I was not happy with the 3m double sided tape method of attaching PEI

3D Printing
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I was not happy with the 3m double sided tape method of attaching PEI sheet to glass surface on my printers. I also need the PEI to not be transparent to activate the infrared proximity sensor I am using for calibration. I got the idea to attach it with high temp appliance epoxy spray paint. I tried. It failed. But it is an informative fail full of relevant data and it still may work.

I sprayed a nice even coat on the PEI sheet and placed the glass on it on a flat surface. I got air bubbles that proved to be impossible to press out. The round borosilicate glass bed I bought of Amazon is not all that flat and there was not enough paint to fill the gaps. I have it all setting up but I am sure the air trapped will heat up and make the PEI surface irregular at 70c print bed temp (a temp I often use for PETG 1st layers).

I can peel them apart and sand them/clean them and try again. I think it might work with a very thick layer of paint and then laying the PEI on the glass not flat but rolled on to squeeze out the air, then lay on a flat surface and let the paint settle and fill the gaps between. PEI should lay flat with the irregular low areas on the glass all filled with high temp epoxy stove/grill enamel paint.

How does this sound to you all? Nuts? Bad idea? Missing something in the process that will make it not work? The paint is rated for close to food at up to 1300f so it should be at least safe for vapors, right?

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Personally if cost isn’t a factor, I have never had issues with cshyde pei sheet. Best around IMO.

I think your issue is the glass itself. Either sand the glass (bad idea) or switch to something like MIC6.

Their pei is also matte finish so you shouldn’t have any issues with the sensor.

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Thinking about this paint, and the surface of a stove top with an enamel coating… maybe a sprayed on enamel print surface right on a thin spring steel panel? Sort of like what Prusa is doing, but without the PEI just printing on epoxy stove enamel? I have the can of it, might try to spray an even coat on something and see how PETG and nylon stick and if removal messes the surface up. It takes serious scrubbing in the kitchen without much surface damage…

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@Griffin_Paquette nice just found the company catalog I may get some. price isn’t the issue it’s the 3m transfer tape retaining gases that expand when heated causing slightly uneven surfaces using it. It seems a bit unreliable. Pressing really hard to squeeze the air out just makes valleys in the tape if it’s not even pressure using a wide rigid object with a smooth edge to not gouge the PEI.

that was my experience but I have only done it once.

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Prusa is apparently doing powder coating. I might try that on a printer at some point.

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I used an orbital sander to rough up the surface of the pei sheet a bit, 120 grit paper. It’s still smooth to the touch, but has an opaque matte finish. Prints stick much better, and that may help with your IR sensor.

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I would get rid of the infrared sensor.

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I painted the bottom of my pei black with high temp paint per instructions on dc42’s blog post on using pei with his ir Probe. I then attached it with 3m 468mp adhesive but I used 12x12 sheets of the adhesive applied to the pei staring at one side and applying it down at angle. I repeated the process to attach it to the glass / aluminum. I bought the 3m 468. 12x12 sheet on Amazon as a pack of 10 sheets, I think it was 10 sheets.
I found that using the sheet and the application method listed above helped limit the formation of bubbles and heat cycling the bed helped get out the small ones. I also used a roller to help lay down the sheet in both steps.
One thing to note, I moved away using the pei with the ir probe as I had to continually resurface the pei after removing prints as the imprint left by the print would affect the ir probe trigger height.

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thanks everyone. I sanded the PEI and cleaned the glass, tried again, there are bubbles and they make the surface color inconsistent. pressing the two together with a large 2" thick slab of acrylic, it’s ‘flat-ish like some people’s concept of the earth’… really not perfect like I wanted. Actually probably no better or worse than a bad 3M tape job like I did before but doubtful it will return IR readings consistently. I do like the PEI painted on one side it just looks nice (before messing it up trying to laminate with it). Might do that anyway with a touch sensor.

I am going to try a BL touch, see how that goes. IR will be in use on one machine so I will try out the admittedly bad paint lamination attempt and report back how many horrible bed crashes ensue :stuck_out_tongue: