Custom Robot Keychains with Easy Moldmaking

Step #1: Create a robot you want to share with others.

I took our Makey robot icon and 3D-printed a small copy for myself. I am going to use this to make copies for my friends. Not everyone has a 3D printer, so you can sculpt your own, or build one from parts around the house. Use thin wood, strips of styrene, or even thick hard clay.

But remember, try to keep a flat back on one side, which will make it easier to mold.

Step #2: Prepare the silicone.

NextPrev

I picked up some silicone putty from the art store. If you can't find any in your town, you can order different brands from Smooth-On.
Mix equal parts from the 2 containers. You will have to guesstimate how much you'll need.
Read the directions to see how long you have to mix before it hardens. Use nitrile gloves (not latex, as it will impede the silicone from hardening), and mix the 2 parts together until there is a uniform color.

Step #3: Make the mold.

NextPrev

Working quickly, press the silicone into all the nooks and crannies of your piece. Make sure the silicone wall around the piece is thick enough (I usually try to have .25" minimum around the object I'm molding). Leave more silicone on the top.
The added silicone on top is so that you can press something flat onto the top, leveling it off. That way, when you flip this mold over to pour resin into it, the mold lies flat on your table, and the resin will fill the entire mold evenly.

Step #4: Prepare the resin.

NextPrev

Most resin comes in 2 parts. You measure out equal parts into 2 measured devices. I use clear disposable cups and eyeball the amounts.
I could paint the robots after I cast them (resin usually cures white or off-white), but instead, I used resin dyes. Just a few drops mixed into either part A or part B of the resin will make the piece entirely colored throughout.

Step #5: Pour your first copy.

NextPrev

Slowly mix the 2 parts of the resin together, and make sure you read the directions of your brand of resin. You only have a specific amount of time after you have mixed the 2 parts before the hardening process starts. Try not to add air bubbles with over-vigorous mixing.
Slowly pour the resin into the mold, and try not to spill it over the top of the mold. After a few minutes, the resin will start to harden, whitening a bit.

Step #6: Remove the robot, and drill.

NextPrev

After you are sure the resin has cured completely, carefully remove it from the silicone, taking care not to tear the silicone. You might need to clean up the edges. Take a little sandpaper to the edges to get rid of the excess resin, which is called "flashing."
Plan out where you want the hole to be drilled, and make sure it isn't too close to the edges of the robot. You don't want the resin to break due to a thin wall.
Add the robot to your keychain and wear it proudly!

Step #7: Dress it up!

NextPrev

I made a bunch of copies in different colors, but I wanted one to look like it was metal.
I dry-brushed silver metallic paint over the keychain, and specifically on the edges, making it look like worn metal. You could paint your friend's name on the back or draw faces on it in paint. This doesn't have to be just a keychain, either. This idea would be great for necklaces, bracelets, or tiny party favors. Have fun and show us what you make!

Projects from Make: Magazine

Parts

Tools

Steps

Step #1: Create a robot you want to share with others.

Step #2: Prepare the silicone.

Step #3: Make the mold.

Step #4: Prepare the resin.

Step #5: Pour your first copy.

Step #6: Remove the robot, and drill.

Step #7: Dress it up!

Jason Babler