Handbuilding pottery basics: Making Slip and Joining Pieces

1. Introduction: I'll take you through how to join separate pieces of clay by making and using your own slip. Slip is essential in hand building. It's also referred to as slurry. It's the glue that ensures that the joins between two separate pieces of clay are strong and they won't come apart as they dry or when they are fired. Slip is very easy to create, and all you need is clay and some water. You do need to make sure that the slip you are using matches the clay for you're using for your project. Once your slip is made, you're ready to start joining pieces of clay together. I'll take you through the method to create strong joins to ensure your pieces stay together when dry and as they are fired. 2. Making Slip: Making slip is very easy, but it does take a little patience. So it's best to prepare it before you start your pottery project. To begin, we'll need some dry scraps of clay. You always want to be using slip made from the same clay as your project. A different clays have different properties and trim rates. To start, tear off a small piece of the same clay that you're using for your project and let it air dry completely in an open container. Once it's dry, add a small amount of water and leave it to sit for a while until the clay has dissolved fully into the water and then mash the clay into a smooth paste. The consistency should be slightly runnier than toothpaste. Think runny, honey. Start with a small amount of water. You can always add more if you need it later. For extra smoothness, you can add a small amount of vinegar to the mixture. This helps break down the clay and creates a smoother consistency. It also improves adhesion between the pieces and can help prevent mold. For an extra smooth slip, you can use a stick blender to create a really creamy consistency. Once it's the desired consistency, store your slip in a sealed container when not in use and make sure that you label it with the type of clay that you used. I like to keep two containers for each of the clay bodies that I'm using. One has the slip ready to go in it, and the other has little scraps of clay from trimming pieces in it. And I leave this container drying out so that I have dry scraps of clay ready to go when I need to make more sly. 3. Joining Pieces: Learning how to make strong joins is essential to the success of your hen build pottery. Strong joins mean that your pieces will be more likely to survive the stress of drying and firing, as well as in daily use. The key to joining different pieces of clay together is to make sure they are of similar dampless level as possible. Clay that is bone dry won't be able to be joined to soft or leather hard clay. If you're joining two pieces of very wet clay together, like clay straight out of the bag, you can skip the slip. And while not essential, I still like to score pieces like this before joining together to make sure they have a really strong bond. To join pieces that are cheddar hard or leather hard, we need to score or scratch and slip the pieces before sticking them together in order to make sure the join is strong. Scoring creates tiny grooves, increasing the surface area for a stronger bond with slip. Think about it like Velcro. To do this, use the tines of your fork or a scoring tool to score each piece of clay along the area that will be joined together. I generally also like to cut the corresponding edges of my pieces at a 45 degree angle, if possible, as this creates a really nice join and the angle helps to keep the joins together as it has a larger surface area. You can use a tool like this or just a knife held at an angle to do this. Once scored adequately, take a little bit of slip on your finger or a paint brush and coat both pieces of clay in the same place you scored. Then you can take your pieces and gently but firmly press them together. It's a good sign if the slip is leaking out the edges, as it means you have a firm seal inside. I like to give one of the pieces a little wiggle, which I find helps stick them to each other better. They should be joined firmly enough that you can't easily pull them apart. Almost like they've become the same piece of clay. Be careful not to separate them again, though, as the join will need time to firm up to be properly bonded. If you've had some slip, leak out the edges, don't stress. You can use your finger or a clean paint brush to wipe away the excess and make the join look as clean as possible. 4. Shoring up your joins with coils: For functional pieces that need to hold liquid or a lot of weight, like the handle on a cup, I also like to add an extra insurance policy to my joins by adding a small coil of clay to the join. To roll the clay coil, squeeze a ball of clay into a sausage shape. Roll the clay sausage on the table using the whole length of your hand from fingertips to wrist. Spread your fingers outward and move your hand from the middle of the coil outwards. If your coil begins to flatten out, turn one end of the coil in one direction and the other in the other direction. This will create a twist in the coil. Twisting prevents the roll from flattening out. It's a good idea to twist the sausage right at the start before you begin rolling, and then now and again as you roll, pick up the coil and give it enough twist. Once you've rolled out a very thin coil, place it up against the part where your two joins. Preferably, this is on the inside of the piece, so you can't see it. Cut off any excess coil. And then press into the join, making sure you're applying equal pressure on the outside of the piece at the same time. Then press along the whole join before smoothing everything out with a finger or a tool. 5. Conclusion: That's it. Now you're ready to keep going on your pottery journey with the knowledge of how to create strong joins in your pieces under your belt. I suggest leaving your freshly joined pieces under plastic in order to even out the moisture levels and help prevent cracking. If you're interested in pottery templates and tutorials, check out my website, Meg Make dot M or my other Skillshare classes in order to learn more. Make sure to post your project in the project gallery so I can see what you've created or tag me on social media at Mgmake dot M and leave me a review.