This is a simple way to make a silicone wedding band of any ring size. Traditional wedding rings can pose many safety hazards, sometimes leading to pretty gruesome injuries (a quick Google search of Jimmy Fallon's wedding ring injury will show a high profile example). If you are constantly removing your wedding band for shop work, the gym, electrical work, whatever it may be, a silicone ring can be a great set-it-and-forget-it option. In an event where a typical ring could get caught and cause significant injury, a silicone band will simply stretch and eventually tear. Here is a simple guide to make your own silicone wedding band and keep your finger in one piece!
Step 1: Tools and Materials
Here is a full list of needed tools and materials. Most can be found locally or on Amazon.
1) 3D Printer (I'm using a Zortrax M200. If a 3D printer in not an option, download the included files and get them printed on 3Dhubs.com ). I printed in ABS. Have not experimented with other filaments.
2) 2 Part Platinum Cure Silicone (Any two part will do, but higher durometer is better. Smooth-On Dragon Skin 30 is a good skin safe silicone for this application.)
3) Syringe (Can usually get some free oral medication syringes at your local pharmacy. Or you can buy a pack on Amazon.)
4) Vacuum Chamber and Pump (Optional, but highly recommended. These can be a little pricey, but a must-have for any fabrication shop. These are good for the price.)
5) Plastic Cup
7) Toaster oven or conventional oven
Step 2: Mold Printing
You will need to print two part files for this project. Find your ring size for both the "Vent Cavity" and "Inject Cavity". My print settings can be seen in the attached picture, and are as follows:
Layer Height: 0.15mm (150 micron)
Infill: Full (not necessary, but will help with a later step)
Supports: None / Not Necessary
When printing, just lay the pieces flat on their back as seen in the picture. This should result in no needed supports and a ready to use mold. The pegs should fit right off the printer, but depending on the printer used, you may need to shave down the pegs to get a good fit. Make sure the two mating faces fit flush when pressed together. If not, trim pegs and holes until the faces sit flush.
Note: There are a lot of STL files here. If there is an error with a certain size, please do not hesitate to message me directly. All files were created using SolidWorks 2016. And yes, I created every single ring size...
Step 3: Silicone Preparation
Now that you have your 3D printed molds ready to go, it is time to get your silicone prepared. All 2 part silicones have a pot life, meaning you have a limited amount of time to work with it before it starts getting too thick to work with. This time will be unique to each silicone. For best results, it should take no more than 5-10 minutes between mixing your silicone and injecting it into your mold.
Mix your silicone part A and part B according to manufacturer instructions in a plastic cup (if using Dragon Skin 30, it is just 1:1). The mixing process will produce a large amount of bubbles. To get rid of the bubbles a vacuum chamber will be needed for this step (A bunch of small bubbles actually look kind of cool, but if you inject a very large bubble, it will cause a large void in the ring). Place the cup in the vacuum chamber, and pull as close to a full vacuum as your equipment is capable of. In my case 26.5 in Mg was sufficient to remove all the bubbles in about 1 minute.
With your silicone ready to go, it is time to move quickly to the next step.
*NOTE: For a light coloring like the pink ring pictured, simply use 1 or 2 drops of food coloring. The result will be a light but translucent coloring. For a fully opaque coloring, purchase a silicone colorant from the manufacturer of your two part silicone.
Step 4: Injecting the Silicone
Now that all the hard work is done, it is time to fill up your printed mold cavities with your prepared silicone.
DO NOT pull the silicone into the syringe through the tip! Pulling the silicone through the tip will add bubbles to your silicone mixture.Instead, remove the plunger from the syringe and slowly pour the silicone into the syringe through the top. Fill the syringe ALL THE WAY. Yes, this will be a little messy, but it will prevent a big air bubble from getting in when you put the plunger back in.
Assemble your mold cavities and clamp them together. Make sure the vent hole (small) and inject hole (large funnel) are on OPPOSITE sides (i.e. vent on left, inject port on right). The purpose of this vent hole is that when you begin injecting the silicone, the air already inside the cavity has to go somewhere. So all the air escapes out the vent hole as it begins to fill with the silicone.
Squeeze out any air from the bottom of your syringe, and then place the tip into the injection port (funnel hole), pressing firmly, and inject the silicone liberally. Silicone should flow out of the vent hole, and will most likely squeeze out the sides as well. Wipe up any excess, and throw in a toaster oven or conventional oven at 180-200° F for the duration of the cure time of your particular brand of silicone.
Step 5: Clean Up and Finish
After the silicone has sufficiently cured, it is time to finish up your new ring.
At the injection port, grab some of the silicone, pull it up, and cut the external glob that cured in the injection funnel. This will prevent it from ripping off the ring in an ugly fashion when you separate the mold cavities.
Next, pry the mold cavities apart with a small screwdriver. You will see a lot of flash around the ring (flash = unintended plastic cured at the mold parting line). Don't worry yet, just pull the ring out of the mold. Silicone is resilient, no need to be gentle. Once out of the mold, trim the vent port off.
For the flash, simply pull on it firmly. It will peel off fairly clean. Trim any excess with needle nose pliers by simply grabbing on the flash and peeling it off.
With all the flash removed, you are finished! Enjoy your new ring, print out some different sizes, and make one for your spouse!