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Mold Casting at Home: Step-by-Step Tutorial

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Ms. Millar has been an online writer for 10 years. She enjoys sharing her knowledge with anyone who can make use of it.

Make DIY casting material with this easy-to-follow tutorial. This is a plaster apple.

Make DIY casting material with this easy-to-follow tutorial. This is a plaster apple.

DIY Casting Material: Make a Mold With Simple Materials

I can't tell you how many times I've come across an item that made me think, "I wish I had another one like that" or "If I had that piece, I would paint it with this color instead." Well, I'm happy to tell you that there is a way you can duplicate, replicate, and make your own pieces! The secret is through casting a mold.

When you cast a mold, you are painting a casting material over an item you want to duplicate. When the material dries, you have an exact duplicate of the object!

You can take this to the next level and recreate the item by filling the cast with a material that becomes firm. Then, you peel away the cast and have the item in solid form. This is how busts and some sculptures are made. You can paint them or decorate them however you would like them to be.

The possibilities can be whatever you can imagine. When I have casting down to perfection, I plan on creating sugar art using the moldings I make. Now, I'm sharing what I've learned and done below so you can try this fun project too!

What You'll Need to Cast a Mold


Something to Cast

This is the object (model) you want to duplicate.

Acrylic Lacquer

Needed for porous models like wood.

Casting Material

What you will paint onto your model. I used Mold Builder.

Brush or Sponge

I prefer a sponge, but a brush will work to paint the material onto your model.

Waxed Paper

Needed to protect the surrounding area from excessive splashing or painting.

Step 1: Select Your Model

The first thing you want to do is select what you want to replicate. I purchased a sack of apples the other day and found one to be the perfect example of what an apple should look like. I'm going to use that apple as a model today. You can use almost anything to be a model.

Tip: Don't eat any food you use as a model unless the casting material specifically states it is safe for human consumption!

Step 2: Layer the Casting Material

It's time to layer the casting material. Read the directions on your particular material for any prep work you might need to do on your model before starting the layers. Some casting materials require porous material to be sealed first.

  • It is best to create several thin layers rather than one thick one. I cut off a length of sponge and put a bbq skewer through it as my painting device. You can do the same or pick up a brush at the local hardware store. I like the sponge because the casting material can be thick, pulling the hairs out of some brushes.
  • You don't want the layers to be thick, but you also don't want them to be too thin either. Take your prepared model and brush it on a layer of casting material. Set it aside to dry. On a warm day, give it 15 minutes. On a cooler day, you may need 30 minutes.

When it's dry, most casting material starts out milky white. As it dries on the object, the casting material becomes transparent.

Step 3: Continue Working on the Model

After the one side has dried, flip whatever you are casting over. Paint the other side with the casting material. You will want to keep flipping sides as they dry, so you have a full apple (or object) molding when you're done.

In my example model, I'm going to only put casting material on one side of the apple and plastic horse just for the sake of time. This way, I can show you what the inside of your model will look like.

Step 4: Flip and Layer

Continue flipping and layering until you have about ten layers.

  • I like to let mine dry overnight to make sure it is dry all the way through. Sometimes, it can be hard to tell. If you begin removing the material before it's dry, well, it's not going to end well for your project.
  • The video below shows how to remove the material from your model. It's just like peeling off a tight shirt or nylons. The mold will hold its shape. After you've removed it, just manipulate it with your hands until it's back in its shape.
Plaster of Paris apple

Plaster of Paris apple

Step 5: Fill With Plaster of Paris

After you have freed your model from the casting material, it's time to fill it with Plaster of Paris. You can make your own at home with warm water and a lot of flour mixed in. I haven't had great results with the homemade kind, but I also admit that I haven't worked with it much either.

  1. Mix the plaster with water until it flows but doesn't pour. The texture should be like a thick gravy.
  2. Start out by pouring enough plaster into the molding to cover all surfaces. Roll the plaster around, so it dips into every nook and cranny. Then, fill the mold the rest of the way up. Tap the molding to encourage bubbles to rise out of it.
  3. Set aside to dry.
My apple looked more like a strawberry to me, so I went with it!

My apple looked more like a strawberry to me, so I went with it!

Step 6: Decorate It and Have Fun!

Once the plaster is solid, you can paint it or decorate it in any fashion you like. The possibilities really are endless! I hope you try creating your own fun projects with this mold-casting tutorial!