• 3 Posts
  • 12 Comments
Joined 2 years ago
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Cake day: July 21st, 2023

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  • Thanks!

    This is pretty darn ambitious for a starter project. I say this as someone who is trying to get some fancy new 3D printable tomato cages going before the plants get tall and dangerous and I’ve been doing this for a while.

    Yeah, I realize it is ambitious, but my inexperience is perhaps making me think this will be doable from the get-go when it’s really not? We’ll see… I have a limited time before it no longer makes much sense to pursue this this year, so at some point I will need to cut my losses if I haven’t gotten anywhere.

    So you really probably want to de-complicate this, either by only making planters that are sized for the printer or finding a existing planter that’s the right size but not self-watering and designing just the self-watering part. You’ll probably learn a lot about the right way to do one this year and then next year you can attack the next generation of the planters.

    The design itself will be quite uncomplicated: a bottom container which will hold the water, and then some plates that will hold the soil, supported by the cups that will be submersed into the water that will be packed with soil and perforated to allow absorption. I was planning on lining these plates with some soil fabric so I could keep them loose, only with holes cut out for the cups. The reservoir will be filled through a PVC-pipe that leads from the top and down to the reservoir. I will then build this in with wooden panels (loose, as I otherwise would be unable to get the whole thing inside the shelf where these will go).

    One of my big problems last year was finding anything of the right dimensions already existing. They will need to fit inside the shelf.

    The problem with printing in pieces is that you are going to have to make sure that the joints are strong enough for the weight of the soil. This is why using a ready-made outer container might help. In the same way, what you really want is something finger-ish or jigsaw-ish so that the pieces align themselves more easily and interlock.

    The soil container will have a quite broad base compared to the height. The plates that will hold up the soil will be supported by these cups as described above, and I can make these cups as broad as I need. Are PLA or PETG not particularly strong?

    How do people achieve these interlocking patterns - standard tools in the software, plugins or do you do this manually?

    You will probably want a fatter nozzle, otherwise this is going to take forever to print.

    Oh, good point I didn’t think about, and adding this to be research list. I guess it is delivered with a 0.6mm nozzle.

    PETG seems to have worked fairly well for me for outdoor stuff? Coating or paint or whatnot is handy. You might want to look at the epoxy family? If you can print on the balcony, you might consider ASA which is totally fine for outdoor use with no paint.

    Cheers! Two suggestions for PETG, so I should probably order some filament already! And adding epoxy to my research list, thanks :) Printing on the balcony will unfortunately not be an option for now.

    FreeCAD is a bit of a learning curve? The thing that FreeCAD would make easier is a parametric model, where you say that you want a 400 x 400 x 300 planter. Except that if you are really serious about making large self-watering planters that are parametric, you are going to end up wanting to write code to make it all happen, which either means the Python in FreeCAD, the Python in Blender, or maybe just use OpenSCAD.

    I will need to look into parametric modelling it seems. Python I am very familiar with, so making use of that in modelling would in any case be a good skill to acquire. My instinct was just to add a mesh in Blender and resize to my desired dimensions and that would be good enough. My tolerance for the outer parts here is quite high, but for the joints I would want higher precision. OpenSCAD I have not heard about, so I will check out that.

    The dimensions of the planter would be 120x40x40 cm ish (based on eyesight from where I am sitting).

    One avenue, which is also too big of an ask for this season, is making a multi-part model to cast the large pieces in concrete.

    Oh, interesting - that is far from anything I’ve considered. But yeah, not quite something I would be ready to tackle for this season.

    Another avenue would be to just design around the outside being wood and the 3D printed parts being brackets and jigs and connectors and the self-watering bits.

    It is not that far from what I am going for actually, but the self-watering parts is basically a water reservoir, so it would need to be a water-tight container. Had I only been able to find boxes of proper dimensions where I live, I would not even consider trying to 3D-print this. But they are either too tall, too deep or not long enough.


  • Ambitious early project.

    Hehe yeah, I would have gone with something else as my first project had it not been for the fact that I want these planters soon. I had hoped to get the printer earlier, but after asking for advice on my printer purchase here end of last year, I got a compelling advice to at least wait for first reviews before deciding, and by that time Prusa had a backlog on orders.

    I’d probably go with petg.

    Due it to being outdoors?

    There are plenty of good tutorials / suggestions for general water tightness with regards to slicer settings. Water tight joints will be tricky. Consider sanding and then torching them. I’ve had good results with clearcoat spray after sanding pla. May work with petg too.

    Nice, will check that out in more details! Are clearcoats typically non-toxic? Torching the joints sounds like a good idea - what would you typically use for that, a standard crème brûlée burner? I plan on making smaller prototypes to test out any concepts out before making a huge one.

    Curious why you didn’t go with xl for this? Cost?

    Cost is one major reason, the Core One was at the top-end of my budget, but it is not the only one. The Core One otherwise fit my requirements very well, and the XL would also not be able to print this in one go. This is by far the largest pieces I have planned on printing, and all the other prints on my “todo”-list will fit in it just fine. I wanted one with an enclosure, and I didn’t like the look of the XL with an enclosure, as it will be quite visible where it will be placed, and I’m the kind of person who would care. And I also believe the footprint of the XL is larger? In that case, I am not so sure if it would even fit on the designated space for it.