Bed Leveling not possible on my printer?

[LazMech]

Yea I'm printing with PLA. Thanks for the tip about cooling; there is evidence that it's having an effect. The two edges exposed to the cooling fan aren't great but they seem to be better than the other two edges that couldn't be cooled by the fan. Plus the printer is in a smaller room that gets really warm when I'm printing so that doesn't help the cooling. Although surely there is some effect from the convexity. Is PETG better with edges/overhangs?

[jimc]

i agree with jules. those fillets are going to come out kinda sloppy. its just the way it is because the first bunch of layers have perimeters just printing in the air. in a situation like this a 45deg chamfer always works best.

[Jules]

Yea I'm printing with PLA. Thanks for the tip about cooling; there is evidence that it's having an effect. The two edges exposed to the cooling fan aren't great but they seem to be better than the other two edges that couldn't be cooled by the fan. Plus the printer is in a smaller room that gets really warm when I'm printing so that doesn't help the cooling. Although surely there is some effect from the convexity. Is PETG better with edges/overhangs?

Yes, I've found that PETG is phenomenal on overhangs (as in - it keeps its shape very well - it's a very sticky filament.) No fan on PETG. But it does have to be dialed in much more carefully than PLA, and it prints much more slowly. ( In addition to having to deal with globbing issues from the aforementioned stickiness. You absolutely have to have the Z-stop height set correctly with PETG.)

If your print is sticking evenly to the bed, you don't need to fret too much about the convexity of the glass. (Grab a set of calipers and take a look at how small the difference in that gap actually is.) When you start to see paper thin first layers, or when part of the first layer will not stick at all, then it's gotten out of level and you need to adjust it. But as long as that first layer is fairly even, and it sticks uniformly, you're good.

[LazMech]

By the way, thanks a lot to everyone that replied; lots of valuable info. It's great having such an active community because there is just so much to learn and the more personal trial and error I can bypass the better. Looking forward to making something worthy of the Printed Object Showcase sub-forum.

[ednisley]

do you use S3D

Nope. Slic3r has a "First Layer Height" setting that's exactly the right hammer to start an object with absurdly thin upper layers, although I admit I haven't used it: uniform 0.20 to 0.25 mm layers suffice for my simple needs.

The bottom curve on that tub, as other have pointed out, just won't come out nicely. If the inside of the bottom surface need not be pretty, flip it upside down and see how bridging works. I'd add three support bars parallel to the long axis (1/4, 1/2, and 3/4 across the short axis) to help it out, because carving out an auto-generated support structure would be impossible.