Notes vs 3d printers. 1. This guide is about making the mold-of-the-mold, the mold, and finally the final product. Its at least 3 steps before you get the fina

Notes vs 3d printers. 1. This guide is about making the mold-of-the-mold, the mold, and finally the final product. Its at least 3 steps before you get the final piece of plastic, rather than a single step process like 3d printing. 2. I hear that expensive software can help automate this process ("Design Product" -> "Auto build mold" -> "Auto build mold-of-mold"), but software is surprisingly expensive for hobbyists. Expect to be manually designing these molds and mold-of-molds unless you're willing to pay for some rather expensive software. That being said: "Rectangle -> Difference (product-shape)" is a good start. 3. The chief advantage of resin casting is the huge variety of paints and resins available. If you want a flexible material, get ShoreA 40 Urethanes. If you want a silvery material, buy silver pigments. If you want Red, you can buy red pigment. Compared to 3d printing, you have far more material selection (ShoreA soft materials, from grades 20 to 80, ShoreD harder materials from grades 20 to 80, etc. etc.). 4. There's also a "mass production" advantage. You can build multiple molds and "parallelize" the resin casting relatively cheaply. Once you have the "mold-of-the-mold", building 5 molds, and then using those 5x molds 10x each will be faster than waiting 50x iterations of your 3D Printer. Assuming your object is small enough to fit multiple molds inside your pressure chamber, of course. 5. If you are aiming at extruded ABS (aka: professional legos plastic), the mold-of-the-mold methodology is very similar (though made out of Aluminum and/or Steel, rather than Silicone like in this guide). There's still subtle differences between Aluminum molds vs Silicone Molds, but the similarities mean that you have a better idea of the final-final product with a silicone mold prototype. 6. EDIT: 3D printing is also compatible. If you wanted to make the molds or mold-of-molds out of 3d printers, you probably can do that. Its all just "shapes" after all. However, CNC Mills have far better accuracy than 3d Printers, so CNC Mills are just a better tool for this methodology. But if you don't wanna buy a CNC Mill to go through this process, feel free to play with the techniques listed here with a 3D Printer instead. -------- The biggest issue with #5 are the "shapes" that molds can make. Its much more restrictive than the "shapes" a 3d printer can make. If you design your shape to be 3d printed, it might be impossible to make a mold out of it that builds that shape. In contrast, if you actually go through the mold-of-a-mold / mold process as listed here, you innately are thinking about the final Aluminum/Steel die that Injection Molders will do. You have much lower chance of erroneously building a product that's impossible to die cast. IIRC, the main mistake is that silicone molds are flexible. If a corner gets stuck or something, you can just yank it harder and the plastic will come out. Aluminum/steel dies are very rigid. You can't just do that. So if you're "aiming to prototype an ABS Injection Mold / Steel die", you wanna design your mold to "cleanly lift" off a piece without anything getting stuck.