Help with First Layer (Newb)
So I am a complete newb with this but I was able to put together the printer this weekend and print. I thought my first two prints were okay (the Prusa nameplate and Benchy) but my next two attempts came loose from the bed so now I am wondering if I messed up the calibration. I have included photos of the plate, Bench, and the recent calibration test. Any help is much appreciated! Thanks, Jeff 
RE:
Welcome. Your first result is better than those of many others, but I´d think you´re Z is still to high. I attach a 70x70x0.2mm square (i.e. a large-size first layer); slice it with the standard settings for your filament and print it in the middle of the bed.
Once the print starts, go to "Adjust Live Z" in the menu and lower it further in small increments (as low as in 10´s), watch the print get better. After better comes worse, it gets worse when the nozzle starts digging into the filament, then raise again in small increments back to perfect. The large square gives you ample time to test and to get a feeling. Too low is often identified first when the first cm or so of a return path is a bit rough and then only gets better over the remaining distance. Once you get really too low the full path will get uglier with "destroyed" lines.
For further details read (at least the first pages) of JeffJordan´s old, but golden thread.
Before you do, take the print sheet to the sink, grab some dish detergent without any re-greasing substances such as aloe vera, i.e. something whithout any skin-care stuff in it, take a sponge and warm water and give it a good rub, then dry with rubbing (sic!) it dry with some paper towel. Isopropyl is good for in-between, but after a couple of prints it´s much better to really wash the PEI sheet.
Cheers
Chris
I try to give answers to the best of my ability, but I am not a 3D printing pro by any means, and anything you do you do at your own risk. BTW: I have no food for…
RE: Help with First Layer (Newb)
Alternatively, I just noticed that our great moderator Joan has added updated versions of a large square, readily sliced for PLA, PET, as well as for ABS (which you do not want to use as a newbie). All are attached to JeffJordan´s first post in my link above.
I try to give answers to the best of my ability, but I am not a 3D printing pro by any means, and anything you do you do at your own risk. BTW: I have no food for…
RE: Help with First Layer (Newb)
This was super helpful, thank you! I was definitely able to find the right level for a better first print and just printed out the same piece that failed the first time and this time it worked perfectly. Thank you!