Endless Mysteries of Bouncing Putty

Real Bouncing Putty is expensive because it is made from silicone polymers. These silicone materials are an order of magnitude pricier than the chemicals which trace their routes back to an oil well.

Because of this, there are a lot of products which claim to be bouncing putty but, in fact, are not.

PRODUCTS THAT ARE *NOT* BOUNCING PUTTY

Mars Mud
Noise Putty
Slime
Any kind of clear or translucent putty

PRODUCTS THAT ARE BOUNCING PUTTY
Silly Putty
Thinking Putty
Ja-Ru Putty
Most Therapy and Exercise Putty

The products that are not Bouncing Putty are usually a modified version of PVA (polyvinyl alcohol) slime. They may be fun to play with for a minute or two, but their wet, clammy feel doesn't lend itself to long term use. They tend to have an odor which remains on the hands and they dry out fairly quickly if left in an unsealed container.

The products which are Bouncing Putty fall into three categories:

- Toy & Novelty

Silly Putty and Thinking Putty are both high quality Bouncing Putty products which are optimized to look good and feel good. They will not dry out, will not become dirty too quickly, and they have no offensive odor. They are designed for play and stress relief

- Low-Cost Toy & Novelty

These products aim to achieve the same goals as Silly Putty and Thinking Putty. However, in an attempt to save on manufacturing costs, they are loaded with filler materials. These fillers detract from the color, translucency, bounciness, tearing ability, or other special physical properties that make Bouncing Putty special.

- Exercise and Therapy Putty

These putty products are designed for medical use. They are available in different hardnesses, usually indicated by color. They aren't designed to be particularly attractive. Their goal is to be utilitarian. Many use fillers as a means of altering the resistance the putty offers. They are availble in extremely soft to extremely hard versions depending on your injury or level of exercise.

Elmer's Glue and Borax approximate the structure of a silicone Bouncing Putty. Instead of using silicon atoms as the heart of the polymer chain, they use carbon, just like regular plastics. When you add borax to Elmer's Glue you encourage the long glue molecules (imagine they look like a freight train) to stick to each other.

You end up with a thick tangle of threads not unlike a big bowl of spaghetti. If you try to shape the spaghetti ball slowly, each long thread has time to slither into a new position and find new neighbors to snuggle up with. If you try to shape the spaghetti ball too quickly, things tear apart.

This is a fun experiment which is easy to do at home. All of the ingredients can be found around the home or at the grocery store. The downside of this material? It isn't very durable. It won't last very long. It doesn't have that non-messy feel of a real bouncing putty.

The next step for an experimenter is to make real 'slime' using polyvinyl alcohol (PVA). By mixing PVA with Borax, you get the same basic structure. The PVA material is more durable but won't last forever. Its properties will change depending on the humidity of the air around it. It can be crystal clear, which is very cool. However, it doesn't really have the same stretching or bouncing capabilities as a true Bouncing Putty.

For the hard-core experimenter it isn't difficult to make the real thing. Use Boric Acid instead of Borax. 99% Boric Acid can be found as white powder used as an ant & roach killer. Most grocery or hardware stores carry it. And don't worry, while it is non-friendly to bugs, it is mostly harmless to humans. Just wash hands and use general lab cleanliness precautions.

Mix about 5 grams of Boric Acid with 95 grams of hydroxy-terminated polydimethylsiloxane. You'll have to dig a little deeper into your chemistry kit to find the second ingredient. You'll want to keep the Boric Acid from settling to the bottom of your container. Once you've figured out how to keep that from happening, just heat the mixture at around 350F for a few hours. Check on it occassionally and stir. Voila! Putty.

Real Bouncing Putty has delicate qualities. It can be drawn into the thinnest of strings without breaking. It can snap into two pieces crisp and clean. It bounces. It doesn't feel wet or slimy or have a bad odor. A modern miracle!

Not the kitchen chemistry type? Thankfully you can get your Bouncing Putty fix from a variety of companies.

Silly Putty clearly has the most name recognition. The tiny plastic eggs have been around for over 50 years every since they made a smash hit at the New York Toy Fair. You get 1/34lb for about $2.00. It is available in about 10 different colors (fluorescent, tan, primary colors, etc).

Thinking Putty is a little less well known. The company sells its putty in metal tins with 1/5lb or in 1lb bags. The company offers over thirty colors including heat sensitive hypercolors, glow in the dark, metallic, and even a magnetic variety. You'll need to order online as the product isn't available at mass market retailers.

Vern's Putty List has been active on the internet for well over 10 years. Sign up and join a hard core group of putty heads as they pool together to purchase 50, 100, or even 150lb blocks of raw, uncolored putty. A lot of list members experiment with coloring the Bouncing Putty themselves and there is a lot of discussion about which Arts & Craft store products do the best job.