careful or you could break your prints.

Yes. I have a Taz 6. Prints lifted off easily when it was new. But after 20 prints or so, it became increasingly hard to remove them, until the prints started breaking during lifting, and finally the PEI tore. The glue seems to help, but still seems to be a bit of an art.

In lifting the prints, I kind of ram the provided “Precision Knife” against the edge and twist to try to lift it up. I try from multiple sides, multiple times, until eventually it comes off. Not a great or predictable process, and does mar the print along the edges. Anyone have a better way to lift the prints off the bed?

I do the same thing to get them to lift off the bed, but without the glue on my taz 5 they come of not to bad it is with using the glue that makes them very hard to get off.

The initial nozzle height can affect the adhesion of the first layer. If the auto-level fails, the initial nozzle height can be too close to the bed. A dirty nozzle can affect the auto-level. While the default wipe is good, cleaning the nozzle tip with a plastic scrub pad manually at extrusion temp is best. What filaments are you printing?

Can you post a picture of your print bed? Just want to understand “PEI tore”. I’m guessing it just means the PEI is split somewhere in the middle of the bed…

As for the glue stick, there only a few filaments where its necessary. Nylon, TPU (Ninjaflex) come to mind… for ABS and PLA, you shouldn’t use the glue stick. Adjusting (increasing) the Z-offset (through the slicer or firmware) will reduce adhesion and help print removal.

It’s odd. Some info indicates that the glue is a release agent that allows the prints to release more easily from the bed. And other info talks about it as an adhesive that creates a stronger bond between the print and the bed. In my experience, it is working more as a release agent. The prints take some force to release, but then the entire surface seems to release all at once which prevents the print from breaking under the pressure. Whereas without the glue, the prints were starting to break apart with pieces still stuck to the bed.

That Lulzbot provided knife/scraper is horrible. This is my favorite release tool -
It says it’s a 3D print removal tool, but looks suspiciously like an artist’s pallete knife…
These pallete tools are really thin and flexible.
Are you trying to remove your prints at the recommended removal temperature?
The bed needs to cool a bit before you try to remove your prints.
If I have a print that finishes overnight, it will often be released in the morning, just sitting loose on the cold bed.

Best regards,

The bed type makes quite a different. The PEI sheet on our printers have different adhesion qualities than plain glass, aluminum, kapton, blue tape… etc. Which may expalin the wide advice given about using glue, hairspray, ABS slurry… In general, the biggest issue for 3D printers is projects sticking to the bed. Not many surfaces require a release agent.

ABS and PLA should work great on the PEI with proper heat and initial extrusion temps. PVA glue stick recommended for filaments that adhere too much to the PEI… TPU and Nylon come to mind. If you’re prints are adhering too much, raise the initial height of the nozzle… usually .1-.2mm is enough to make a difference.

Some people like a super smooth bottom surface which makes a tool as recommended by PHugger very useful to get under the print for removal. The key is to slide the tool around the print and resist pulling up with the tool.

Thanks. Sounds good. But if you go to the Lulzbot store and the filaments, and then click on nGen, it say: “nGen adheres well to our PEI print surface. We strongly recommend applying PVA glue to directly on the print surface using a glue stick (such as Elmer’s® brand) before printing to ensure easy part removal.”

Is this documentation incorrect?

I was using the PEI without the glue for the first 20 prints or so, and then it started to stick harder and harder, until I broke a print, and then in trying to pry the broken piece off the bed, I tore the PEI… Then I started applying the glue, which does make it release a lot easier.

But are you saying I can achieve the same effect if I adjust the height of the nozzle? Is that the Z-offset? Can you set that in Cura?

Yes, the Lulzbot guidance is correct. nGen like TPU and Nylon sticks too well to the PEI. Therefore gluestick as a release agent helps. You could probably fiddle with the nozzle height and bed temp, but the initial layer results may not be pretty. :slight_smile:

I’ve never used nGen, so I don’t have much advice there. What happens when you extrude a little filament above a cold bed… does it stick? If it doesn’t then, then there could be some hope… I’d experiment with the bed temp until filament sticks, then work on a Z-offset for a nice bottom finish.

In the end the glue stick might be the easy button and save on a lot of headaches and wasted filament.

Regarding Cura, they removed the Z-offset setting for the TAZ 6… the offset can be changed through the LCD panel or gcode (the command escapes me at the moment).

Thanks for all the info. Much appreciated. When you change the Z-offset on the LCD panel, does that override the setting in Cura? I assumed it only worked if you ran the print from the LCD…

The LCD panel offset is stored in firmware, so essentially creates an artificial start height after the TAZ 6 auto level process. So yes, it should work with Cura.

Glad some of the info helped.