Adjusting the stickiness of PEI (scroll down for tl;dr) Quick Intro: PEI is awesome,

3D Printing
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Adjusting the stickiness of PEI
(scroll down for tl;dr)

Quick Intro:
PEI is awesome, if you are even slightly unsatisfied with your current build surface give it a go. Unlike many print surfaces, its extremely hard and resistant to damage (I’ve even nozzle scraped a few times and there’s no damage!). This means it has almost the longevity of glass and yet it sticks to PLA and ABS without the need for glue, tape, hairspray, etc. End result - a clean maintenance free surface!

My Experience:
However when I tied it I was baffled… Most people were saying “it sticks too hard” and yet for me, although it was holding the PLA prints in place it wasn’t even sticking well enough to prevent curling (see image below)?

Searching For A Solution:
I scoured the forums and tried all the common suggestions from PEI users; “clean it thoroughly with isopropyl alcohol”, “print closer to the bed”, “increase the bed temperature”, “sand it down with 1000 grit paper” - None of them worked, not even slightly. I even found a couple of other people with the same problem as me but alas, no answer.

Eureka!:
Then it suddenly occurred to me…
People often said to remove the prints you must make sure the PEI is cold because when its warm its too sticky to get the prints off. It seems logical that this could mean the reason PEI works is because it gets stickier near its glass transition temperature which is 217c. Whilst that’s nowhere near the bed temperature, it is suspiciously close to the nozzle temperature for PLA and less than the nozzle temperature for ABS (which sticks harder to PEI than PLA).

So that’s why I was having problems!
At 185c the PLA I was using was at a slightly lower temp than average! I changed the first layer temp to 200c, bingo it stuck perfectly!

tl;dr:
I still have some experimenting to do but so far it seems the stickyness of PEI is directly related to the first layer nozzle temp. If you want your print to stick harder, turn up the temp. Finding it too difficult to remove? Turn it down a notch…

I’ve not seen anyone else talk about PEI adhesion in relation to nozzle temp, so hopefully this will help other people who had similar problems to me and also help others who are successfully using PEI to dial it in better.

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I’ve personally never had problems with just 3M blue painters tape (with a wipe down of alcohol if the print has fiddly bits I want to be 100% sure get stuck down), but I do find all these new build surface approaches fascinating.

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PEI works for me on just about anything, including a handful of experimental materials. Nylon is the lone exception for me. I’ve been using the same sheet for at almost two years now, I did flip it and apply new adhesive.

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So how thick is the PEI sheets most people use? I use buildtak but I would like to give it a try.

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People generally use 0.03-0.04" thick. or just under 1mm thick. And use 3M 468MP adhesive. But I heard double sided carpet tape works well too.

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@Jeff_DeMaagd the carpet tape works good for a cheap fix. But let’s go at 90C. So for PLA and PETG bed temps it works great. But is a no go for ABS temps.

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Ouch, well scratch that, then.

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Great observation! I use PEI for a lot of different materials without issues, including a lot of nylons and co-polymers. I use a light coat of PVA gluestick for nylon and ABS to help getting the print off the bed by just spraying a little water at the base of the model and gently getting a blade under it. PEI transformed my printing experience completely. I’ve tried several adhesives to stick it to the bed, and 3M 468mp is the best by far. If you ever have to get it off, WD40 works fairly well, followed by cleaning with acetone. To clean the PEI I generally use IPA alcohol between prints. cooling before model removal is essential.

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+Daniel Bull​ Where did you source your PEI? I’ve seen it on eBay and Amazon but it comes from the USA and shipping charges are insanely high.

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@Neil_Darlow ​​​ I know it’s really hard to get in the UK :frowning: @Ryanteck_LTD ​​​ https://ryanteck.uk were going to be a UK stockists and got some Ultem samples in to test but unfortunately the minimum order quantity was just too high so they had to give up on the idea. I said I would help them promote but they would have to sell almost 1000 sheets to break even and I think even with your guys help we would struggle to manage that :frowning:

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PETG on PEI seems to be a hit or miss for a lot of people. I’ve yet to ruin a PETG part or the build surface getting it off but I don’t know what I’m doing differently from other people.

I did a vase with a 150mm base two weekends ago and a couple 190 x 110mm parts just last weekend, and I was apprehensive because of this reputation. It stuck well but it did come off cleanly. It might be motivation to try a video to show what I’m doing and see if it helps anyone.

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CS Hyde Company is a good supplier for PEI because they sell sheets with a high temperature 3M adhesive backing already applied! I have used the 5 mil thick sheets, 20$ for a 12" x 12" sheet.