PEI Film Woes

I used my Lulzbot Mini for about a month and then I started having issues with prints not sticking to the bed. After speaking with customer support they recommended using 10% IPA/Water mix and a high grit sandpaper to lightly roughen up the surface. After doing this, the prints stuck great for awhile but then the PEI film started bubbling up in some areas making it nearly impossible to print.

Question is, how many hours of use is reasonably expected to get out of a sheet of PEI? Didn’t seem like mine lasted that long and Im not a heavy user.

Also, does anyone know if the box comes with a replacement film? I could have sworn it did but can’t seem to find it in my supplies. I could be remembering wrong though.


Last question first – No, the printer does not come with a spare PEI sheet. They are about $25, available from Lulzbot directly, Amazon, and various other suppliers.

I am on my third PEI sheet, so I’ll give you my experiences…

My first PEI sheet started getting bubbles after just 3 weeks of use. I had not been real careful about removing prints at 50-60C, sometimes allowing the bed to fully cool to room temp, and Lulzbot Tech Support pointed to that as the likely reason for bubbles. But they still sent a complete replacement bed with PEI under warranty, and I installed that.

That replacement, with me being super-careful about always removing parts while the bed was 50-60C, lasted about 3 months before starting to bubble.

I bought a 3rd replacement PEI sheet directly from Luzlbot, and replaced it myself. I also bought a very thin, wide painters knife to remove parts. I have been printing on that sheet for 7+ months, and it still looks like brand new with no sign of any bubbles.

Now it is possible there was something wrong with the first two sheets, like bad adhesive or something. But I think most of the longer life with the 3rd sheet is attributable to always removing at 50-60C, and using a very thin painter’s knife, held flat to the bed, to remove prints gradually without a lot of force. Another contributing factor MAY be bed temp; I initially used HIPS and ABS exclusively so the bed was always at 100-110C. I gradually started using PETG/Nylons about half the time, with the bed around 75C, so the lower temperatures may have something to do with longer life as well.


That’s very useful information, thank you. I started with HIPS and ABS as well, and found after much frustration that PETG was the way to go. I’ll give warranty a call and see what they have say.

Thanks again!

I know around the time I bought mine (4Q 2015), there were a lot of people reporting bubbles and replacement under warranty seemed to be pretty common. I believe AO subsequently changed how the adhesive was applied, using a heat process, and that seems to have greatly reduced the failures. The PEI is now generally viewed as a “wear and tear” item, and warranty replacements are less common. But if yours is only a month old, and you’ve followed proper removal (not “prying” but separating, and doing so while 50-60c), then AO may conclude it was a defect and send you a replacement film. Certainly worth a call!

I eventually bought a complete spare bed assembly – glass, heater, PEI – to have on hand. I figured that would allow less down time for the next time the PEI needs replacement, since I can just swap in the spare bed, start printing, then replace the PEI on the other one at my leisure. I also decided it would be good to have a spare heater, thermistor, and glass on hand in case any of those failed.

Good luck and happy printing!

No luck with warranty replacement here. I talked to customer support and emailed them pictures and they said it wasn’t warranty item, because the bubbles were caused by improper removal of parts. I always made sure to remove the parts at the recommended temperatures. Oh well, I bought a new one that supposedly has an improved adhesive on it. We shall see how it goes. Thanks!

Sorry to hear that… But hopefully your luck with the replacement will be as good as my 3rd one – it has been “going and going” {imagine graphic of Energizer Bunny here}, and still looks like new. Only maintenance has been to lightly sand it with 1500grit a few times.

Did Lulzbot Support mention the “improved adhesive”, or say when they started using it? Perhaps that’s why my 3rd one has done so much better, although I bought it ~June-2016, so if that was the case then I would have expected your machine to have had that from the start.

I’ve had mine for a year and the PEI sheet has had bubbles for ages. I haven’t had any issues with prints sticking to the bed, quite the opposite actually. My most recent ABS print stuck so well that I think ripped a hole in the PEI sheet when removing it. At least now I have a place to push the air bubbles out.

On a side note, I recently saw a print bed that used a mirror instead of regular glass. It looked freaking awesome so it I ever end up getting a second setup like ScottW, I’m going to source out a chunk of mirror to stick the PEI sheet to.

I have found that if you are printing to close the PEI, the parts stick “to good”, need to make sure that you calibrate your z-axis. Also I started using blue painters tapes over the PEI, do not need it for non-sticking, but it makes the first layer more of a matte finishing (with ABS, have not tried any other filaments) and I like the look. My current PEI is 6+ months old and no real issues, except it is starting to get some small imperfections in it and sometimes these show up as small lines or dimples. The painters tape also helps hide these. First PEI had to be replaced from having to pay “stupid tax” (removing parts with sharp object and not paying attention to bed temp).

I suspect my cause of bubbles is either the initial adhesive or the initial installation.

All of the bubbles under my PEI are on the back third of the bed and the majority of my prints do not cover that area. I’ve only been printing with my TAZ 6 for about 5 weeks.

When it becomes a sinficant enough issue, I’ll replace it myself. I did the install of PEI on my other printer and it’s been fine for 6 months.

This is good info.

In contrast with so many people who had problems trying to get their print to stick to the bed, I had a tough time attempting to remove stubborn prints from my bed. I had read suggestions in the forum about heating the bed to about 60-80C (just below the glass transition temperature of nGen, the material I was printing with). It worked. My prints came off much easier while the bed was warm instead of room temperature.

So, I think most of the bubbles you’ve been seeing have probably been caused by the strain of removing the prints from the bed. The heating of the bed softens the material slightly and thus relieves some of the strain.

Its a win-win: Not only do our PEI sheets last longer (news to me from reading this thread) but our prints will be easier to remove.

Hey there,

At what temp does the bed slide forward after a print is done? I had thought that it was when the bed reached room temperature. Is there a gcode modification that we could keep the bed at the “right” temp for a while after the bed is slid forward



It varies by material, but generally around 50C for most. In general, you can edit the ending script to remove the “S140 S0” that turns off the bed heater, or insert a dwell command (G4 Sxxx, where xxx is number of seconds) before it, so that the bed stays warm. This question comes up pretty frequently, so search the forum and you should find a bunch of example script changes that implement this.


The PEI sheet gets lumpy after a few prints

Would like to replace it with solid glass print, so that prints always have flat botom

DO you just run un-heated if you do that then? cause when i went to remove the lulzbot mini petg, it has wires connect to it, cant remove etc.

The standard Lulzbot beds have the heater adhered to the underside of the glass. Best way to remove the PEI is – disconnect the heater (plug is generally zip-tied to cable chain under bed) and put the entire assembly (heater, glass, PEI) into the freezer for 30 minutes. Take it out, and the PEI will peel right off, leaving the adhesive behind. Then use alcohol (or Limonene if you have it) to soften the adhesive, and scrape it off with a razor blade. Takes a while, but it eventually all comes off. You need to be careful not to damage the heater while doing that.

Not sure about printing on the bare glass, as I have no experience other than what I have read…which is that you will generally still want it heated. Some materials don’t stick well to glass and will need some form of adhesive layer (tape, abs slurry, pva glue, etc.). Other materials may stick too well without using something like PVA as a release agent. I recommend visiting some sites that sell plain glass beds, and look for recommendations there.

thx scott. ima print nylon 910 mostly with glue stick and the sooner i get rid of the pei trash the better.

Cool- For glass, Taulman recommends 45C bed with PVA when printing 910. See the link below for more details. The A910 is really great stuff - just make sure it is really dry, as any absorbed moisture will cause bad layer adhesion and popping/bubbling. If you have any trouble, Taulman is really responsive and helpful.

for sure. 910 is mother i been layin down battlebots with it for a couple yera tho so no problem.