Ok, contest deadline pressing I did the tank today. While the code is certainly chaos by now, I really love OpenSCAD: if you’re reasonably fast with typing, you can model quite fast, you have a very natural, easy way of accounting for certain constraints, and it’s fun. While of course a good OpenSCAD design should be fully parametric, allowing to easily scale my design to any wheel diameter, this is in reality not always easy to achieve, however. The tank I came up with still takes some modifications if you scale parameters by more than a bit, but hey, it’s my first machine!
Ok, so here’s the tank, fit with a mount to screw it onto a piece of wood which is supposed to be mounted on the back of your bike:
This takes some important things into consideration: the largest part of the tank should be only above the lowest bubble ring, to save on bubble fluid. And, to reduce spilling, I inserted bulkheads (which also serve as internal supports during printing), as well as a small wall in the upper part that also tries to reduce spilling. Here’s a cut to show how it looks inside:
Above the bulkhead walls you can see small holes supposed to let air circulate, so you don’t get problems with enclosed air when filling this with bubble fluid. Of course, a cap to close that refilling hole still has to be printed.
This has to be printed reversed, i.e. with the top down. It will still need support under that mount and probably in the middle of the half circle. There should be no support in the tank itself (except from above that refilling hole), as you won’t be able to remove it easily, and it won’t be needed because of the bulkhead walls — so I let the slicer generate support only from printbed. Although the first layer has a very large surface, I could get the first layers to print correctly until I turned on a raft; this is probably due to poor calibration of my printer.
This thing has now been printing for more than 4 hours, which is longer than my printer has done ever — it hasn’t even printed half of it, though. We’ll see. It’ll be a pain after this, when I’ll find out this doesn’t work …