How to Make a Plaster Bat

Video Version:


I make my own clay, so I needed to make a plaster bat to help me out with the drying process since it’s great at absorbing water. In this ‘how-to’ I will share with you an easy method of making you own. The main principles of the method can be used for all kinds of plaster casting.

Step 1: Greasing the Mold

Find a suitable mold that will give you the shape you want- a large plastic flower pot bottom is perfect for this. Begin by rubbing vaseline all over it to act as a mold release- you don’t need to put too much just enough to coat it and make sure to get the sides!

Rubbing vaseline on the mold

Step 2: Filling a Container With Water

When mixing plaster its important to put it into the water and not the other way round- you can eyeball how much water you would need and pour it into an empty container. Hot water will make the plaster set faster whilst cold water will take longer- so I recommend using cold water so as to have a longer working time.

Step 3: Adding the Plaster

Add the plaster to the water in handfuls by sprinkling it evenly over the surface. I keep repeating this step until little ‘peaks’ or ‘plaster islands’ start forming.

Sprinkling handfuls of plaster over the water surface

Step 4: Getting the Plaster is Ready

When the plaster starts reaching the top of the water and creates a ‘dry earth’ cracking effect, it is ready to be mixed.

The plaster creating a ‘dry earth’ effect

Step 5: Mixing 

I like to mix the plaster using my hands- rubbing it between my fingers to break up any clumps and to homogenize the mixture. I feel like this reduces the amount of bubbles that will be created.

Mixing the plaster

Step 6 : Pouring 

Pouring the plaster into the mold

When the plaster feels sufficiently mixed its ready to be poured into the greased mold.

Step 7: Releasing Air Bubbles

After pouring the plaster I shook the mold a little bit so as to create a nice even surface and I then tapped it to release air bubbles -  if this was for a sculpture or a precious project I would tap for much longer. Now leave the casting to cure and dry for a few hours till its ready for de-molding!

Poured and tapped plaster

Step 8- De-molding

To de-mold just flip the casting over a soft cloth ( I’m using a a soft door mat ) and with one tap the casting comes right out!

De-molding

Step 9: Drying and Shaping (Optional)

After curing, leave the plaster bat to dry completely. This can take from a week all the way to two weeks depending on the weather. You can also hit the edges with a rasp but this is totally optional.


Softening the edges of the plaster bat

At this point the plaster bat is totally ready for use!

Materials Used:

US: 

Ceramic Plaster (important): http://amzn.to/2xnTL2b 

Vaseline: http://amzn.to/2gVc3wY 

 UK

Ceramic Plaster (important): http://amzn.to/2xnTL2b 

Vaseline: http://amzn.to/2jfxOMs

Using Format