PolyVinylAlcohol Slime (PVA Slime)
Most plastics do not dissolve in water. PVA on the other hand is one of the few plastics that can dissolve in water. When PVA dissolves in water it becomes a water based adhesive. This water based adhesive can harden in the form of slime by adding borax solution. Because PVA is a water soluble plastic, the slime made of PVA is more resistant to environmental microbes and will last longer. Most professional quality slime such as those used in movies or in science shows are made of PVA.
MiniScience Slime Science set includes 50 grams of PVA and this amount is sufficient for 2 to 3 pounds of slime.
If you need to purchase more PVA for a science camp, movie production or large group of students, please be careful about the PVA grade you order. I recommend PVOH4988 or PVOH2588. These two grades can dissolve in room temperature water; however, warming up the water along with continuous stirring can expedite the dissolving process.
Warning: This project requires adult support and supervision. Preparation of materials in most cases must be done by an educated adult. It will take at least 2 hours to prepare the materials.
Prepare your materials
Step 1: Dissolve the Polyvinylalcohol in water and make a 4% solution.
In a steel or aluminum saucepan add 1250 ml water (5 of the blue measuring cup). Add the entire 50 grams polyvinylalcohol to the saucepann. At this time mark the water level so that you can readjust the amount of water later if part of the water is lost due to the evaporation. Let the polyvinylalcohol soak in water for about 2 days and stir the mixture a many times each day. After 2 or 3 days of soaking, warm up the pot over the stove and continuously stir the mixture until fully dissolved and a clear homogenous solution is formed. Transfer this solution to a jar or bottle and label it as “PolyVinylAlcohol, 4% solution”.
Step 2: Dissolve the Borax in water and make a 4% borax solution.
The Slime Science Set includes 25 grams of borax (BORAX10). Dissolve the entire 25 grams of borax in 600 ml (about 2.5 cups) of warm or hot water. Stir it until fully dissolved and the solution becomes clear. Let it cool down and then store in a clean bottle or jar and label it as 4% Borax Solution. (This borax solution is enough for many slime experiments. Use it for PVA slime, Guar gum slime and many others. A few teaspoons of this solution is usually enough for one cup of slime)
Make your first slime:
In a science lab we use a beaker to make the slime. If you do not have a beaker, you may use a disposable bowl or cup to make the slime.
- Transfer 1/2 cup of the PVA solution to a clean beaker (or disposable bowl/cup).
- At this time if you want your slime be colored, you can add a few drops of food coloring.
- Add one tablespoon borax solution while stirring with a spoon.
Note: The amount of borax solution you add to the PVA solution can be anything between 1/20 up to 1/2. (For example if you have 20 mL of PVA solution, you can add 1mL up to 10mL borax solution). The more borax you add, the more cross-links will be formed and the slime will be harder.
After you make your slime, you may place it in a bag for future use or display at the science fair. A plastic bag can keep your slime fresh and protect it from drying out.
For students and small classrooms, the Slime Science Set has all you need to make varieties of slimes. If you have access to food coloring, you can add a few drops to your PVA solution to make colorful slime.
This set contains 50 grams of PVA and 25 grams of Borax. This amount of borax is enough for many slime experiments.
More about PVA Slime (also known as Polyvinyl Alcohol, PVOH or PVOH4988)
PVA slime is often referred to as “institutional” or “commercial” slime. This is the type that is generally found in toy stores. It is a little trickier to make, the main ingredient (polyvinyl alcohol PVOH4988) is only available in large quantities (at least one pound). One pound of PVOH4988 will produce more than 25 lbs of slime. Obviously this is much more than what a student may need. But it produces a superior slime. Longer lasting, more transparent, and with a visual and tactile appeal that is more, well, “slimy”.
Assuming you are a teacher and can get hold of PVA (from ChemicalStore or ScienceKitStore), it is a fairly simple process to make slime. First, mix a 4% solution of PVA and water. 4 % would be 40 grams of PVA to 960 ml of distilled water (of course you can adjust and make more or less). It helps to have a heated magnetic laboratory stirrer (don’t use one of your good kitchen saucepans – it’s best to use Pyrex lab ware). Slowly, gradually, mix the PVA into the distilled water. Heat it slowly, stirring the whole while, until the PVA goes into solution. This will take 30 minutes or more. Do not let it boil. Once cool, the solution can be stored in a stoppered bottle.
The 4% Borax solution is made by dissolving 4 grams of borax into 100 ml of distilled water. It should go into solution without heating. This can also be stored in a stoppered bottle.
Mix the two solutions in a glass or ceramic bowl. Do not use plastic. Start with the PVA solution, and stir in the coloring, if used, and borax solution. The standard ratio is 5 parts PVA solution to 1 part Borax solution. This works well, but ratios have been quoted bother slime makers as 6:1, 20:3, and as high as 200:15 (app. 13:1). The best bet is to start with the basic 4% solutions at 5:1, adjusting the ratio as necessary to get the consistency you want. Store in a sealed container. No need to refrigerate. Keep it clean and it should last indefinitely.
Some archival art glues are actually a 5% PVA solution. It is almost certainly more expensive to purchase the glue than it would be to purchase the PVA, but, if you do happen to have a bottle around the house that you probably wouldn’t use otherwise, it should work (check the ingredients!) PVA is also sold as a mold release agent for fiberglass molding, etc. Check with supply houses for molding, boat repair, or auto painting. Also, some soluble bags used in hospitals are made of PVA. If anyone knows how to make slime from these, I would like to hear about it.