Mine have been trading me well. Just the one piece (the corner lock) but it’s because the raft was flawed under the print so it bonded too hard with the print itself. Otherwise all rafts have been magically peeling off for me.
I think I am one of the few who are using rafts all the time. I have just had so much success with it that I don’t want to ruin a good thing. Every once in a while I will try something without a raft and it will fail of the bottom will be messed up in some way. So I find i waste less plastic by just using my raft.
Yes, some plastics are difficult to remove the item from the raft. In Cura there is a setting called air gap. It is the gap distance between the raft and the object being printed. For ABS and HIPS I make that very small like 0.05 mm. For PLA I keep it 0.35 mm for PETG I use 0.5 mm. With these settings it is usually really easy to remove the raft from the part.
Well, it let go after about 2mm of print - but only one side (right side) so just for fun I’m going to pull the yellow, load the new white and run the same file again, same everything. See what happens.
White PLA. All seems right with the world but dammit…I tweaked the z endstop by a 1/4 turn before letting it rip. I should have left it. One variable at a time…
I have a video of the first layer and despite a little booger (not sure what it was) it looks great and markedly different than the yellow. I’ll post that when I get back to my desk.
On my personal printers, the only time I used a raft was with the test print that came with the printer. I print on glass (after fighting with blue tape either not sticking to the print at all, or bonding with it at the molecular level with very little in between) with hair spray. I level the bed manually (no autolevel). I level with everything heated to printing temperature and set the bed so there is barely a hair width gap between the bed and nozzle. First layer is the same height and line width as the rest of the print, but 40% speed. Great first layers and great adhesion with no need for rafts or other wastes of filament.
I do occasionally use rafts on the printer at work. I haven’t added glass yet and the buildtak surface is pretty chewed up. It’s dual extrusion so I’ll use PLA for the raft and ABS for the print, or vice versa, so the part and raft separate easily. But I don’t actually use that printer very often so tend to forget about it when talking about using rafts.
Back to the original topic… different rolls of filament can behave differently. Different colors of even the same brand may require different temperatures or first layer settings.
I’ve used rafts only one time in my life, because it was a complicated print who needed weird supports. Other that that, never.
PLA doesn’t need heat for small prints, but for large prints it helps greatly to reduce warpage (it’s not entirely failproof though, you’ll still need to apply the glue stick nicely). It also helps later to detach the print, usually after I get my print finished, I remove the glass and put it directly under a stream of cold water. The print then just pops up by itself. I have several glass plates so I can continue printing during that time, and let the other plate to dry.
Just find some piece of glass or a mirror and replace your weird bed material with it, it’s real easy, super cheap, allows you to continuously print and basically never fails. I see only advantages, except maybe for some exotic materials who won’t stick well to it. But for 99% of applications this works brilliantly.
And stop procrastinating with your BL touch! I had the time to build entirely a new printer this week and you didn’t even install this thing yet. Procrastinating is just not what we do here at V1Engineering! XD
Bull corn! 
I don’t do ANYTHING without MUCH procrastination! Procrastination was the BEST TOOL in my toolbox when I worked in CAD/computer support… it was amazing the number of problems had fixed themselves by the time I got there
BTW before I got my Prusa I3 MK2S with PEI bed… the glass with cheap Aquanet hairspray worked a champ with my FolgerTech 2020 I3… 
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PEI on Aluminum is far from a weird bed material…
Still chugging along. There’s a nice new corner lock for me if all the rest fails 
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Ok, but I still fail to see the advantage over just a regular glass plate.
-You can remove a glass plate, put another one and print, which leads to almost no time loss between prints
-Glass plate is cheaper, from what I’ve seen here in china at least,
-Glass acts like a heat damper/capacitor, so it helps keeping temperature consistency over the heat bed
-You don’t need to glue it to your bed, so the removal process is super easy in case you broke it
-It is usually flatter than the aluminum plate itself, so it helps with planeity a little
-Glass+glue stick works fine regarding adhesion
Is there something I’m missing? I’m genuinely intrigued as to why bother with this stuff.
I’m definitely not saying glass isn’t a good solution, just that PEI is too.
I used glass for a while and I liked it, but the inductive sensor didn’t work through it. The other reason I didn’t like it is I am convinced it doesn’t heat up much in time for the first print. The aluminum bed gets to 55C, and the top of the glass is still warming up when it starts to print. The other annoying thing about was I was using binder clips to attach it, and I kept crashing the nozzle into them.
I’ve been very impressed with both my pieces of PEI, although they do act differently. I’ve been adjusting things so it’s just barely sticking. Most of the time, I can just pop the part off without a tool and I use a finger nail to pull up the skirt. If you don’t smush it too hard, it comes off much easier when it’s cold than hot. I haven’t taken either of them off. I’ve probably been printing on the first one for about a year. I don’t often clean the bed, and I haven’t ever done a deep clean with the magic eraser and windex. I am not constantly printing though. If I ever need a part to really stick, I can bump the temp by 10C and babystep the Z down a bit and I’ll need to really work to get it off. I’ve used the upside down can of air a few times.
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I have been reading online that spraying a little IPA around the edges of the printed part will cause it to pop loose and then as you wipe it off it acts to clean the PEI.
I have not tried this my self but they seem to say it works magic. I believe There is a scientific name for the affect where the liquid sucks in under the piece and causes it to release.
I assume the same principle applies to washing the glass bed with water that causes the parts to release. Very interesting.
IPA? Around these parts that’s a cold beer! Not saysing that it might not work but there’s other places I think a bit of beer would be suitable for - like in my belly!
I now have the second LCD case at the very least here. I tugged on the parts and they are STUCK. I’ll let you know what mythical weaponry was required to pop it and how the raft came off. I was looking at the photos and saw the scaling in the top layer of the raft. Or that’s what I call it anyway. That irregularity is the source of the raft not pulling off the part cleanly in my experience so far.
[attachment file=77359]
[attachment file=77360]
And I will eventually get around to getting the BL Touch installed - I promise. And trying all of these things I’ve been learning.
I guess the root of this thread (for me anyway) is when switching to a new filament, what are the things you need to fiddle with to try to dial it in? I’m surmising the folllowing (and that could be the first time I’ve ever used that word - hope I got it right 
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first layer height (the smoosh)
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first layer speed and temps
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extrusion multiplier
this, assuming all other gremlins are neutralized (bed leveling, temp control, surface cleanliness/prep etc).
I’m sure I missed one or two things.
That’s right. I don’t think I’ve adjusted the z height for different filaments, but if aomething is having trouble sticking, I might. It’s mostly temperature for me.
I do hear a lot of good things about PEI. I wouldn’t mind giving it a try if I got some for free. But glass & Aqua Net is working too good for me to spend money to experiment on something else.
Manual leveling is so quick and easy and so seldom even needed that I haven’t felt the need to install any kind of auto-leveling system.
What materials are you using that are that sensitive to bed temperature? I seldom use anything but PLA or TPU and neither are that sensitive to bed temperature. I bought some Nylon but haven’t had time to mess with it. I’ve printed a little PETG but didn’t have any issues due to bed temp. The only thing I’ve printed with much of outside of that is Algix Dura and Alga filaments and didn’t have any issues either.
My humble opinion is that binder clips are the wrong way to attach glass to the bed. The 0.5mm thick silicone thermal pads is the best way. If the aluminum heated bed is warped (as aluminum tends to be when heated), binder clips can make the glass flex defeating one of the purposes of using glass - its flatness. Plus there’s the annoying issue you mentioned. The thermal pads allows the glass to “float” over the warping aluminum bed and stay flat. The pads securely hold the bed from lateral movement, but it’s super easy to pick the glass up for part removal (set it in the freezer for a few seconds), cleaning, re-application of hair spray without getting it all of the rest of the printer, and set it back in place.
– first layer height (the smoosh)
My first layer advice does not apply to using rafts. I hate them and don’t use them. So this is for printing without a raft. And this is just my opinions and advice and how I do it. There are many, many “right” ways to do it. If your print is successful, you did it right! With that in mind… First, level the bed pretty tight. Not so the nozzle is touching the bed, but so that it’s only barely not touching it. The gap should be much less than the thickness of a piece of paper.
The “setting the gap with a piece of paper” comes from the dark early days when people were still figuring things out and guessing at a lot of it and sharing “what works for me” eventually became “this is how you have to do it because that’s how everyone before me did it.” The initial method was to level the bed with everything cold, set the gap so the piece of paper was just barely being grabbed by the nozzle. When everything heated up, that gap would close from the thermal expansion of the nozzle and bed. So Z height of 0 was actually ON the bed, at 0mm. Then you had to use really thick initial layer heights to compensate for warped beds and overlap seams in tape and so forth, but at least a first layer height of 0.3mm was actually at 0.3mm. Then people started realizing they weren’t such fragile creatures and could level their bed without burning themselves and wouldn’t have to make a guess at how much thermal expansion there would be and started leveling their beds with everything heated. But the “set the gap with a piece of paper” advice hung around as did “use a really high 1st layer” and “use a raft” and other things that were outdated. Leveling the bed with everything heated and setting the gap so the nozzle barely grabs the paper, you’re setting Z0 at 0.1mm above the bed. Your real initial layer height will be the set hight PLUS that gap. So now we have to compensate by increasing the extrusion width and other tricks.
Forget all of that. Level hot. Set the gap so there barely is a gap. You can use a feeler gauge, but I just use paper. It’s cheap and easy and there’s always a piece nearby. Since I use glass, a personal trick I use is to listen for the tink sound of the nozzle hitting the glass as the paper slides out from between them. Once the slightest most minute little nudge of the leveling screw (use big thumb screws for easier precise control) makes that tink go away, I have it right. Now Z0 is actually at 0mm from the bed. The initial layer height set in your slicer is the real layer height. Set the initial layer height to 100% or to the same height as the rest of the layers depending on how it is represented in your chosen slicer. The first layer should “smoosh” on the bed but not too much. Use a skirt of multiple lines and watch as it’s being laid down. There should be no gap between the lines, but it should also be a smooth top. If there is a gap between the lines, the nozzle is too far from the bed. If plastic is rising back up between the lines, it’s too close. The filament is coming out of the nozzle in the shape of a cylinder. Think of a bunch of pencils side-by-side on a desk. Because of their shape, even though they are touching each other, there’s a gap under them and they’re actually not making a lot of surface contact with the desk (imagine perfectly round pencils). Imagine being able to smoosh them down a little so they spread out and fill the gaps between them giving maximum surface contact, but not smooshed so much that you’re overfilling the gap and it’s squeezing back up. That’s what you want the filament to do on the first layer.
– first layer speed and temps
You don’t have to print the first layer super slow. While I do print the first layer at 50% speed, since my print speeds are 70mm/s and faster, my first layer speed is still faster than some people’s max print speed. My reason for slowing it down is just to watch for any problems starting out. I don’t do anything special on the first layer as far as temperatures go, but I do for cooling. I leave the fan off for the first layer, then turn it on for the second layer.
– extrusion multiplier
The first thing you should do with every roll is use your calipers and measure the diameter of the filament. Measure several spots along at least several feet of filament. Use that info to set the filament diameter in your slicer. And as you’re printing, randomly take a few sample measurements, especially if you notice a change in extrusion. These days, most filament is pretty consistent throughout the spool, but different spools may be inconsistent with each other. For example, one spool may consistently be 1.73mm to 1.77mm, but the next spool may consistently be between 1.71mm and 1.75mm. I have found Hatchbox to be of high quality and consistency, but other brands not so much. You may also need to calibrate your extruder steps. I’m going to take a shortcut here and refer you to this video which goes though the fundamentals of calibrating extruder steps, extrusion multiplier, temperature and speed settings, etc.
Keep in mind that there are a million different ways to do things and few of them are “wrong”. Someone else may give you advice that is completely different from my advice. And that is OK. We could both be right. You’ll learn most from doing. Take all the advice, try different things, experiment, and learn what works for you.
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w.r.t. glass. That’s totally fine. I think you’re right on all of that. I could have been experiencing troubles for other reasons, and just blamed the bed leveling. I can print a lot larger things now than I could when I was using glass, but I’m also much more knowledgeable.
I used the silicone things, and I think it was even colder on my bed.
I will never use hair spray. I hate the smell of it. No way I’m going to dust my whole workshop with that stuff. That’s my $0.02. Blue tape and glue stick have both worked fine for me.
Yep, it’s all about finding what works for you. Glue stick, blue painters tape, kapton tape, hair spray, glass, PEI, buildtak… there are so many “right” ways.
Yet again this community leaves me in awe with the freely giving of time help a guy out…