Cleaning the PEI flex steel print sheet

The Prusa i3 Mk3 printer ships with a PEI-coated flex steel print sheet. The surface has excellent adhesion properties for most materials, but does require some basic maintenance. Without good first layer adhesion, you’re going to have a difficult time achieving good print results. It’s worth spending some time getting familiar with the bed characteristics when starting out.


These notes apply to the Prusa i3 Mk3 printer. If you are using a different printer, please verify the hardware details are same. These pages may be a bit rough as I revise them and add new material. Please check back regularly for updates.

Routine bed cleaning steps

The key to good first layers is to keep the bed clean and avoid touching it. If adhesion starts to weaken, try these steps in this order:

  1. Wipe bed down with 91%+ isopropyl alcohol. Do this regularly but not necessarily every print. Definitely do this immediately after you’ve handled the sheet.
  2. Wipe bed down with 100% acetone. Perhaps monthly. Acetone is tough on the PEI surface, so don’t over-use this option.
  3. Wash under sink with dish soap. The previous methods are good at removing grease. This will wash away anything else that may have accumulated. Repeat when wiping with alcohol or acetone fail to help.
  4. Rough up the surface. Use a very mild abrasive pad and very lightly rough up the surface. I like the 3M Scotch-Brite 7445 pads. Obviously, don’t do this too often.

The most important thing is to keep the bed clean and avoid touching it at all costs.

  • Take advantage of the removable flex surface to pop prints off.
  • Use a non-metallic scraper to help lift prints that stick a bit.

If you’re careful, won’t need to clean the bed every print.

Finishing up

Above all else, try to avoid touching the print sheet. Use a non-metallic tool to help remove stuck prints.

Contact and feedback

You can find me on the Prusa forums or Reddit where I lurk in many of the 3D printing-related subreddits.

Last updated on Dec 11, 2018