Ghostbusters was so much fun. SO MUCH. I highly recommend if you haven't seen it yet.
This isn't designed as a 100% accurate replica of the movie prop, but rather a quick and cheap build for fun and enjoyment. So... have fun and enjoy! :)
1 - 1.5" split key ring
1 - 2" screw (I used pan head phillips #10 sheet metal screws)
1 - 18" necklace chain
1 - 0.25" jump ring
Small sheet of aluminum (0.019" thickness)
Soldering iron/solder OR super glue
Sandpaper (120 and 500 grit)
Rotary tool with cutting wheel attachment
Optional: Helping hands tool
Fabricating the "U"
Note: Alternatively, you can probably find pre-made "U" shapes for jewelry or make a faux metal "U" out of polymer clay.
Draw or print "U" stencil. I made the included stencil from what I could remember from the movie and comparing to images I found online. Feel free to use or modify.
Cut out the "U" and tape the stencil to the aluminum sheet. Trace out the design with a black marker (don't worry about permanence, you'll sand that off). Remove the stencil paper.
Lay the marked aluminum sheet on a work table that you don't mind cutting into a bit, or place some scrap material underneath your sheet to protect the work surface. Clamp to table. While wearing safety glasses and dust mask, carefully cut out the design. The interior is a little tricky. Alternatively, you may need to gently perforate the interior bowl of the "U" with a nail and hammer if your cutting attachment is too large, although you risk denting the design if you aren't careful.
Careful removing the cut design from the sheet as the metal is VERY sharp. Work gloves are highly recommended at this point.
Remove the cut "U" from the sheet. Sand down the edges with a sanding attachment on your rotary tool or by hand with the 120 grit sandpaper. Once you've sanded the "U" to your liking, making sure to round out all pointy bits, sand the face of the "U" with the fine grit sandpaper to remove any stencil marks and to give it a uniform finish.
Insert the screw in the split key ring as indicated. Try to position the top of the pendant where the ring opening is located.
Apply a piece of masking tape to the finished side of the "U", leaving enough tape to attached to the ring sides. Position the "U" on top of the screw and tape into place.
Place the pendant, finished/taped side down, on a piece of paper or some other surface you don't mind getting glue or solder on, and something that can be easily removed if you accidentally glue the pendant to the surface. Apply glue or solder "U" to the screw at the two contact points, making sure to get into the groves. Apply glue or solder to the screw at the points it makes contact with the ring. Allow glue to dry completely before moving on. (Note: If soldering, you'll have to do some extra prep work on the aluminum to allow the solder to stick. I was too impatient to prep and tin the surface for this method.)
Once dry, place the jump ring on the pendant. Hang the pendant from the jump ring and position so everything is centered. A helping hands tool is very handy for this. Apply a small amount of glue (or solder) to the point where the jump ring touches the pendant--watch out for dripping. Allow to dry completely.
If you used super glue, you may notice some haze on the metal, especially the aluminum. This can easily be removed with gentle sanding being careful not to break the glue bonds.
String the necklace chain through the attached jump ring and the necklace is now complete! YAY!
Additional Resources for Ghostbusters Cosplay
(More to be added as I find them. Find any fun links? Let me know in the comments!)
For those wanting to buy a pre-made "Screw U" necklace, a different version is now available at Optimystical Studios!