I'm A Convert! PEI Heated Spring Steel Bed Plate Surface

I started my 3d Printing journey using blue painters tape on a bare metal bed.

I then converted to using gluestick on a cold glass bed: https://www.printerknowledge.com/threads/bed-adhesion-tricks-and-tips.12128/page-9#post-109242

This worked great for years. Biggest issue was getting really large (surface area against the bed) parts off the glass without breaking the glass, my bed, or stabbing myself with the scraper.

I then tried a magnetic sheet, but wasn't happy with it (probably partially due to low-quality magnet and sheet): https://www.printerknowledge.com/th...sted-new-magnetic-flex-sheet-print-bed.14464/

... and went back to cold glass / gluestick.

Again, mostly happy with it, except for large parts.

Well, after seeing TONS of videos with guys using PEI on spring steel sheets, I decided to order one. I decided to "splurge" and get the double-sided sheet with smooth PEI on one side, and rough / powder-coated PEI on the other:
https://amzn.to/33KFKgS


I've been experimenting with it for about a week and am VERY happy with it!

There's still a part of me that doesn't love waiting on a heated bed to warm up (heck, I get frustrated waiting for the nozzle to heat), but I think the Ender 3 V2's smaller bed AND 24 volt system (with the sheet metal vs. fat glass) heats up way faster than my CR10 big bed, 12v, thick glass, so I may start always printing with <gasp> a heated bed! </gasp>

... that said, I still like experimenting, so I've been playing with combinations of bed temps on the smooth and rough sides, as well as using and not using gluestick.

I found that the textured side needs at least 60 deg. for the parts to stick and then do the magic self-release when cold.

The smooth side is more forgiving and I can get a decent "stick" at 40, and even 30 deg.

I might still do cold bed + smooth-side-PEI +gluestick on small quick prints... which is like 90% of the stuff I print, and then do a fully heated + rough-side PEI for really big / long-duration prints.

All-in-all, more fun stuff to experiment with!!!

Welcome to Peiland..
My 3D jpurney started with a steel PEI sheet, No experience with glass bed but I don't think I missed much.
If your PEI sheet is clean of grease residues and the Z level is well tuned, you shouldn't need any glue at all on the smooth side, provided your bed is heated up to 50-60C. That's what 'experts' at Prusa forum say, but I found out that using 3Dlac (hairspray with a fancy name) helps a lot, even if the surface isn't spotlessly clean.
Glue stick is fine too but much more difficult to apply on a thin even layer. The bottom of the print never looks smooth and if you use too much glue, it's rather messy to clean it afterwards.
PEI sheets really need a bed heated to some extent. I never tried PLA with a cold bed but I suspect that warping might be an issue for large models with sharp edges, even with lots of glue.
Cheers.

I haven’t used the steel PEI sheets yet, but as long as the blue magnetic sheets last I’ll stick with them for now, the other CR-10 has (Kitchen Chopping board) rough glass and I reckon that’s the most reliable surface I’ve ever used.

Having the two CR-10’s allows me to try out different bed surfaces without disturbing the other one that’s on glass, and no matter which bed type I use once the surface is clean and sprayed with a tiny bit of 3Dlac spray, none of my prints lift.

The only issue I get with the blue magnetic sheets is they lift on the edges, because the magnetism is not strong enough to handle larger prints down, so I use bulldog clips on the 4 corners.. (Not always successful)


I run all my printers with the same bed temp of 45c, and yes the 24 volt printers do heat up very fast, so there’s no waiting, but the older 12 volt machine take an age to heat at about 6 minutes before a print commences.

I’ve stopped using glue sticks altogether, because I had the same annoying results as @Artur5 got with lumps of glue sticking to everything and messy to remove later, I’ve only been doing small prints lately but maybe later on, I might invest in a proper steel magnetic sheet..

The only thing that’s stopping me from jumping in and getting the steel plate is how well it will stay stuck down to the bed with larger prints, is the magnetism powerful enough to do the job… !

On my printer, the steel plate isn't magnetic by itself. What keeps it stuck to the bed are the magnets glued on the underside of the bed. I think there're 20 magnets and they keep the plate firmly attached. No risk at all of getting loose, you have to pull really hard to remove the flex. steel from the bed.
How do you keep attached the blue magnetic sheet of your CR10 ?

I agree with 3DLac; it works very well and serves too as a separation layer for filaments that stick so hard to PEI (PETg. Flex) that it would be very difficult to remove the models from the bed, if printed directly on the PEI surface.

The Hat said:

The only issue I get with the blue magnetic sheets is they lift on the edges, because the magnetism is not strong enough to handle larger prints down, so I use bulldog clips on the 4 corners.. (Not always successful)

Click to expand...

Yup, I had the exact same problem with the same flex blue mag sheet.

The Hat said:

The only thing that’s stopping me from jumping in and getting the steel plate is how well it will stay stuck down to the bed with larger prints, is the magnetism powerful enough to do the job… !

Click to expand...

From what I can tell, the "stick" between the steel plate and the mag sheet (that used 3M adhesive to stick to the bed) is way WAY stronger than the flex sheets. In fact, when I start laying the steel sheet down, once it gets about 10mm from the mag sheet bed, it is pulled down with great force. I'm not at all worried about it ever flexing and pulling up like the blue flex mag sheet.

Nifty said:

From what I can tell, the "stick" between the steel plate and the mag sheet (that used 3M adhesive to stick to the bed) is way WAY stronger than the flex sheets

Click to expand...

That’s good news, but I still might get magnets to glue under the hot bed as @Artur5 suggested..

The Hat said:

That’s good news, but I still might get magnets to glue under the hot bed as @Artur5 suggested..

Click to expand...

I'll bet you a beer you won't need any additional magnets!

If you stick the magnet that comes with the kit to a properly clean / prepped bed, the metal flex-plat should grab on SUPER well to the magnet.

I look forward to hearing your experience!

Oh, and a fun side-note: I have the mag sheet from my CR-10 sitting next to my printer. I realized I can take the PEI flex-plate from my Ender3 and put it on the super cold magnetic sheet, and the cold sheet will QUICKLY suck the heat out of the flex metal PEI sheet.

Kinda fun to watch as the bottom layers quickly cool and release... especially thin layers with my semi-translucent filament.

In this pic you can see the lighter areas of the squares is where it already self-released. When hot, they were all "darker", and then started self-releasing as the bed cooled down. Pretty neat!

Just to clarify: I didn’t glue magnets under the hotbed of my Prusa. They come already glued in place on the original hotbed because the printer is intended to work with flex steel plates.

If somebody wants to add magnets on the bottom side of a hotbed, I expect that they need to be glued really well with an adhesive able to withstand up to 110-120C without softening or falling apart. Ordinary cyano-acrylate glue probably wouldn’t be good in these conditions. Time ago I read on the Prusa forum that several users had some of those magnets fall, apparently due to a defective batch of the glue used by Prusa. This was with the former version of the printer (MK3). Mine is a MK3S+ and 'should' be free from trouble (fingers crossed ).

The ‘gurus’ of the forum suggested ‘J-B Weld 82655 original cold-weld epoxy’ as the better product to use for this task.
I remember the reference because I wrote it down, just in case some of the magnets of my printer decide to 'leave the ship' . In fact, they usually don’t get really lost. After falling, they get stuck on the iron rods or the steel frame of the bed.

Yup, 100% what @Artur5 said:

1. Prusa comes with them attached (like this).
2. Adding magnets to another printer would be a nightmare
3. It won't be needed. Millions of people are using the metal flex plates with the supplied adhesive magnetic sheets without any problems with them lifting up.