How to Make Slime (Classic Recipe)

Simple Recipe for Borax and Glue Slime

Slime
You can alter the consistency of slime by changing the ratio of ingredients. Dorling Kindersley / Getty Images

There are lots of recipes for slime. Which one you choose depends on the ingredients you have and the type of slime you want. This is a simple, reliable recipe that produces classic slime.

What You Need to Make Slime

  • Borax powder
  • Water
  • 4 ounce (120 ml) glue (e.g., Elmer's white glue)
  • Teaspoon
  • Bowl
  • Jar or measuring cup
  • Food coloring (optional)
  • Measuring cup

How to Make Slime

  1. Pour the glue into the jar. If you have a big bottle of glue, you want 4 oz or 1/2 cup of glue.
  1. Fill the empty glue bottle with water and stir it into the glue (or add 1/2 cup of water).
  2. If desired, add food coloring. Otherwise, the slime will be an opaque white.
  3. In a separate, mix one cup (240 ml) of water into the bowl and add 1 teaspoon (5 ml) of borax powder.
  4. Slowly stir the glue mixture into the bowl of borax solution.
  5. Place the slime that forms into your hands and knead until it feels dry. Don't worry about the excess water remaining in the bowl.
  6. The more the slime is played with, the firmer and less sticky it will become.
  7. Have fun!
  8. Store your slime in a zip-lock bag in the fridge (otherwise, it will develop mold).

How Slime Works

Slime is a type of non-Newtonian fluid. In a Newtonian fluid, viscosity (ability to flow) is only affected by temperature. Typically, if you cool a fluid down, it flows more slowly. In a non-Newtonian fluid, other factors besides temperature affect viscosity.

Slime viscosity changes according to pressure and shear stress. So, if you squeeze or stir slime, it will flow differently than if you let it slide through your fingers.

Slime is an example of a polymer. The white glue used in the classic slime recipe is also a polymer. The long polyvinyl acetate molecules in glue allow it to flow from the bottle.

When polyvinyl acetate reacts with the sodium tetraborate decahydrate in borax, protein molecules in the glue and borate ions form cross-links. The polyvinyl acetate molecules can't slip past each other so readily, forming the goo we know as slime.

Tips for Slime Success

  1. Use white glue, such as Elmer's brand. You may also make slime using the clear or translucent school glue. If you use white glue, you get opaque slime. If you use a translucent glue, you get translucent slime.
  2. If you can't find borax, you can substitute contact lens solution for the borax and water solution. Contact lens solution is buffered with sodium borate, so it's basically a pre-made mixture of the key slime ingredients. Don't believe internet tales that "contact solution slime" is borax-free slime! It's not. If borax is a problem, consider making slime using a truly borax-free recipe.
  3. Don't eat the slime. Although it isn't especially toxic, it is not good for you either!
  4. Slime cleans up easily. Remove dried slime after soaking with water. If you used food coloring, you may need bleach to remove the color.
  5. I've got a YouTube video of the slime showing what you will get if you use glue gel rather than white glue. Either type of glue works well.