TIP - Removing PEI Sheet from substrate

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zemlin
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TIP - Removing PEI Sheet from substrate

Post by zemlin » Mon Jan 29, 2018 4:22 pm

Have a well-used PEI over Aluminum bed that has started to release the PEI around the edges. The 3M adhesive sheet has dried out around the perimeter and doesn't have any stick left. The center however is still well bonded and I was not looking forward to trying to pull things apart.

Wondered if freezing would make any difference.

I put the plate in the freezer for a few hours. When I pulled it out I popped the PEI off with very little resistance, and only a few little spots of adhesive left on the plastic. 99% of it is still on the aluminum. I'll have to soak that with acetone to clean it off.

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insta
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Re: TIP - Removing PEI Sheet from substrate

Post by insta » Mon Jan 29, 2018 4:45 pm

If it's on the aluminum, can't you just burn it off? MIC6 will be fine in an oven at 500F for hours, just make sure it's supported.
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zemlin
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Re: TIP - Removing PEI Sheet from substrate

Post by zemlin » Mon Jan 29, 2018 4:56 pm

insta wrote:If it's on the aluminum, can't you just burn it off? MIC6 will be fine in an oven at 500F for hours, just make sure it's supported.
Depends on how my wife will feel about burning the adhesive off in the oven. Might get stinky.

Rich
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Re: TIP - Removing PEI Sheet from substrate

Post by Rich » Wed Jan 31, 2018 3:27 am

My late friend Sparky used to do both.

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zemlin
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Re: TIP - Removing PEI Sheet from substrate

Post by zemlin » Wed Jan 31, 2018 4:50 am

Image

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zemlin
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Re: TIP - Removing PEI Sheet from substrate

Post by zemlin » Thu Feb 22, 2018 6:04 pm

FWIW, I wrote this up on another forum - I should take the time to get some photos or video of the process, but until then:

I use 3M 468MP Adhesive Transfer Tape, 12" squares from Amazon to stick my PEI to the build plate. I use an aluminum plate, but the glass should work fine. I use a 3M 71601 Blue Plastic Squeegee to help lay the adhesive down. These also work great for applying Kapton to glass.

Getting the sheet down without bubbles can be a challenge, but with some practice it can be done. I put the adhesive sheet on the glass/aluminum first. I pull back the first release paper a few inches from one corner. I place the sheet on the CLEAN build plate and wipe across the exposed adhesive with the plastic squeegee working out about 10mm with each pass. I slowly peel back the release paper as I work my way across the platform until the entire sheet is down. When you're done you can check for bubbles. If you have any, slice through them with a razor blade and squeegee across them to eliminate them before removing the top release paper.

It's a similar process to lay the PEI down on the adhesive sheet. The plastic will have some natural curl to it. I find it works best to apply it so the edges of the sheet curl down. The center will bond the best anyway. The curl of the material helps the edges stay down.

Peel back the corner of the release paper. I use .06" 1.5mm PEI, so it's pretty rigid. I have to pull back about half-way across the platform before laying down the plastic. I do this diagonally. Carefully position the PEI and then push down on the first corner onto the adhesive. For this I wipe across the plastic sheet with a cotton rag pushing down as hard as I can. Working my way across the sheet again advancing a little with each wipe so I don't trap air. The release paper needs to be pulled a few inches ahead of the bonding point. If it gets creased between the plastic and the glass it can be very hard to pull out.

With this you should get your PEI down on the glass cleanly, and it will last for a good long time. The only caution I'd have is when printing ABS. Don't let the first layer go down TOO pressed. ABS can bond so it can be very difficult to remove and it's easy to gouge the PEI when trying to scrape the last bits with a razor blade. Softening the ABS with acetone can help prevent damage to the PEI. If you print ABS without excessive squeeze on the first layer (no flare if printing without a raft), it will pop off beautifully when done. I use 100C-105C for the bed temp on ABS. I go to 110C for PC.

I sand the surface of my PEI with 1500 grit sandpaper. I use an electric orbital sander for that. The light buff adds just a little bite. More is not better. I tried 800 once and that was too coarse.

Over time the adhesive will dry out and lose it's stick around the edges - but this will take some time. If you want to remove the PEI, stick the plate in the freezer for a couple hours. You'll be able to pop the plastic right off when it's cold. To clean off the old adhesive I put the plate in a large zip-lock bag with a little acetone and let that sit for a couple hours. Most of the goo will slide right off. If the adhesive has dried out around the edges, that will take a little scraping to get it cleaned up.

jferguson
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Re: TIP - Removing PEI Sheet from substrate

Post by jferguson » Fri Feb 23, 2018 4:16 am

Thanks Karl. Good description of how to do it.

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