Hi Hive13 family, and happy post-holidays to you all!
For years there have been whispers of people’s desires to be able to cast metal at Hive13. To that end, I have done the research to develop a list of what equipment would be required to establish a casting station at the hive.
There are many, many different methods and techniques for casting metal. The setup I propose we start out with is a simple investment casting setup, with a torch for melting small volumes of metal. This setup is limited to melting about 4 oz. of metal at a time, so the maximum size of parts that can be cast are limited, however, the quality of the castings you get are extremely good, suitable for things like Jewelry with fine engraved details and prongs for stone setting. The setup would also be suitable for casting small mechanical parts for things like RC Model Engines, Drone parts, etc. It could also be used to cast metal tabletop minis and other toy-like items.
The process required to make a part by this process starts with a wax model. The wax model can be carved by hand, machined on a CNC mill (the Roland would be perfect), cast in a silicone mold, or even 3D printed with a wax casting 3D printer filament or resin.
The wax model is then attached to a wax sprue, inserted in a metal casting flask, and a ceramic slurry material, called investment, is poured around it. The ceramic cures to solid around the wax, leaving the wax model and sprue embedded in the investment.
The investment mold and model are then placed in a kiln (which we already have in the glass area) to “burn out” the wax from the investment. This process melts and burns off the wax, and it cures and preheats the ceramic investment making it ready for pouring metal into the cavity.
Once the burnout is done, and the investment is ready, the metal is then heated with an small hand held oxygen/propane torch in a crucible. This process can be used for melting gold, silver, bronze, silicon bronze, white metal, aluminum, and many other precious metals and engineered metals. Up to about 4 oz. of metal can be melted and cast at a time using this method.
Once the metal is molten and ready for pouring, the investment mold is removed from the kiln and placed on a vacuum machine. the investment material is porous, so the vacuum allows air to be sucked out of the mold, pulling the molten metal deep into the mold cavities, fast enough to prevent it solidifying before the mold is filled. The metal is poured from the crucible into the mold with the vacuum running.
After the pour is complete, the vacuum machine is turned off, the metal allowed to cool enough to solidify, and then the investment flask and casting are quenched in water. The water dissolves the investment, revealing the finished casting. The part can then be removed from the sprue with a jeweler’s saw, and cleaned up with files and emery paper, and polished if desired. Mechanical parts can also be machined on the mills and lathe in the machine shop to ensure accurate functional surfaces if needed for the application.
Here is a good video that steps through the majority of the process: https://www.youtube.com/watch?v=Dbj41zl57aw
I have put together a list of all the equipment we would need to get started with this, sufficiently to make it enjoyable, and with enough consumables to allow members to learn the process and get certified. the full list can be viewed here: https://docs.google.com/spreadsheets/d/1zVvEHwLEBngNbHcibRAZBm_dvLo1fvwxKBkMSeI5oQo/edit?usp=sharing
On that list, the largest items are the Vacuum Investing & Casting Machine, and the torch (w/ associated plumbing and tips). It’s worth noting that both those items can be used for much more than this investment casting. The vacuum table is also suitable for degassing resins (epoxy, silicone, etc.), stabilizing wood, and other activities requiring a vacuum chamber. The torch is also extremely useful for fine detail work in the glass area, a perfect companion for the big Carlisle CC bench torch we have, and doing glass assembly work. The torch would also be suitable for many soldering and brazing tasks, like jewelry assembly soldering, ring resizing soldering, making brazed carbide mill and lathe tools for the machine shop, hardening and tempering tool steel for custom form tools, or brazing parts for things like model engines/boilers, etc.
The total cost for the equipment and starting stock of consumables, including wax stock, investment, and a stock of bronze casting grain, comes to about $2600. In the spirit of the holidays (and avoiding spending Hive13’s money till we get AC installed), I am hoping we can get enough members interested in chipping in donations to cover this purchase.
I’ll start off by committing to donating $700 (enough to cover the torch and associated equipment) toward this. Please, if you are interested in getting this type of equipment set up at Hive13, consider contributing to this purchase. My plan is to hold off on collecting any money till we know if we have enough people interested to cover the whole cost. If you are interested in contributing, feel free to post here with what you are willing to contribute, or if you would like to remain anonymous, send me a private message on slack or email me at firstname.lastname@example.org.
Thanks to every one of you for making Hive13 an amazing place! As hard as this year has been for everyone, our maker community has truly had an impressive and wonderful year. It’s so nice being in the new place, and Hive13 is a genuine joy of a place to make things, thanks to all of your efforts!
Hive13 Glass & Metal Work Warden