Are moulds the easy way out? - Sophi Sherwin Suttor
There are many ways of making pots. They range from thrown to hand built and everything in between. There is a hierarchy of respect attributed to making skills. Perhaps at the bottom end is ceramics made by using moulds. Many people who haven’t used moulds think using a mould needs no skills especially if the mould is purchased from a catalogue or off the shelf. Custom moulds attract a higher level of respect as they are thought to engage the potter at a higher level.
Moulds can be one piece producing ’flatbacks’. moulds can have one or more pieces. They often don’t have seam marks.
Most pots come out with seam marks that need to be cleaned off. This requires patience, an eye for detail and sensitive persistence.
Initially cutting back seam mark with a potter’s knife
Wiping with a damp sponge and a
final reduction with a sable like brush and water.
There are many other techniques, suggestions welcome
The clay may break at anytime when using these methods and you must start again. Reclaiming slip is very time consuming. It can alter its chemical composition and make it unusable.
Every mould is unique. Repeated use will show how each mould likes to be treated such as more time or less time and many other variables.
Where to start
I buy new and second-hand moulds. I look for the moulds to be in good condition. I like moulds where the joins are in easy to clean places like the edge of a plate and are quick to clean. I assemble the mould. I place bands on the mould. This is essential. I favour large elastic bands. These are expensive. I also like bands cut from tyre inner tubes cheap and effective. One day I hope to have every mould fitted with their own bands. I don’t like the woven straps because I can’t seem to get them tight enough. I am waiting for someone to invent straps made from elastic and Velcro.
Multi-piece mould showing use of bands made from inner tubes and a mold showing use of commercially available rubber band
Not enough bands or poorly place bands may allow the mould to split open and empty slip onto the floor/table. What a mess. I do a lot of pouring with the mould in one of those soft plastic baskets like buckets found in hardware or gardening shops. You can save the pot by quickly pushing the mould back together, adding bands and adding more slip to the mould Best to have two people working together on this or any large mould particularly if the mould stands vertically to be.
I make a lot of slip cast pottery I use rubber bands to hold the molds together. I get some persistent leakage from some isolated places of the molds. This is a waste and makes a lot of mess. I have found a solution. After I put the mold pieces together and before pouring slip I paint the outside joints with slip WHERE THE LEAKS ARE. This seals the leaking joint and stops leaks. In time you will know the places where the leaks are. This makes it easier and neater and reduces leaking to almost nil.
5 Litre bottle of slip
I work with Walkers white earthenware slip. I buy it in the 5 litre bottle because I can manage it. I am in a wheelchair. I make a lot of choices so I can go on potting. When I get the slip home, I sieve it at 800 mesh This cleans out any foreign bodies. I add about ½ cup of water to make it the right consistency for my practice. Be careful adding water as it can undo the the properties of slip. Sieving the slip gives it a beautiful creamy consistency
I return the slip to the five litre bottle using a funnel. I write a number on the bottle, so I know which one I am using. I am very good at making a giant mess with slip. I work at confining the slip. I use big funnels for slip transfers from bucket to bottles and back. I use a jug to pour moulds I buy the jugs from a teashop. They have a big capacity. They have a screw down lid. This means you can seal the jug and go and do something else. The slip remains active and it is easy to shake the jug for the slip to be the right consistency
Jugs used for pouring slip
I measure the time the slip is in the mould. At first, I start on 20 min. I adjust up and down until I get the right thickness of clay lining the mold. I then write this time on the mould. I also write the name of the mould. It helps to find them quickly. The more you pour a mould in quick succession the longer the slip needs to sit in the mould as the plaster absorbs more and more water as it becomes less efficient.
After your preferred time has elapsed you empty the moulds. Here is where you must make some choices. Used slip can be disposed of thoughtfully or into reclaiming. Used slip can go into a bottle of its own with the name written on the bottle. Or it can go back in the bottle with the unused slip. Each choice has consequences. Time and experiments will dictate your choices. After you have poured the excess slip out of the mould leave the mould for2 hours for the slip to become leather hard. If the mould is hard to separate it is not ready to open.
I have made slip from scratch starting with a big bag of powdered slip and a plastic garbage bin. You need to carefully measure all the ingredients. This can get very technical. I mix with an electric blunger. My capacity to make a mess increases dramatically.
Here are the instructions to mix your own slip
So, weighing up all the variables I buy my slip in 5 litre bottles. I have just started to buy 10 litre buckets. In the past I couldn’t get the lid off. I talked it over with the manufacturer. He changed the lids. I can get them off now.
In my situation I have an assistant. It makes life a lot easier and mess a lot less
Items made in my moulds are forever changed by alteration, addition, use of decals, cutting and pasting etc. This is done in the eternal search for new and profound meaning. It is this part of the process that deserves more respect in the ceramic world
So are moulds the easy way out in ceramics?
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