Thoughts on buying a Prusa i3 MK3  

RE: Thoughts on buying a Prusa i3 MK3

I'm using a standard Prusa PEI sheet for a year now and still don't have to flip it. (It's double sided, so you have actually two sheets). On my old MK2 I had to replace the sheet twice in a same period of time. 

Powder coated sheet behaves something different. There is less room for errors. I'm using mine if I need a part with nice looking face. Regular PEI sheet is my work horse. 

RE: Thoughts on buying a Prusa i3 MK3

Unless you print PETG, the smooth PEI works quite well.  I've used mine for over a year - and only one side. Still have a "new" side when the time comes.

RE: Thoughts on buying a Prusa i3 MK3

With the Prusa, longevity of the spring steel plate is about the last thing you should be concerned about.

Worst case, you buy a new $50 plate every few years. My smooth and textured show absolutely no signs of wear.

If the Prusa printer gives you the accuracy and reliability you are looking for - get it.

RE: Thoughts on buying a Prusa i3 MK3

With regard to printing PETG on the smooth PEI sheet, someone, somewhere on the Prusa forums recommended using window cleaning fluid (without vinegar) as a release agent. I started using that and haven't regretted it.  Until I tried it, I was having awful trouble getting PETG prints off the PEI sheet, and I was getting (cosmetic) witness marks where the parts had been. 

Similarly for  TPU, someone on the forums here recommended talcum powder as a release agent. I've been using a *very* small amount of finely ground chalk rubbed into the PEI bed before printing, taken from a puncture repair kit, and that's worked well.

You need to get the bed really clean after using either of the above if you want to go back to printing other filaments.

Apart from self inflicted problems of failing to clean the sheet properly, I've only had problems with ABS on the smooth PEI sheet, and that's usually solved by printing the part with a brim.

RE: Thoughts on buying a Prusa i3 MK3

The steel plate is fine and you won't have any issues.  I did manage to tear one up pretty good with some PETG that stuck to the PEI (I forgot to put a release agent on it and it tore some of the PEI up when popping the part off).  But that's the beauty of 2-sides.

Eventually, I did end up buying a replacement piece of PEI and fixed it.  Prusa has instructions on how to do it and it's pretty easy.  Basically peel the old piece off and put a new sheet of PEI on.  But I agree - replacements sheets (PEI and Powdercoat) are available for not much $$.  Just skip lunch a couple of days to pay for it.  

I also must admit that I've been using the powder-coated sheets ever since I could get my hands on one.  It's a nice surface texture and easy to use, once you have it dialed in.  

In a nutshell.....I wouldn't worry about the steel sheet wearing out.  Even if it does, you can get a replacement for about the cost of a spool or two of PLA.  

One thing I would suggest....if you have any technical skills at all, buy the "kit" and put it together yourself.  It makes maintenance/upgrades/etc MUCH easier.  There's plenty of guides on-line how to assemble it and you'll be 1000% better off with a basic understanding of what goes where and why.  Especially when you get your first filament jam.  You'll be able to disassemble the extruder, if needed.  

I've got a little Rubbermaid box where I keep all of the Prusa-extras, like screws, nuts, allen keys, etc.  

Anyhow...that's my $0.02.  It's not cheap, but in hindsight, I wish I had gotten the Prusa from the very beginning.  Right now, I've got a Monoprice paper-weight on the shelf that I haven't looked at since the day the Prusa showed up.  

RE: Thoughts on buying a Prusa i3 MK3

Get the MK3S with the smooth sheet and follow the manual. Works fantastic.