Also known as Stack and Slam Wedging, Slam Wedging clay is an excellent technique to create a smooth, consistent and air-bubble free clay body for your pottery.
Why is it important to wedge clay?
It is extremely important to thoroughly wedge your clay prior to beginning throwing it on the wheel. There are many reasons for this.
1. It creates a smooth consistency in your clay body.
If you skip the wedging phase, it is likely your clay body will have hard and soft areas throughout. When you go to throw with clay that has an inconsistent clay body, this almost guarantees that your form will be off center. The reason for this is because when you are pulling up your walls with equal force all the way up the wall, areas that are softer will be impacted more than areas that are harder, even if your pressure is the same.
2. It eliminates air bubbles
Unless you have pulled clay fresh from a pug mill, it is very likely your clay will have air bubbles.
Air bubbles are created when different pieces of clay are added together, and air gets trapped in between them. Similar to creating a consistent clay body, if your clay has air bubbles, this increases the probability that your piece will become off center in the throwing process.
If air bubbles are not discovered and popped, it will be more difficult to effectively deal with them once you have opened up a cavity in your piece. Air bubbles trapped in the walls of your pot tend to feel harder than the soft clay surrounding them. Thus, when you go to pull up your walls, that air bubble will stay stiff instead of moving from the force of your pull. This will create an asymmetrical height on the rim of your piece and uneven wall thickness around the circumference of your pot.
Benefits of Slam Wedging
Slam wedging is my favorite wedging technique over Ram’s Head Wedging and Spiral wedging. The reasons for this are:
1. Slam wedging is better for your wrists
Because slam wedging doesn’t require the same repetitive pressure directly on your wrists, this method is more ergonomic.
Frequent repetitive grasping motions in your hands paired with downward pressure on your wrists dramatically increases the likelihood of joint and muscle injuries.
2. You can wedge clays with different dryness levels
When I am reclaiming clay and I leave sopping wet clay out to dry, I leave it for too long and it becomes stiff as a board. Every. Single, Time. This is exactly what I don’t want to do when I am reclaiming clay. Avoiding working with hard clay is better for my hands and wrists and also way easier to manipulate on the wheel.
When this happens to me, instead of trying to rehydrate the stiff, dry clay yet again, I will slam wedge the stiff clay with a much softer clay. This is great because I can take 2 undesirable clay bodies, one that is too wet and one that is too dry, and combine them together to create a smooth and soft clay.
If I was to try this with ram’s head wedging or spiral wedging, it would be difficult to integrate the soft clay into the harder clay without the softer clay squirting out. It would also be hard on my wrists in the beginning of the wedging process while I am doing the repetitive wedging motion on hard clay.
3. You can wedge larger amount of clay with Slam Wedging
Because slam wedging is relying more on your arm and core strength that the strength and pressure in your hands and wrists, you can wedge more clay at a time. Ensure you are lifting the clay off the table (Step 4) with your arm and core strength rather than lifting with your back. This will help prevent any back injuries.
Also, do not try to wedge too much. Although I find I can wedge more clay when slam wedging, it is still important to recognize limits.
How to Slam Wedge
1. Cut the piece(s) of clay that you want to wedge into slices, so you have a bunch of flat pancakes on your wedging board.
2. Layer the pancakes, alternating between the different clays, until all of your clay pancakes are layered together.
3. Pick up your new layered clay chunk so that the layers are parallel to your wedging table and SLAM the clay chunk directly downward.
4. Pick up your, now slightly flatter, clay chunk from the table. Flip the chunk over on its head, keeping the layers parallel to the wedging table but now slamming down on the opposite side.
Repeat this slamming 4-6 times, alternatively the side you are slamming down onto (so 3 slams per side)
6. Once you’ve gotten your frustration out 4-6 times, Cut your chunk in half, vertically
7. Place one half of the chunk on top of the other side so that all layers are still parallel to the wedging table (horizontal).
You want to ensure you are keeping the orientation of the layers consistent. This ensure that as you are wedging, your layers are multiplying and getting thinner each time. Picture integrating butter in a puff pastry to make croissants. Once it is done, you have hundreds of paper-thin layers.
8. Repeat this process of slamming your clay down 4-6 times, slicing in half and repeating about 10 times.
9. You will know you’re finished when you see the clay body is now consistent and there are no air bubbles in between the layers of clay.
10. Finish the process by dividing your clay into balls of your desired size.
I’ve learned the hard way that skipping the wedging step will come back to bite you. Putting the time in up front to ensure your clay is properly wedged will make the throwing process much more enjoyable and successful.
If you have success with your slam wedging or have a question, leave a comment below and I’ll be sure to get back to you!
Sources
https://www.hopkinsmedicine.org/health/conditions-and-diseases/carpal-tunnel-syndrome
