To Teach, To Learn, To Share

Casting from a Plaster Mold

After the mold is cleaned and left to dry for a few days to a week, it is time to make your first cast.

This mold is held together by inner tube rubber, cut into pieces
This mold is held together by inner tube rubber, cut into pieces
Pour the liquid slip carefully into the mold up to the top.
Pour the liquid slip carefully into the mold up to the top.

You should put on a timer for about 15 minutes at first, keeping a look out for the level of the slip. As the water is absorbed into the plaster, the level of slip will go down.

Top up the slip as the moisture is absorbed
Top up the slip as the moisture is absorbed

You will want to experiment on the timing, but for this casting, 30 minutes is about right to cast a piece.  However, this could change depending on how many pieces you cast and how damp the mold gets.

When you feel that the casting is thick enough, pour half of the slip back into the container and then swirl the remainder of the slip around the casting for a few minutes before pouring it out.

Place the mold onto an elevated prop to allow the remainder of the slip to drip out.

The mold will now take an additional time to dry enough to remove the piece from the mold.  In this case it is 30 minutes of drying time.

Clean the spout hole, being careful to not let the trimmed pieces fall into the sculpture.
Clean the spout hole, being careful to not let the trimmed pieces fall into the sculpture.

When dry and ready to remove the piece, clean the spout hole.

Take the bindings off from the cast and carefully pull the two pieces apart.

One side of the cast has been removed, if the piece is dry enough, carefully pull the sculpture out from the second part of the mold
One side of the cast has been removed, if the piece is dry enough, carefully pull the sculpture out from the second part of the mold

In this sculpture, the third piece can now be removed as well.

As the pour spout is located at the bottom of the sculpture, we now have to close that opening.

Pour a bit of liquid slip onto a flat plaster bat and place the sculpture on top.  This will quickly adhere to the sculpture and create a smooth bottom.

Trim the opening.
Trim the opening.

Your sculpture will have seams that can now be cleaned up and you can cut out the opening to the vase, again being careful not to allow the piece to fall into the sculpture.

bisque-fired
ten castings coming out of the bisque kiln.

And there you have it, the end result, bisque fired and ready to glaze.

June Goodwin getting ready for show

June Goodwin is the hardest working member of our guild.  A lot of days you will find her at the gallery, either teaching or doing our books, as she is our treasurer and general “go to” person.  How she has time to do her own work is beyond us all!  Below is some of her work that has been bisqued and is ready to be glazed.  That is where the magic comes!  Every time we open the kiln, we never know what we will get!  You’ll have to come to our sale to find out!

Click on the image to see a larger version.  The work below includes not only June’s pottery, but our member Barb Zmozynski on our “Newbie” table!

Do NOT follow this link or you will be banned from the site!