need to re-coat both sides of two of my smooth PEI steel sheets  

RE: need to re-coat both sides of two of my smooth PEI steel sheets

You can certainly buy replacement PEI sheets for the Prusa spring steel sheets. However:

Removing the old PEI is a PITA. I wound up spending a couple of hours soaking the sheet in limonene and scraping. The Prusa spring steel sheets also show oxidation quickly, so there are spots under the replacement PEI. This doesn't affect printing at all, but it is unsightly.

You shouldn't be destroying PEI sheets on a regular basis, even with PETG. I have destroyed 3 PEI surfaces in 3 years. The first was due to my own ignorance when printing high-temp 270C PETG. The others simply due to abuse during the COVID printing push. My first Prusa surface is still in good shape after 3 years of mixed PLA and PETG printing. Are you using Windex, finger wipes, baby powder, or glue stick as a separator before printing with PETG? Give the bed a good clean (for evenness) and apply some separator, and PETG should pop off cleanly. You might also consider one of the commercial adhesion products. Here's my PEI sheet that was damaged from the high-temp stuff showing the same parts printed with the same material popping off easily after applying MagiGoo (same sheet as above before repair).

You can buy replacement spring steel sheets and PEI surfaces from Prusa. I have found that I much prefer the thinner spring steel sheets sold by PrintedSolid with the PEI surface sold by BuildTak. BuildTak uses an adhesive that is much easier to remove than Prusa's (3M I think).

If you are printing a lot of PEI, you might consider the satin or textured powder-coated sheets. They are more durable and work well with PETG in most (but not all) cases.

RE: need to re-coat both sides of two of my smooth PEI steel sheets

@bobstro

Much appreciated Bobstro.  I just now started applying glue stick to my last good surface on my last good PEI coated sheet.  It did help a whole lot in getting a large flat round PETG part to come off easily.  Wasn't entirely sure when/why to use glue sticks - I had thought it was for improving adhesion 😉  Adhesion isn't my problem for sure.    Also glad to hear that the textured sheet I have been holding in reserve until I understand why I'm churning through PEI sheets is probably better for PetG.  

I've heard that the PEI coating will come off more easily (for re-coating) if I put the steel sheet in the freezer.  Just ordered some low-cost PEI sheets w/3M coating from Amazon - experiment time.  Thank you for the recommendations for BuildTak and PrintedSolid.

RE: need to re-coat both sides of two of my smooth PEI steel sheets

Not to again risk the wrath of those who do not approve of the way I do things, but there is one product that I have found works well for almost all materials, particularly well on the smooth stock sheet, both as an adhesion enhancer and as a release agent.

It's the Layerneer Bed Weld.  It was originally intended for glass plates, but experience shows that it works very well on PEI coated plates as well.  It goes on with a much thinner coat than glue sticks.

I use it as a matter of habit with all ABS and PETg prints, and with PLA prints that have a small footprint or that use small fine supports.

PETg and ABS prints will pop right off with a cool-down and a gentle flex of the sheet.

No, I don't have any connection to the company or their distributors.  One of the others here on the forum turned me on to this and I've found it to be quite helpful.

RE: need to re-coat both sides of two of my smooth PEI steel sheets

Posted by: @jsw

Not to again risk the wrath of those who do not approve of the way I do things, but there is one product that I have found works well for almost all materials, particularly well on the smooth stock sheet, both as an adhesion enhancer and as a release agent.

If you added "... after cleaning and calibrating Live-Z", I'd have no concerns. If the bed underneath is too soiled, or if Live-Z has been adjusted too high, no amount of adhesion booster will help. I have just spent too much time with new folks who have applied glue and goop because they were hesitant to learn how to do the proper calibration and cleaning procedures. It's just that we have spent so much time and effort here communicating the importance of proper bed cleaning and Live-Z adjustment to new users that I want to make sure that message is not lost in the marketese from "products" that make it sound like just slathering on their stuff is all you need to do for perfect 1st layers.

I'm using Layerneer on my Sidewinder, and have used VisionMiner and MagiGoo adhesion products on it as well. I've used MagiGoo on the PEI without problems. There are times when they make sense. Of the bunch, VisioMiner seems to need the least maintenance and clean-up. And, of course, I do a good PEI sheet clean (esp. after applying goop) and Live-Z calibration whenever I start to have problems, then determine what else might be needed.

RE: need to re-coat both sides of two of my smooth PEI steel sheets

I've always said that Layerneer is not an alternative to keeping the build plate clean.

Cleaning the plate is also no alternative to a good Z calibration.

I'm also interested in an easy way to remove a damaged PEI sheet without a lot of Real Work.  It really sounds like the amount of work necessary to remove a damaged sheet is more expensive, time, effort, material-wise than just buying a new sheet.

RE: need to re-coat both sides of two of my smooth PEI steel sheets

Posted by: @jsw

[....] I'm also interested in an easy way to remove a damaged PEI sheet without a lot of Real Work.  It really sounds like the amount of work necessary to remove a damaged sheet is more expensive, time, effort, material-wise than just buying a new sheet.

It probably depends on how much do-it-yourself work you're accustomed to. The process isn't a lot of work, just a bit tedious (like sanding and paint prep). Next time, I'd use an aluminum pan and gloves and it shouldn't be so bad. I've read that Goo Gone is very effective at removing the glue. If it's faster, it might be a quick chore.

The problem is that the Prusa steel sheets seem very prone to corrosion once exposed to air. It's a lot of work to wind up with a crummy looking sheet, even if printing is not affected. My BuildTak and Printed Solid spring steel sheets, by contrast, don't show any corrosion months after PEI sheet application. The Printed Solid sheet with Buildtak's easy to remove PEI is a great combination. If those weren't an option, I'd just order a double-sided PEI sheet from Prusa. Unfortunately, they raised prices last year. They were a bargain at $19.

I have to admit to myself I've got plenty of sheets, and outside of the PPE push, have never had a real need to swap sheets rapidly for mass production. I really should just remove the damaged PEI and use the sheet for experiments rather than sink another $30 into it.

RE: need to re-coat both sides of two of my smooth PEI steel sheets

It sounds like you getting over adhesion with PETG.  I use a spray of Windex, wipe to spread, and allow it to dry on the plate.  This will reduce adhesion with PETG.  It had protected my plates.  

RE: need to re-coat both sides of two of my smooth PEI steel sheets

@cwbullet

Thanks.  My wife will never know where the windex went ....

RE: need to re-coat both sides of two of my smooth PEI steel sheets

Posted by: @dan-rogers

Thanks.  My wife will never know where the windex went ....

She'll be looking for the Dawn dish soap as well!

RE: need to re-coat both sides of two of my smooth PEI steel sheets

@dan-rogers

No issue.  My wife some time mutters things under her breath.  With the Windex and Dawn confiscation, I can only imagine what she is saying.  

RE: need to re-coat both sides of two of my smooth PEI steel sheets

@cynan

Music to my ears.  I've been saving my textured sheet for something.  Now I know what I have been saving it for.  I'm printing gads of fishing related stuff - swapping between two smooth plates so I can turn around production speed, and I'm down to only one usable side until my new smooth sheet gets here with the new PEI sheets so I can rework the ruined ones.  Been catching up on PLA projects while I wait - I'll try a tuna lure print tonight on the flex sheet.

RE: need to re-coat both sides of two of my smooth PEI steel sheets

The sheets are different thicknesses so remember to change sheet profile and redo your live Z. Also hot water, dish soap and scrub the textured sheet if you haven’t already.

RE: need to re-coat both sides of two of my smooth PEI steel sheets

On prusa website there should be a manual on how to do this.

RE: need to re-coat both sides of two of my smooth PEI steel sheets

Posted by: @peter-m-3

On prusa website there should be a manual on how to do this.

There is a guide online. As with any technique, there are variations and tricks.

I realized I had a few notes from a previous discussion on the topic of removing the adhesive. I haven't tried these yet, but they're worth considering:

• Mineral spirits are cheap and better than limonene.
• GooGone is primarily limonene plus petroleum-based solvents.
• 3M adhesive remover.

RE: need to re-coat both sides of two of my smooth PEI steel sheets

@bobstro

I've done this mess to myself twice with various media such as limonene and acetone and can only say - never again. The amount of work is not profitable for me. Instead, I prefer to buy an uncoated spring steel plate and coat it on one side with PEI or other materials such as Buildtak, CFK (FR4), Polyimid...

steel plate only

various print bed coatings

RE: need to re-coat both sides of two of my smooth PEI steel sheets

I guess it depends how much your own time is worth, spend half a day removing glue or buy a generic replacement steel sheet off Amazon for $20....

When I got my MK3S one of the first extras I got was a generic steel sheet and a sheet of PEI for one side of it.  I covered one side with painters tape, the other with PEI.  I had not had much luck in the past stopping ninjaflex from tearing up PEI sheets on my other printer so I use the painters tape side just for that, the PEI side I don't bother cleaning and covered with fingerprints PETG sticks just right, the original prusa sheet I do keep clean and use that for PLA.

RE: need to re-coat both sides of two of my smooth PEI steel sheets

@martys

Isn't that the truth.  My time is pretty valuable.  

RE: need to re-coat both sides of two of my smooth PEI steel sheets

Posted by: @cwbullet

Isn't that the truth.  My time is pretty valuable.  

Back when the double-sided smooth sheet was $19, no question. I ordered my 2nd without a thought. At $40 with shipping, they're now just expensive enough to give me pause. Replacing the PEI stickers sucked but it wasn't a weekend project or anything. Sort of like scoffing at others for paying someone $40 to change their motor oil, I suppose.

In reality, I know that if I order a replacement sheet with the PEI pre-applied, I can't bring myself to throw the old one away. So there it will sit, looking at me with those sorrowful eyes. The same thing that makes me work 4 hours to 3D print something I can get off Amazon works against logic. I wouldn't be printing with FFF if I valued my time that much. 

So the logical answer is obvious. Order another Printedsolid sheet with BuildTak PEI for $60 and 2 replacement Prusa PEI sheets for another $40 so I'll have 2 identical sheets just in case.