RE: Built the machine, but when I do the first layer calibration it does not stick to the bed
Well done! That looks great!
RE: Built the machine, but when I do the first layer calibration it does not stick to the bed
Prusa could save a lot of new users, myself included, a huge headache by just saying:
Powder sheet = PETG
Smooth sheet = PLA
RE: Built the machine, but when I do the first layer calibration it does not stick to the bed
@the-baron
Wash the sheet with Dawn, and it is fine.
RE: Built the machine, but when I do the first layer calibration it does not stick to the bed
@robert-rmm200
I've been 3d printing a long time, and just finished assembly of my MK3s... initial calibration went fine, but windex, IPA, multiple z adjusts and nothing. Simply wouldn't stick, even if I have the z too low. Gave it a super light scuff with 600 (can't tell I did anything) and washed with dish soap and victory. Looks like they just don't work out of the box without some prep. Whew! Now to figure out the filament autoload not working.
RE: Built the machine, but when I do the first layer calibration it does not stick to the bed
Hi David,
The Filament Sensor is a bit finnicky on the Mk3, some you can adjust to work, others need a modification to work, there is a 0.5mm spacer on Thingiverse that some folk find useful...
I have soldered a 5volt LED between the 5volt sensor pin and the middle pin on the sensor, and this gives me an immediate confirmation of switching, without having to dial up an LCD Menu option. 
Here is a picture with the cover removed for clarity.
the top picture is the Mk3s with MMU2 tower,
the bottom picture is the same mod on the Mk3s without MMU2s
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Built the machine, but when I do the first layer calibration it does not stick to the bed
@the-baron
Wash the sheet with Dawn, and it is fine.
That seems to be adequate for some people but I have seen numerous reports of people, like me, who didn't see improvement after multiple washings. On other forums I have seen people bag it altogether and order an aftermarket powdercoated sheet that worked without issues.
A light buffing with Scotch Bright was the only thing that helped after multiple days of frustration. Seems to work equally well now for PLA and PET, running the PLA 10 degrees hotter (I started with 20 and backed it down);
RE: Built the machine, but when I do the first layer calibration it does not stick to the bed
This article also mentions denatured alcohol as an option: https://help.prusa3d.com/article/6Gtws6Yqjg-pei-print-surface-preparation
RE: Built the machine, but when I do the first layer calibration it does not stick to the bed
A bizarre turn of events!
After a couple of days of successful printing my prints suddenly began detaching again - both PLA and PETG. I ordered a standard steel sheet, but in the meantime I have Christmas presents to make.
A Prusa tech suggested denatured alcohol. Didn't work. I washed with Dawn and hot water a couple of times, as before, and buffed the surface again lightly with a Scotch Brite pad. I'm printing PLA right now and it seems to be working. At this point I'm not too concerned about damaging the textured surface, I just need to buy some time until the new sheet arrives.
RE: Built the machine, but when I do the first layer calibration it does not stick to the bed
@kellan_hatch
Is it possible that your PETG has been outside the bag and collected moisture from the air? I’m not sure if this could be the cause, but suspect it happened to me.
RE: Built the machine, but when I do the first layer calibration it does not stick to the bed
@kellan_hatch
Someone suggested soaking the sheet in 99% Isopropyl alcohol. Leave it soak for about half of an hour.
Remove it, dry it do not touch the surface. Supposedly that works, I am still having problems with prints adhering to the bed and I know my first layer is good. Going to have to add brims to everything.