R2 Print Bed

After messing around with the Print Bed for a little bit, I figured out a few things:

The four covers on the top that are covering the screws that sandwich the heater to the aluminum underside are glued on. They will also bend if you try to pry them up. So there will be no removing the heater. I guess we can just throw the whole thing into the freezer, remove the PEI, use Goo Gone/Acetone/Limonene to remove the adhesive. Since the PEI sits directly on the aluminum, it should be a lot easier. Hoping to try this on Thursday when my adhesive transfer sheets arrive from Amazon (bought the PEI but forgot the 3M sheets).

 

My adhesive is coming tomorrow, so I decided to try to remove the existing PEI tonight. I threw the bed into the freezer for about 40 minutes. Unfortunately the PEI didn't come up very easily. I had to cantilever the scraper that the printer came with and you could hear the PEI start snapping up. I got about half of it up before I couldn't pull it anymore. I let the bed thaw out a bit and then I could pull the rest of it off the bed.

Most of the adhesive was removed with the PEI sheet. There is a corner of adhesive left to remove with Goo Gone.

The bad news is some of the paint on the aluminum was scraped off as you can see a couple of strips of silver showing through. I'm sure it wont matter once I have the new PEI sheet on it.

Interestingly, the existing PEI was tinted underneath which gave it that dark glass look.

Anyways, my suggestion is just skip the freezing and pull the existing PEI directly off the aluminum. Try to minimize the amount of scraping so you don't ruin the paint on the bed. Just use Goo Gone or alcohol to remove the adhesive that's left behind on the bed. I think I'll eventually buy a new bed once they go on sale.

I've uploaded an image so you can see what it looks like without the PEI sheet.

 

After a bit of effort, I ended up getting the new PEI sheet onto the bed. Damn those 3M transfer sheets are sticky.

The only issue now is that since the PEI sheet I have isn't tinted, you can see all the scrapes and bubbles underneath the PEI. I'll be glad when Robo starts selling replacement PEI. Also, the PEI that the R2 came with was slightly larger than 8x8. When the R2 does the priming strip, it misses the PEI.

Again, when you replace it, don't freeze it. The adhesive will stick more to the PEI than it will the Aluminum, so there's no need. If I hadn't frozen it, I probably wouldn't have had that big chunk of adhesive stuck to the bed. Just pull the PEI up slowly, using the scraper to push through and cut the adhesive as close to the bed without touching it as you can. You don't want to scrape up the aluminum bed as the paint comes off easily.

Once the PEI is off, put a paper towel on the bed and pour some Goo Gone on it to cover the bed. Wait about 10 minutes, remove the paper towel and then start rolling the adhesive up like you would roll up rubber cement. Then use some alcohol to clean the surface and repeat until the adhesive is gone.

Then you put the transfer sheet on the PEI very carefully and then stick the PEI to the aluminum very carefully.

I did a test print (fidget spinner) and it's working perfectly again.

 

This is a fascinating thread, thank you everyone. I am very disappointed that there was no warning about how PEI works as many of you mentioned. I have been using the scraper included with the R1+ and again in the box with the R2 and have become accustomed to using a lot of force and sure enough, after my first print I destroyed the R2 PEI. I tried to put another sheet over it, but I have a feeling PEI over PEI doesn't work too well as there is just too much opportunity for things not being flat and not enough heat coming through. So I now too will have to do the above steps to remove the R2 PEI. I did ask Robo if I should do this and I haven't heard back, so I'll just do it.

I don't particularly want to turn off the auto-bed leveling with Gcode/octoprint, but the PEI I bought is Gizmodorks and it is tinted yellow, not black. So does that throw off the IR sensors or have others been ok with the new PEI sheet that isn't black?

This is definitely not for the faint of heart and certainly not "prosumer" in any way in my opinion.

Thanks.

 

FYI, I heard back from Dave at Robo and he sent me an invoice for their PEI sheet which I just purchased so there was no chance of the black vs clear issue with the IR sensors. It was 00-0962-COM - R2 PEI Sheet .8x220x220 × 1 and $18 or so.

 

FYI, I did get a new black PEI sheet from Robo, but I wanted to mention that when I had to get my old one off, I didn't freeze or heat the bed, but I just scraped off the glue, but I used the attached tool which I think is a paint or wallpaper scraper and it was awesome. That combined with goo-be-gone and it worked great, but the leverage this tool has is perfect for this. Just FYI.