How to Make Plaster of Paris Stronger

While making casts and sculptures for your garden, you might have wondered how to make plaster of Paris stronger. When mixed with water, it can be molded and used in many ways from sculptures to modeling. Basic plaster of Paris mixture is hard, but it can be fragile when it is dried. This can be a problem if you will display your garden sculptures in an area where they are exposed to various weather conditions. To help you with this problem, we have shared different ways on how you can make plaster of Paris more durable.

How to make plaster of Paris stronger? To make the plaster of Paris stronger and more durable, you can mix it with glue. Pour 1 ¼ cup of water in a mixing bowl and add ¼ cup of glue and mix it. Slowly pour two cups of plaster of Paris into the mixture. Let the plaster rest for about five minutes before mixing it again. The glue will strengthen the mixture making it last for a long time.

How to make plaster of Paris waterproof? What is stronger than plaster of Paris? Why is plaster of Paris easy to break? These are some of the questions that we will discuss in this article. If you are interested in making the plastic of Paris stronger so that you can use it for your home and garden, you can check out the rest of the article below for more tips and information. We share different ways on how to make the plaster of Paris stronger. Moreover, we will discuss important things that you need to know on how to make plaster more durable.

How to Make Plaster of Paris Stronger
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How Can I Make Plaster of Paris Stronger?

Adding glue to the plaster of Paris and water mixture can strengthen the plaster and make it last longer. This also makes the plaster of Paris harder so that it can be strong enough to be sanded with fine-grit sandpaper. The basic glue and formula are ideal for small plaster projects. You can use the same formula for larger projects by scaling it up as long as you make sure that the ingredients and ratio used are the same.

How do You Make Plaster of Paris Less Brittle?

Below are the materials and instructions on how to make plaster of Paris less brittle.


  • Plaster
  • White glue
  • Water
  • Old newspapers
  • Measuring cup
  • Mixing bowl
  • Spatula


Step 1: Prepare the Area

Cover the work area with newspaper to prevent the plaster from sticking to the surfaces.

Step 2: Mix Water and Glue

Pour 1 ¼ cup of water into the mixing bowl. Add ¼ cup of white glue into the water. Mix them until the glue is thoroughly dissolved in water. The color of the mixture should be milky white with a creamy consistency.

Step 3: Add Plaster to the Mixture

Pour 2 cups of plaster of Paris into the mixture. Sprinkle a small amount of plaster across the surface of the mixture. Do not stir the mixture because it can cause air bubbles that can weaken the plaster. Allow the plaster to settle to the bottom. Continue to pour the plaster of Paris until you have used all two cups.

Step 4: Allow the Mixture to Rest

Allow the plaster to rest for about five minutes before mixing.

Step 5: Use the Plaster

Use the plaster immediately.

✅ Video – How to Mix Plaster of Paris Technique the Easy Way for Superior Strength

For a visual demonstration, you can watch the video below shared by Environ Molds on their YouTube channel. It shows the steps on how to create high-quality plaster art castings with superior strength and resistance to chipping. This method will make the plaster stringer and also durable. You can try this technique at home when making small sculptures for your garden and home decoration. Click the play button for the complete demonstration.

Can You Make Your Plaster of Paris?

You can make your plaster of Paris by using Paris powder and mixing it with water. Another substitute that you can use if you do not have Paris powder is white glue and white flour. This is an affordable and easy way to make your plaster that you can use at home. Plaster made from glue or flour can be used to seal small cracks and holes in your walls. It only takes a few minutes to make and is also easy to apply.

How to Make Plaster from Glue

Glue makes a good substitute for plaster of Paris. Mix 1 cup of water with 2 cups of school glue (white glue). Pour the water and glue it into the mixing bowl and stir thoroughly until it has a soupy consistency. Immediately work with the plaster because it can set after 15 minutes or so. This is a great idea if you are making crafts with your children. You can make plaster handprints and fingerprints out of water and glue.

For more information about making your plaster, you can check out this article that we have written which discusses how to make homemade plaster. We have shared the common and easy steps that are used to make plaster at home.

How to Make Plaster of Paris Waterproof

Plaster of Paris is a porous material when dried and will absorb water that touches the surface. To waterproof it for outdoor use, you can coat it with a waterproofing agent. Though you cannot create a perfectly waterproof plaster of Paris piece, you can provide it with some degree of protection from the elements. Below are the steps on how to waterproof plaster of Paris.


  • Waterproofing agent
  • Paintbrush
  • Paint
  • Clear sealer


  1. Allow the plaster of Paris sculpture to thoroughly dry.
  2. Coat the plaster with a waterproofing agent like marine resin that penetrates through the surface pores. Allow it to completely dry.
  3. Reapply the waterproofing agent as needed to completely seal the plaster sculpture, allowing each layer to dry completely. Once it is dried, you will have a plain waterproof plaster sculpture.
  4. Apply the paint colors as you want over the dried waterproofing agent and let dry thoroughly.
  5. Spray the sculpture with a clear sealer or shellac to protect the paint job. Allow the sealer to dry before displaying the plaster sculpture outdoors.

Does Plaster of Paris go Bad?

The gypsum plaster itself does not expire. On the other hand, the retarders that prevent the plaster from setting quickly can expire. After some time, bagged plaster can get stiffer because of moisture absorption. It can even clump together due to the moisture reacting with the plaster.

Is Plaster of Paris Easy to Break?

The plaster is fragile and brittle and will break if knocked hard enough or dropped. Moreover, it is soft and can scratch easily. Moisture and humidity are also a concern with plaster as it is highly soluble in water and can disintegrate after prolonged exposure to high humidity. Plaster is also porous and if unsealed, it can absorb dirt and grime.

What is Stronger than Plaster of Paris

Hydrocal is considered stronger than plaster of Paris. Aside from being strong, it also takes lots more detail and does not slough off. These factors are important for a sculpture or cast to last longer. The sloughing of plaster can result in continuous dusting and chipping. To prevent this, you can seal the plaster of Paris. However, mot sealers cause the plaster to have a sheen, are unable to take stains, and do not make the sculpture stronger or damage resistant.

What is Hydrocal?

Hydrocal is a good substitute for plaster of Paris. It is a gypsum product that is usually used for slip latex mold sand case molds. Hydrocal offers a slightly better heat resistance than pottery plaster with higher dry and wet strengths. Check out this article titled, what is hydrocal for more information.

How do You Harden a Plaster Sculpture?

Some plasters can be hardened by baking them at a relatively low temperature. On the other hand, the best hardener of gypsum (which is what plaster is made of) is time. Keep plaster objects, sculptures, and pieces in a warm and dry environment for many days and their strength greatly increase. On the other hand, they still need to be handled with care because plaster is fragile and can easily break. You can also check out this article that we have written about which type of ceramic is used for making brick. We have shared tips on how to choose the ideal bricks for your home.


In this article, we have learned how to make the plaster of Paris stronger. We also learned that the plaster of Paris is a fragile and porous material that can easily break. It is also sensitive to humidity and moisture. To make it stronger, we can use glue. Mixing glue with the plaster powder can strengthen the plaster and make it last longer. We have shared the steps on how to mix plaster and glue above.

We hope that this article has helped you learn more about how to create stronger and more durable plaster of Paris pieces. If you decide on making sculptures made from plaster of Paris for your garden or backyard decoration, make sure that you thoroughly seal it with a sealant to make it waterproof and to avoid moisture from seeping into the pores of the plaster before you display it outdoors. Thank you for reading!

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