Replacing your PEX Build Surface
I give 5 stars for the surface, and 3 stars for the process. The process of replacing your build surface is not for those in a rush. It took me several hours, and will likely take you that long too.
First, the reason that I needed to replace the build surface was when I printed PETG and PETG-FG on my original PEX build plate. There were two issues that occurred. First I had a strain gauge failure that caused my hot end to drive into the plate. This left a divot in the PEX because at the time, the temp of the H/E was above 250°C. The second issue was when I printed PETG-CF. It adhered too well to the PEX and removed small areas from the surface.
I watched the video online and chose to use Goo Gone rather than acetone to assist in removal of the PEX surface. First, I put the plate in the freezer for at least 30 minutes. Even so, it was difficult to get underneath the film, but once I did, I was able to get a (new, flexible) drywall taping knife under the edge. With the plate still cold, I was able to wrestle the film off after about 10 minutes.
What was left on the plate was a thick layer of 3M adhesive that took several hours to remove. I soaked the surface in Goo Gone and let it sit for 30-45 minutes. This swelled the adhesive, and I was able to scrape it off using various putty & drywall knives. It took 6-8 iterations of this to completely remove the adhesive. In the process, I ended up scratching spring steel in numerous places. It does not look as good as before but has not affected the functionality. I recommend using a brayer when placing the new surface, to eliminate bubbles. I didn't have one, but it looks Ok. Before using, it placed it on the bed at 50°C for 30 min, then 80°, followed by 100° for the same amount of time, before printing.
To prevent future failures when printing PETG (or PCTG), I now use Layerneer Bed Weld when printing these filaments. I have successfully used it on PEX, but more commonly flip the plate and print directly on the steel side.
If others have replaced this film with less hassle, I'd like to hear details. While going through this process, I thought it would be easier to just buy another spring steel plate and use the build surfaces that I got on sale.
