We are all crossing our fingers that this show will be able to go ahead. If you are in the Grafton area on June 5th & 6th, it would be lovely to see you.
10821 County Road, Grafton.
Part 2 on Casting a 3 Part 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.
You can purchase straps to hold your mold together, or in this case, inner tube rubber, cut into strips.
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.
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 as well as how thick/thin your slip is.
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.
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.
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.
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.
And there you have it, the end result, bisque fired and ready to glaze.
Here are some images and basic instructions on how to tackle a 3 part plaster mold for doing slip cast pottery. I created this way back in 2014 and posted to a guild that I belonged to, but I thought it would be good on my own site! My own original sculpture and work.
As for the spelling. Both are correct, sort of. It is mould in the UK and mold in the U.S. We usually default to the British spelling for many words, but I’m not sure in this case. So I’ve spelled it mould in the title of this article but mold throughout the post. I lived for 14 years in the UK, so I’m often thoroughly confused as how to spell anything or even what country I am living in.
Thank you to Angelo diPetta for his advice on how to cast this piece.
Always measure using cm. L x W x H for a rectangular volume or Pi x r squared x H for a cylindrical volume – always use centimetres. This is the required plaster mix. Multiply the number by .6 in order to get amount of water required.
Example: 30cm x 20cm x 10cm = 6000 cubic cm or 6 litres of plaster mix, then 6000cc x .6 = 3600cc or 3.6 litres of water. You could also multiply 6 litres by .6 and get 3.6 litres. This works because 1cc = 1ml. Depending on how much the model displaces the plaster you will have little or more plaster remaining.
To see an article explaining cottle boards, visit Ceramic Arts Daily. They have a video about how they work and how to make adjustable cottles. These ones are made of recycled plastic of some sort. But you can use wood as well with equal results. Just be sure to seal the sides with mold soap concentrate so your plaster doesn’t stick to the boards and to make them easier to clean afterwards.
In this particular sculpture, the part that will be cut out for the entrance to the vase is lower than the highest part of the piece (i.e. the inside of the fist of the hand), so it was decided to make the pour spout at the bottom. After the piece is cast, this can be filled in. The part that is coming out of the hand is for the third piece of the mould.
Mix your plaster and pour it carefully into the cottle. Let the plaster set up and then you can remove the boards, turn over the piece ready to do the second part of the mold.
I’ve used vaseline or Murphy’s oil soap to create a resist between the two pieces, but it is best to get mold soap from a sculpture or ceramic supplier. You paint a few coats on and let it dry and then clean it off so the surface is nice and smooth. You know you’ve done enough when it buffs up shiny and water beads on it when dropped. Otherwise you will have a lovely solid piece of plaster, but won’t be able to get it apart.
Be careful not to get any into the inside of the cast, as you need the clay to be absorbed in that part.
There is no image of making the final piece of the mold, but keep the two pieces you have already cast together, and remove the block of clay that was blocking off the last section. Clean as you did for the first casting and make a deep score between the two pieces to create another register. Coat the plaster again with the mold soap and when ready, pour your plaster into the last section. Let it set.
Clean up the edges of the mold. Clean the sides as well, as it will often help you see the seam between the parts you have cast.
If you have a rubber mallet, tap the mold all over – this helps loosen the pieces. Then tap the stiff blade of a knife into the seem, and pry – do this all around the seem line. Sometimes the suction of the clay makes the pulling apart a bit harder. Be careful though, you don’t want to ruin the cast.
What you should do now is round the corners of the mold and clean it up. This way you don’t have jagged edges that can chip off, and it keeps it neater. Put the mold in a warm, dry area for a few days until it is no longer damp and cold. This mold took 4 days of sitting near a register.
I’m thrilled to be taking part in this outdoor Christmas market this year. It takes place at Sandy Cogar’s studio and will have all sorts of different art work. Sandy’s metal sculptures, pottery from a few people, hockey stick art. Lots of fun stuff. Get original Christmas art direct from the artists.
It’s been a crazy time for everyone. I’ve had my head down in my day job and working on ceramics during the evening. I’ve got lots of different themes for this year and I can’t wait to show them off at the Victoria County Studio Tour the 26th-27th September and again on October 3-4.
I was going to try a few new shows and not put my art in a few other venues. Sadly, the two shows in Little Britain and Picton have been cancelled. I’m hoping that the Victoria County Studio Tour at the end of September, and the Marshland Centre in Lakefield in November will go ahead.
When we are able to see art again and life is a little back to normal, if you can afford it, support an artist by buying their work. Even a little piece will make them happy and help their income.
See you soon!
I will be showing my work in Lakefield on the weekend of November 16 & 17th from 10 – 4pm.. This is a lovely show in a scenic location in Lakefield. It is boutique style, meaning that all of the artisan’s work is spread around the venue, artfully displayed. This year is the 14th annual Christmas show, featuring the work of local and regional artisans.
It takes place at:
64 Hague Blvd, Lakefield.
I’ll be participating in the Artisanity show and Sale on November 1 – 3 in Peterborough. This show includes many artisan crafts such as paintings, wood turning, pottery, gourd art, scarves, ornaments, stuffed animals, jewellery, quilts, felted items and much, much more. Free Admission, it is a fundraising show for the Artisan Centre, Peterborough.
Takes place at:
Knight of Columbus Hall,
317 Hunter Street,
Hunter St. & Rubidge St.
I had a friend, the talented Kathryn Frank, take some photos of my platters for me, and I’m thrilled with the results. Here is one to start with. Running bunny.