Nothing is more embarrassing than getting to the end of a letter and realizing that you don't have a good wax seal for the envelope. With a couple of easy steps, a 3d printer, a kiln, and a spin caster, you can have a signet ring in no time.
Submitted by Milwaukee Makerspace for the Instructables Sponsorship Program
Step 1: Design the Ring
Using Sketchup or openScad, or your favorite cad design program design a ring. Below is a question block ring I designed using Sketchup. Also attached is an openScad ring designer I am working on. Whatever you want to design is up to you.
If you use Sketchup, there is a variety of plugins you can get to take your design from .skp to .stl. I found one from the makerbot website, and it worked great.
Step 2: Print the Ring
I used a makerbot replicator to print out the rings. From stl file to print is as easy as opening the stl in replicatorG. From there to SD card, it was easy enough to get the printer going. I printed these rings in ABS plastic.
Step 3: Pack the Ring in Investment
After you have your companion cube ring printed out, the next step is to put it on a wax sprue and then mix the investment and pour it over the ring. Unfortunately, I forgot to take a picture of this step, and all I could find was a picture of the side of the cylinder. Inside this cylinder is a ring suspended on a wax stick. I then mixed the investment plaster and poured it over the ring. This dries overnight and sets up inside the cylinder.
Step 4: The Burnout and the Cast
Some guys from Makerbot came by the Milwaukee Makerspace and told us that ABS burns out quite cleanly. Since I assumed that ABS and wax are basically the same burnout profiles, I followed the same burnout for wax using the Kiln at my local makerspace. Follow whatever Temperature profile is your favorite, and burnout the abs ring from the investment.
After the Burnout, when the mold is at casting temp, I put the mold into the spin caster at my local makerspace, melted the bronze grain in the crucible and started the caster spinning.
After the metal cooled down enough, I dropped the mold into water and watched as the water boiled with the sudden infusion of a mold and metal being quenched.
Step 5: Cleanup
After the rings come out of the mold, they are still attached to the tree that was supporting them in the mold. This is now made out of bronze, since the plastic melted out leaving a space in the mold which was filled with molten bronze. The First step is to cut the rings off of this tree and start filing, and cleaning until the plaster is all gone and any imperfections created in the casting process are gone. I didn't get any good before shots of the rings, but my favorite cleaning method for things that have been cast is to soak them in Coca-Cola overnight, and then brush them with an old toothbrush. The best before-after shot I have of this method is on a Bronze Han that I made a while ago. The pictures are from slightly different angles, but they are the same Han frozen in Bronze.
Step 6: The Letter and the Seal
The only thing left to do is to write a letter to a princess that is trapped in another castle, seal it with your brand new signet ring and put it in the mailbox.