That was one of the reasons I bought the replacement sheet for the school’s Mini with the adhesive pre-applied. I’d never worked with it before, and figured that was one less thing for me to screw up. (I also figured getting it to adhere well to the glass was probably easier than getting it to stick to the PEI.
To remove the adhesive, I used “Rapid Remover”. Among other things, it’s designed to remove the adhesives used to apply decals and graphics to cars and vans. It was recommended by either Lulzbot tech support or I-T-W, I forget which. It worked very well: peel off the old PEI sheet, spray this stuff on, let it sit for 60 seconds then wipe off or use a razor-blade scraper. (I actually re-applied and repeated the process to get everything well cleaned.) Then I went over the glass with an isopropyl wipe to make sure I had gotten all the Rapid Remover off. Some Wallmarts stock this, but not the one near me, so I ordered from Amazon. (I ordered something close to a quart bottle, but that’s probably several lifetime’s supply for me. I should have ordered the 4 oz spray bottle.) I’m guessing there are similar adhesive removers sold in many hardware stores.
Thanks for response mhackney. I was absolutely as meticulous as possible. All previous adhesive removed from glass and from PEI. All surfaces cleaned 5-6 times with isopropyl alcohol (91% pure). Using only microfiber cleaning clothes. This is exactly the stuff I bought from Amazon. Amazon.com: 3M 468MP Adhesive Transfer Tape, 12" squares, Small, Clear (pack of 6) : Industrial & Scientific. I’m beginning to wonder if these pieces of 468MP are somehow in a degraded state.
Take a look at the video below… This is after just 24 hours from it being put on. You can see how the adhesive isn’t perfectly bonded to the PEI. But trust me… I used a squeegee and didn’t touch any surface with finger tips… The PEI sheet is basically new (just a few months) and is perfectly flat. No dust or debris got in between as I was applying the adhesive… It’s just simply not sticking like I think it should. Doesn’t that seem like the culprit is the pieces of 468MP I have??
Looking at your video, that’s not normal 465mp adhesion at all. I’d suspect bad adhesive. One thing you could try is rough up the underside of the PEI sheet to give the adhesive more surface to bond to, but even then, it’s just not sticking like normal. You might try cutting out a small section of a different sheet, sticking it to a top edge with something heavy sitting on it overnight, and see if it adheres. High humidity can also affect the adhesive. With the disclaimer of “I have no idea if this will work and it might catch on fire so don’t do this” you might want to stick an adhesive sheet in your oven on the lowest setting it will go for a few minutes and see if that improves the bond. Or maybe stick the sheets in a sealed plastic tub with a pack of silicon dessicant for a week or so?
I agree with piercet, that is very unusual. What is your bed temperature when this happens?
It’s either the 468MP or something on the surface of the PEI. You did remove the plastic protective sheet right? Just kidding, I’m sure you did. This could be silicone contamination, iPropylAlcohol is not effective for silicone removal, try acetone.
It doesn’t ‘happen’ at a specific bed temp. It’s just always continually and slowly separating over time. It gets worse and worse over a period of weeks and I rub over the bigger trouble spots whenever I print which is multiple times per day. And in the vid the bed was heated, and yes it sticks down better when it’s warm but it won’t stay down. I usually print with ABS with a bed temp of 110C and less frequently print with PLA at a temp of 60C. Again, what you saw was just 24 hours after I put a brand new 3M sheet on.
Not sure if I mentioned this earlier but I used the citrus based ‘Goo-gone’ on the back of the pei sheet to clean it after I removed it from the bed. BTW, i’m calling the slick side the ‘back’. I put the matte side up to print on. But as mentioned before, i used ample (and numerous treatments of) isopropyl alcohol to clean all surfaces after the initial goo-gone was used to get the previous 3M sheet off.
@mhackney What do you mean by silicon contamination? Is PEI adverse to silicon for some reason? I’ve never gotten any silicon based products around it to my knowledge.
Is acetone safe on the PEI sheet? I used some to clean the glass plate when I replaced my PEI sheet, but the sheet itself was trashed, so I never cleaned it, just threw it out and put the new one on.
BTW… a tip for removing the old PEI sheet (either LB or I-T-W tech support passed this on to me): Put the print bed in the freezer overnight, then remove the PEI sheet the next day. It comes off much easier. It was about 5˚F outside, so I just put mine outside for a couple of hours. Since this was my first one, I have no idea whether it was noticeably easier or not, but the PEI did come off without a lot of struggle (in fact, about 1/3 of the glass plate came out almost completely clean, with the adhesive in that area all sticking to the PEI).
You will need to make very sure you get all traces of the Goo-Gone off the PEI sheet. The 3M will never stick with that on the plastic, that is like rubbing oil all over. The short exposure of Acetone will not hurt it for cleaning off the oil.
@paulmorley silicone is a common lubricant and notorious for causing issues with adhesives and paint. But I think we found the smoking gun - goo be gone. Great stuff but a bugger to remove all traces. Acetone works well though and if used sparingly will not harm PEI (i.e. don’t soak the PEI in acetone overnight). Do a final rinse with iPrA and you should be good to go.
It’s like soapy water, but misspelled because my downstairs tablet keyboatd is dumb.
PEI is not reactive to acetone, and as long as it isn’t one of the brands that has oil in with it, it should be fine. Acetone alone probably also won’t eat the silicone oil though if thats what the issue is, soapy water should break it down though.
I tend to have “creative” spelling under the best of times for things, but my LG 410 tablet that I use downstairs literally has a haunted keyboard, so it tends to have a mind of its own when it comes to certain words. You can pretty much tell when I’m using it if you go back and look for the posts that have been edited 40 times immediately after posting. One of these days I’ll upgrade it to a better one, but it was free with my phone so I can’t really complain about it too much heh.
ok. You guys have convinced me to redo it once again. And this time, i’m gonna record the process and compile a video. At least for some it will help to see the process.
And I used the freezer trick as well btw. But it doesn’t need to stay in the freezer anywhere near that long (overnight…). 15 mins does the trick. The magic is that it just need to be very cold. Hopefully I can post the vid by Saturday when i’m back home from a business trip.
