Intro: Recycle Project - Bullet Casing Coins
This Project was a part of a school recycling project for my engineering class. The goal of this project is to take something that is readily available that is something that is normally thrown away or recycled.
One resource I was able to find were bullet casings. Surfing the web for possible recycle projects, I came a crossed a video ofa youtuber who was casting bullet casings. Without prior knowledge, I decided to take on the project. I seeking help from my metals / welding teacher, he reluctantly agreed to teach me how to melt and cast the brass into a pattern.
Make sure you take proper safety precautions for you will be exposed to extreme heat and workshop tools.
- Brass Bullet Casings
- 3D Printer Filament
- Brass Flux
- Brass Polishing Compound
- Oil Tempered Sand
- Metal Smeltery
- 3D Printer (Taz 6)
- Sand Paper (Multiple Grits)
- Wire Brush Wheel
- Polishing Wheel
- Hack Saw
- Variety of Files
- Ingot Mold
- Casting Pattern Frame
- Solid Works
Step 1: Create Your Casting Pattern
For this project I used a 3D model as my pattern in order to achieve higher details in my casting. To create these models I used SOLIDWORKS. The two coins are approximately Ø 3.5" for each coin with a depth of 0.5". With metal casting, you do not need to used 3D modeling to create your pattern template. Other methods use High Density Foam, Wax, etc.
After I created the models, I exported the SOLIDWORKS files to an .STL file. Next I then placed the two models side by side and queued them to be printed. After completion of the printing, I then sanded the bases off using sandpaper / a belt sander.
Step 2: Stamping the Patterns
I used oil tempered sand. By doing so, I was able to achieve a finer more detailed cast. To help release the pattern from your mold, I used baby powder so it wont stick to the sand.
Next, create your sprues and risers. The sprue is where you pour your molten metal into the mold and the riser is where the molten metal raises, indicating your cast is full. Then place the two halves together
Step 3: Time to Smelt!
After ensuring there were no live rounds in crucible, I placed the casings and the crucible into the smeltery and turned up the heat. After approximately 40 minutes, the brass casings started to melt down into a pool of liquid brass. Afterwards, I poured brass flux into the crucible and then ensure it was mixed in the brass completely.
Step 4: Doing a "Pour" Job
Next, take the crucible out of the smeltery and begin pouring. In this situation, one person is the pourer, controlling the pace of the pour. The other person is in charge of controlling where the pour is located. It is important that the pour remains at a constant pace the entire time, otherwise the molten metal may cool faster than the pour resulting in flaws in the cast.
Step 5: Removing the Molds
Separate the two halves and dig up your molds. If the material you used to cast is re-usable, then put it in a bin for another time.
Step 6: Cleaning Them Up
After removal from the molds, cut off the sprues and risers from your cast and take a wire brush to remove any excess material left on your mold. I used a hack saw and a variety of files to clean up the spots where the sprues and risers were. Next, I took my Dremel sanded the top of the "CTA" coin with a fine grit sanding wheel. Finally I took a brass polishing compound and my polishing wheel and shined up the top of the coin.
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