Create Your Own Cast and Oogoo to Give Your DIY Gadgets the Shape You Want

I think it's fair to say that every maker yearns for a 3D printer. You can replace circuit board connectors, fix your glasses, create ski grips, and make whole machines out of printed plastic parts—even a 3D printer. But without a 3D printer on hand, you can always resort to Sugru.

Sugru is a silicone rubber putty that dries semirigid and has super strength. While it is cheaper than a 3D printer, Sugru comes in tiny packages and in a limited number of colors. We need something cheap and customizable. So, today we make some DIY silicone rubber, aka Oogoo, using just cornstarch and silicone caulk.

Materials

• 100% silicone clear caulk
• 100% cornstarch
• Mold or object to copy
• Linseed oil paint
• Rubber gloves
• Face mask
• Goggles

What to Make?

The possibilities with Oogoo are endless. Encase a phone, make circuit board bumpers, create a frisbee, cast robot parts—the world is your oyster. Whatever you end up making, you will need a mold of the object you want to create. You can use Plaster of Paris to make a mold of an original object.

I decided to make a small project box for my first Oogoo casting. I placed one tin inside of another to create the space for the mold.

I taped the sides of the inner tin so as to suspend it and leave room for the Oogoo to flow underneath.

Mix Oogoo

All you need to do is add some cornstarch to the silicone. Make sure you wear gloves as silicone is inherently evil and will piss you off for days if you get it on your hands. Some people complain of mild allergic reactions if not wearing gloves, too. Also wear your goggles and safety mask at this point. There is no real danger, but the fumes given off by the mixture are not pleasant.

I used a Dixie Cup to mix in. If you are filling multiple molds, you will want a bigger container.

A one-to-one ratio of starch to caulk will dry in a few hours. Less starch means a longer drying time. I found that the one-to-one ratio was too thick and would not flow into the mold like I had wanted. I ended up going with a ratio of 2 parts silicone to 1 part starch by volume.

The mixture is tricky to stir, but keep at it! It will blend! Adding linseed oil paint now will give your Oogoo some vibrancy, as well as help you see when an even mix has been achieved.

Set

Pour the mixture into the mold and let it set. Wait for at least two hours before examining your Oogoo. Remove the mold from the Oogoo by breaking the plaster or metal mold apart. You can also use a butter knife to pry the Oogoo out if your object has flat sides like the tin. Oogoo is very flexible and will easily pop out without breaking. It should have a shiny white finish.

Oogoo peels easily off of plastics and metal.

Profit

Now you are only limited by your mold-making skills. Play around with different ratios and see what works best for your projects. Remember, you can cast very thick objects like robot limbs as well as thin place mats and throwing discs.

My first Oogoo attempt ended in failure. I use too much starch and the mix solidified too fast to take the full shape of the mold.

Despite the failure, the bottom of the Oogoo piece did come out shiny and flat!

Now I have an Altoids tin mold made from Oogoo! I would like to embed some Altoids-sized circuits in an Oogoo mold. Oogoo would essentially act as a removable shockproof circuit board.

My second attempt at an Altoids lid casting went quite well!

The tin and body molds fit perfectly into one another

It would be easy to apply this same technique to creating valves, servo mounts, watches, and underwater electronics enclosures. Oogoo is definitely my new circuit board of choice for all portable projects. It's dirt cheap, waterproof, shock resistant, and customizable!

What would you use Oogoo for? Share your Oogoo projects with the whole community by posting them on the corkboard. Join the conversation in our forum and always feel free to ask questions in the comments below.