[Florian] has a few arcade games and MAME machines, and recently he’s been trying to embed objects in those hard plastic spheres on the end of joysticks. A common suggestion is to 3D print some molds, but even though that’s a great idea in theory the reality is much different: you’re going to get layer lines on the casting, and a mirror finish is impossible.
No, a silicone mold is the way to do this, but here 3D printing can be used to create the mold for the silicone. Instead of a few pieces of hot glued cardboard or a styrofoam cup, [Florian] is 3D printing a a container to hold the liquid silicone around the master part.
After printing a two-piece part to hold both halves of a silicon mold, [Florian] put the master part in, filled it up with silicone, and took everything apart. There were minimal seam lines, but the end result looks great.
In addition to making a 3D printed mold container, [Florian] is also experimenting with putting 3D printed parts inside these joystick balls. The first experiment was a small 3D printed barrel emblazoned with the Donkey Kong logo. This turned out great, but there’s a fair bit of refraction that blows out all the proportions. Further experiments will include a Pac-Man, a skull, and a rose, to be completed whenever [Florian] gets a vacuum chamber.
Some people see 3D printers as expensive and slow devices for replicating bracelets, whistles, and Yoda heads. Until the world transitions to a plastic octopus-based economy, those of us with 3D printers will have to find something useful for these tools. Bayesian Empiritheurgy out of Halifax, Nova Scotia wanted to do something useful with their 3D printer for the large-scale, distributed hackerspace competition, The Deconstruction. They ended up using their printer to make molds for a paper mache violin, and ended up being fairly successful at it.
The basic idea behind their paper mache violin was to create a plastic mold for exactly half a violin body. This block was covered in newspaper drenched in wheat paste. Once the paste was dry, the violin half was pulled off the mold and another half was created. These were stitched and glued together, resulting in a violin body.
The bridge, tailpiece, tuners, and fingerboard were 3D pprinted and held together with epoxy. The epoxy flexed a lot, so every time a string was tuned it threw out the tuning of the other three strings. In the video after the break, you can check out the paper mache and plastic violin being played. It’s not much for the eyes or ears, but everyone had fun, and the team completed the proof of concept for a fiberglass or carbon fiber violin we’d suggest they try next.
Continue reading “Making a violin mold with a 3D printer”
The folks at SC-3000 survivors have been working on a cartridge capable of storing dozens of games for the ancient Sega SC-3000 computer. The PCB works beautifully, but making a case for their cartridge left them with few options. They could use a 3D printer or simply collect a whole bunch of used cartridge cases, but making their own mold for a cartridge case was the best solution.
To create the mold for their multicart enclosure, the SC-3000 survivors first took an old, used case and made a silicone mold. While the first attempt at mold making was encouraging, several problems began to crop up due to the lack of vent holes and wiggling the mold before the resin had set. Before long, a proper technique to make resin casts was developed: use lots of resin, and don’t apply pressure or rubber bands to a curing mold.
We’re always impressed by what can be done with a few sheets of plastic, some Bondo, and the inordinate amounts of patience and sandpaper we see with other case mods and enclosure builds. the SC-3000 survivors put together an enclosure that rivals any Bondo build, and we’re happy they put out this tutorial.
Need fifty copies of that 3D printed whirligig you’re so proud of? It might be faster to just cast copies by using the 3D printed model to make a mold. [Micah] found himself in this situation and managed to cast one copy every 10-12 minutes using the mold seen above.
With the object in hand, you need to find a container which will fit the mold without too much waste. The bottom half of the mold is then filled with modeling clay, a few uniquely shaped objects to act as keys, and the model itself. After getting a good coating of release agent the rest of the mold is filled with a silicone rubber product which is sold for mold making. This creates one half of the mold. After it cures the clay and key objects are removed, everything is sprayed with the release agent, and the other half of the mold is poured.
Now your 3D object can be copied by pouring two-part resins in the to shiny new mold.