3 ms·

You're welcome. I just realized there is a bit of nuance missing from my comment. The unattractiveness of casting diminishes even if you only want one of a thin

You're welcome. I just realized there is a bit of nuance missing from my comment. The unattractiveness of casting diminishes even if you only want one of a thing if it is the case that you will want many things rather than only one thing ever. Many of the videos on the subject seem to be of experienced makers creating many different unique objects. This does of course allow you to amortize the equipment costs across many projects, just as you can for machine tools, and the optional equipment I mentioned (whether purchased or DIY) becomes much more approachable. Still, it is really hard to beat vacuum forming for approachability in making a one off: The only equipment you don't have laying around can be made with a few chunks of wood. If you have a small oven (even a toaster oven) that only limits the size of your parts. If you have a vacuum cleaner with crappy suction, that just means you can only form thin sheets. BTW, all these techniques combine. In the case of resin casting, I mentioned that you really need to have made a one-off in order to create the silicone molds. In fact, I have in the past vacuum formed a blank shape (this was before 3D printing was a thing), sanded or machined it to more precise tolerances, added details (dedents, screw posts or holes, flanges, ribs, ridges, textures, etc.) and then used silicone molds and resin casting to make duplicates. Sometimes you actually do need several identical parts in order to just make one object...

kragen 5y ago
Yes! Today I bought 20 identical poorly-injection-molded T-fittings for aquarium air hose, and I was thinking about your comments. It occurred to me that the existence of injection molding strongly favors designs that have several instances of the same part, like four identical wheels or 15 identical spring clips. In some cases I think there are materials that are a lot easier to shape to make a mold pattern than whatever you're going to make your final part out of. Wood is the traditional choice, except that wax is the even more traditional choice, and clay, styrofoam, foamed waterglass, and pumice also come to mind. I guess in theory polycaprolactone might work, too, and as you say, poly(lactic acid) is a popular modern choice, sometimes painted or sanded to smooth out the print lines. And I've been wondering if it's feasible to strengthen aluminum foil by spray-painting or cathodic mineral deposition in order to make such one-off items, because aluminum foil is very easy to form, usually too easy. Lots of stuff to try!

kragen 5y ago

Yes! Today I bought 20 identical poorly-injection-molded T-fittings for aquarium air hose, and I was thinking about your comments. It occurred to me that the existence of injection molding strongly favors designs that have several instances of the same part, like four identical wheels or 15 identical spring clips. In some cases I think there are materials that are a lot easier to shape to make a mold pattern than whatever you're going to make your final part out of. Wood is the traditional choice, except that wax is the even more traditional choice, and clay, styrofoam, foamed waterglass, and pumice also come to mind. I guess in theory polycaprolactone might work, too, and as you say, poly(lactic acid) is a popular modern choice, sometimes painted or sanded to smooth out the print lines. And I've been wondering if it's feasible to strengthen aluminum foil by spray-painting or cathodic mineral deposition in order to make such one-off items, because aluminum foil is very easy to form, usually too easy. Lots of stuff to try!