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If you have any trouble with your wrists or hands you will probably find wedging clay difficult. I have carpal tunnel in both hands, and I find most wedging techniques impossible. Stack and slam wedging is a godsend for me and makes wedging a possibility. Plus, it’s actually quite enjoyable!
Stack and slam wire wedging involves stacking one block of clay upon another and slicing through both blocks. The sliced blocks are then sandwiched together and slammed on the table a few times to compact them. These are then sliced down the middle again, and the process is repeated.
There are a number of different ways of wedging clay. Stack and slam wire wedging is also referred to as stack and slam wedging. And simply ‘wire wedging’. Whether you are wheel throwing or hand building, wedging your clay is important. And if you have problems with your wrists, stack and slam wedging is a very helpful technique to learn.
You can also check out YouTube for my full step by step video on stack and slam wedging.
Stack and Slam Wedging – Why it’s the Best Way of Wedging Clay
Often when potters work, they will end up with bags and buckets of clay with different consistencies. My workspace is full of different bags of clay. Some of it is soft and mushy and some of it is a bit too dry to use.
Wedging clay together with very different consistencies is difficult. It’s particularly difficult if you are just wedging with your hands. The soft clay tends to squelch out from between the harder clay. Stack and slam wedging makes light work of this and blends clays of different consistencies with ease.
Stack and slam wedging is great for blending different clay bodies. If you have different types of clay, you can mix them together provided they fire at the same temperature.
Stack and slam wire wedging is great for mixing clay bodies for a few reasons. If you want a marbled effect, you can stop short of completely blending the clay.
This method of wire wedging gives you distinct layers in your clay. So it’s good if you want to experiment with agateware.
However, if you want to blend your clay completely, you just carry one wedging until the layers are not visible. Stack and slam wedging is the most efficient way of blending clay and you will be done in no time.
Because you are not pushing the clay around on your wedging table, it is much easier on the wrists. Techniques such as rams head and spiral wedging involve pushing the clay quite hard.
This is fine if your wrists are up to it. But if you have any issues with your hands such as carpal tunnel or arthritis, it’s almost impossible.
Wedging Clay the Stack and Slam Way -Step by Step
There are two ways of wedging clay using the wire wedge method. One employs a handheld wire cutter tool. The other involves a mounted wire. I will describe both, starting with the handheld wire cutter method.
Stack and Slam Wedging With a Hand Held Wire Cutter
Shape your pieces of clay into two blocks of roughly equal size. You can do this by simply dropping the clay onto your wedging table until it is in a block shape.
The blocks don’t need to be exactly the same size. You may want to wedge a scrap of one clay with a larger amount of another. However, it’s a little easier to get started if they are somewhat similar in size.
You can wedge small quantities together. However, stack and slam is also really good for wedging clay of quite large quantities.
Throw one block onto your wedging table. If your wrists are good, you can bring it down quite heavily on the table.
Some potters bring their hands down and smack the clay onto the table with their hands. This is fine if you don’t have wrist issues.
However, if you have problems with your wrists or hands, you can just fling the block at the table.
When you fling it, you let go of the clay before it smacks into the table. This way you are saving your wrists from the impact of the slamming action.
If flinging is too much, you can just drop the clay onto the table.
Then throw the second block of clay on top of the first. So that they are stacked on top of one another.
Pick up the stacked pieces of clay and fling them together onto the table a couple of times. Turn them over between flings so that both sides get a bit of impact.
Slide your wire cutter underneath the stacked blocks and slice through the clay completely.
Separate the two pieces of sliced clay.
Take one-half of the sliced clay and slam it down on the table again. Then slam the second half of the clay on top of the first to create a 4 layered stack.
Using your wire cutter, cut completely through the stacked clay layers again. Repeat the above process by slamming one section of the sliced clay onto the table. And, then slamming the second section on top of the first.
Make sure that when you stack and slam them together that you are aligning them so that the layers go in the same direction. Try to avoid stacking them so that the layers are horizontal in one section of the stack and vertical in the next.
One of the reasons for wedging clay is to align its particles. The clay platelets will be more aligned if the layers are all in parallel. This will make it easier to throw the clay.
As you continue this stack and slam process, the layers will become thinner and thinner as the clay blends together.
I tend to slam the clay on the table a few times between slicing. The reason I do this is to keep the stacked clay square. If I just drop it a couple of times, the stack gets taller and thinner, and harder to work with. By slamming it a few times I can compact it down to a stout block.
Continue the process until there are no visible layers in the clay. Check for air bubbles and any areas of clay that have not been mixed sufficiently. Air bubbles in your clay may contribute to it exploding in the kiln.
It doesn’t take long before the clay is completely mixed. This batch only took about 10 minutes.
Wedging Clay – Stack and Slam Wedging With a Mounted Wire Cutter
An alternative to using a handheld wire cutter is to mount some wire at an angle to your table. This arrangement can speed up the stack and slam wire wedging quite a bit.
The wire is attached to your table at around a 45-degree angle. You can buy a wedging table with a cutting wire already attached. However, it is relatively easy to make one yourself.
With a mounted wire cutter, you simply pull the clay through the wire to slice it in half. The process is then exactly the same as the wedging clay with a handheld wire cutter. The only difference is that you are cutting the clay by drawing it through a mounted wire.
This setup can speed up the wedging process quite a bit. Some potters can pick up quite a head of speed once they get going.
I’d like to have a mounted wedging wire, however, I have a 3-year-old toddler running about. And a tantalizing taut wire waiting to be twanged by little fingers is not the safest arrangement. So, for now, I’m sticking with the handheld option.
Another Way of Wedging Clay with Hand Held Wire:
I’ve also seen potters use another method of wire wedging to mix two batches of soft and hard clay.
This process involves the following steps:
- Using a handheld wire cutter, they cut a slice from one lump of clay. The slice is about 0.5-1 inch thick. The slice is then placed on the wedging table like a slice of bread.
- They then cut a slice of the same thickness from the other lump of clay. This slice is then placed on top of the first one.
- The process is repeated, with slices from one batch being alternated with the other. Until both batches have been sliced up. And the slices of clay are stacked in an alternating pile.
- The potter then slams the stack a few times to compact the slices. The stack is then turned on its side, so the slices are at a 90-degree angle to the table. Like a loaf of sliced bread on its side.
- The slicing process is then repeated. As you cut into the clay you can see the striations, or layers, in the clay. This time, as the potter puts the slices on the table, the alter the direction of the layers. The layers effectively crisscross one another.
- This process is repeated around 3 times. The result is that you have semi-blended clay.
- Whilst this is an effective way of somewhat mixing two batches of clay, the clay is not completely mixed.
- Part of the reason for wedging clay is to start to align the clay platelets1. With this method, the clay particles will still be disorganized because of the resulting crisscross pattern in the clay.
- Also, it’s likely that you will have introduced some air pockets between the slices. Therefore, you will still need to wedge the clay afterward using another method like rams head or spiral wedging.
Wedging Clay – Stack and Slam Wire Wedging for Agateware
If you are blending clay that is two different colors, you can stop wedging before the clay is completely blended. This will give you a marbled effect when you are throwing the clay. This is one of the techniques used for agateware.
Wedging clay is unlikely to become any potter’s favorite part of the day. However, the stack and slam wire wedging method is speedy and efficient. And once, you get into a flow, it can feel quite satisfying. All that slamming is a good way to get your frustrations out. And it’s cheaper than therapy!
- The Potter’s Studio Handbook. By Kirstin Muller.