What contact solution does for slime

Contact solution is a liquid that activates slime by triggering a chemical reaction with borax or other slime activators. When you mix contact solution with glue and an activator, the solution causes the mixture to thicken and become stretchy instead of staying runny. The active ingredient — usually boric acid — bonds with the activator to form the slimy texture you're looking for.

Contact solution works because it contains a mild acid that reacts with borax or sodium tetraborate. This reaction creates long chains of molecules that trap air and water, giving slime its characteristic feel. Without contact solution or a similar activator, your glue mixture will stay liquid no matter how long you stir it.

You can buy contact solution at any drugstore or supermarket in the eye care aisle, usually for $3 to $8 per bottle. But if you don't have any on hand or want to avoid buying it, you can make a working substitute using common household items.

Key Takeaways

  • Contact solution activates slime by reacting with borax or another activator to create the stretchy texture.
  • You can make a substitute by mixing boric acid powder (found in the laundry aisle) with water in a 1:16 ratio.
  • Saline solution from a drugstore works as a direct replacement if you have it but don't want to use it for your eyes.
  • Borax solution itself — borax mixed with water — can replace contact solution if you adjust your recipe to use less borax powder.
  • Always wear gloves when handling borax or boric acid, and keep slime away from eyes and mouth.

Making contact solution from boric acid powder

The easiest substitute is to make your own contact solution using boric acid powder, which you can find in the laundry aisle of most supermarkets for $2 to $4. Boric acid is the active ingredient in commercial contact solution, so a homemade version works just as well for slime.

Mix one teaspoon of boric acid powder with 16 teaspoons (about one-third cup) of water. Stir until the powder dissolves completely — this takes about two minutes. The mixture should be clear. Use this homemade solution in place of contact solution in any slime recipe, measuring it the same way you would measure store-bought contact solution.

Store your homemade contact solution in a sealed container away from children and pets. It keeps for several months. Label the container clearly so no one mistakes it for something to drink or put in their eyes.

Using saline solution as a direct swap

If you have saline solution at home — the kind used for cleaning contact lenses or rinsing eyes — you can use it directly in slime recipes without any mixing. Saline solution contains boric acid or similar compounds that set up slime the same way commercial contact solution does.

Use saline solution in the exact same amount your recipe calls for contact solution. The results will be identical. This option works well if you have an old or opened bottle of saline solution you're not using anymore, since saline is safe to use on skin and eyes, making it a lower-risk choice if slime accidentally touches your face.

Making slime with borax solution instead

You can skip contact solution entirely and use a borax solution — borax powder mixed with water — as your activator. This method requires adjusting your recipe because you're adding both the activator and the liquid at the same time.

Mix one teaspoon of borax powder with one cup of warm water and stir until the powder dissolves. This is your borax solution. In a separate bowl, pour four ounces of white school glue and add food coloring if you want colored slime. Slowly add the borax solution to the glue while stirring constantly. Stop adding solution when the slime pulls away from the sides of the bowl and becomes hard to stir — this usually takes about half a cup of borax solution.

The slime will be stiff at first. Knead it with your hands for a minute or two until it reaches the stretchy texture you want. If it's too stiff, add a few drops of lotion or baby oil and knead again. If it's too sticky, mix a tiny amount of borax powder directly into the slime and knead it in.

Other household activators that work

If you don't have contact solution, boric acid, or borax on hand, a few other items can set up slime. Liquid starch — the kind used for ironing clothes — works well and is gentler to handle than borax. Mix four ounces of glue with one tablespoon of liquid starch and stir until the slime forms. Add food coloring before mixing if you want color.

Cornstarch mixed with water can create a slime-like substance, though it won't be as stretchy as borax-activated slime. Mix one cup of cornstarch with one-half cup of water and stir until you reach the right consistency. This version is completely safe to touch and tastes bad enough that children won't want to eat it, but it dries out faster than other slime types.

Dish soap mixed with glue and a small amount of borax can also work, though the texture will be more bubbly and less stretchy. Experiment with small batches to find what works best with the materials you have.

Safety when making slime at home

Borax and boric acid are safe for slime-making when used as directed, but they should not go in eyes or mouths. Always wear gloves when handling borax powder or boric acid, and wash your hands after playing with slime. If slime gets in someone's eyes, rinse with water for at least 15 minutes and call poison control if irritation continues.

Keep slime away from very young children who might try to eat it. Store all powders and solutions in labeled containers on a high shelf. If someone swallows slime, call poison control at 1-800-222-1222 — they can tell you whether the amount matters and what to watch for.

Supervise children while they're making and playing with slime. Slime can stain clothing and carpet, so use a table you don't mind getting messy, and keep slime away from fabric furniture.

Frequently Asked Questions

Can I use regular saline solution from the drugstore?

Yes. Any saline solution labeled for contact lens care or eye rinsing will work in slime recipes. Use it in the same amount your recipe calls for contact solution. Avoid saline solutions that contain hydrogen peroxide, as those are meant for specific lens types and won't set up slime the same way.

What if my homemade contact solution is cloudy?

Cloudiness usually means the boric acid powder didn't dissolve completely. Stir the mixture for another minute or two. If it still looks cloudy after five minutes of stirring, the water may be too cold — try warming it slightly and stirring again. Cloudiness won't affect how well it works in slime.

Does the type of glue matter when making slime?

White school glue works best and is what most recipes call for. Clear glue also works but produces transparent slime instead of opaque. Avoid craft glues labeled as "tacky" or "thick" — they're already partially activated and won't mix properly with contact solution.

How long does homemade slime last?

Slime made with borax or contact solution typically lasts two to four weeks if stored in an airtight container. It will eventually dry out and become hard. Slime made with cornstarch dries faster — usually within a few days — so make smaller batches if you use that method.

Is it cheaper to make contact solution than to buy it?

Yes, slightly. A box of boric acid powder costs $2 to $4 and makes enough contact solution for dozens of slime batches. A bottle of contact solution costs $3 to $8 and makes fewer batches. If you're making slime regularly, buying boric acid powder saves money over time.