Pottery Glazing Techniques
Glazing is an important step in creating a finished piece of pottery. The traditional glazing techniques are dipping, pouring, or brushing. You will find that these three techniques will serve most of your glazing needs.
Preparing to glaze
Before any glaze hits your pottery, there are a few things you need to consider, and some prep work you need to do before starting.
The first thing to consider is your choice of clay and glazes. When choosing your glaze, make sure it’s compatible with your clay to prevent crazing (spider-web cracks in the glaze), bubbling (places where the glaze bubbles up), pinholes (tiny holes through the glaze), and even cracking. For best results, make sure the firing temperature range of your clay matches the fire temperature range of your glaze (for instance, use a mid-range glaze with a mid-range clay). That said, you may find over time that some clays and glazes just don’t get along. It’s best to test-fire your clay and glaze before you glaze large batches of pottery.
With the exception of underglazes, you should apply glazes to bisqueware (pottery that has been fired to cone 08 to 06) You should always clean bisqueware before glazing, because glaze adheres best to clean, dry pottery. A damp sponge works great, and your pottery will dry quickly—don't submerge your pottery in water or rinse it off under running water. Allow it to dry before beginning to glaze.
It is important that the bottom of each piece be glaze-free, because any glaze on the bottom of the piece will melt in the kiln and fuse your piece to the shelf. After you have finished glazing it is important to check the bottom of each piece. If there is any glaze, use a damp sponge to wipe it off. A layer of wax resist can be applied prior to glazing to reduce the amount of glaze that sticks to your piece. Even if you have applied wax resist, however, you should still check the bottoms for residual glaze.
Mixing your glaze
Whether you’re dipping, pouring, or brushing, you have to mix your glaze. Even though bottle glazes are more stable (and pre-mixed), mixing your glaze often is still a good habit to get into and ensures a nice even layer of glaze. Glazes in pint or smaller containers can be shaken in the container to mix. For glazes stored in 1-to-5-gallon buckets, an electric drill with a mixer attached works best.
When mixing glazes, it is important to pay attention to the consistency of the glaze. Glazes should be a “skim milk” consistency, in other words, quite thin. You may need to add a bit of water to your glaze if it seems thick when you take it out of the container or if water has evaporated out of a large bucket. Having a tight-fitting lid on your container of glaze will help reduce evaporation.
If you're preparing your glaze from a dry glaze rather than using a pre-mixed glaze, check out this tutorial on mixing dry glaze.
You will want to glaze the inside of your pottery first. If you glaze the outside first, your chances of leaving marks and messing up the outside of your piece will go way up. To glaze the inside of a piece, pour the glaze into the internal area and rotate the piece to cover the entire interior. Pour the remaining glaze back into your container. Allow the piece to dry before moving on to the outside. You'll be able to tell it's dry when the glaze no longer has any shine.
Brushing on glaze
Brushing is the most common method for applying glaze to small items, and for creating detailed designs on larger pieces.
When brushing on glaze, you should have a nice soft brush that can hold a good amount of glaze. Hake and sumi brushes hold the extra glaze that is needed to cover pottery more evenly. Fan brushes also have the ability to cover large areas smoothly and evenly.
It is also a good idea to have two bowls with water and sponges in them. The sponges help get the glaze off your brush. Always use the first bowl for initial cleaning, then the second cleaning bowl as a rinse.
When brushing on glaze, it is important to apply three coats of glaze and alternate the direction of your brush strokes with each coat. For instance, your first coat can be horizontal and your second diagonal, and the third vertical. Applying three coats in this way will even out the thickness of the glaze and helps to get rid of streak marks.
Make sure your glaze is dry between applying each coat. The more layers you apply, the longer you’ll have to wait before applying another coat. Don’t take a chance and hurry the process. You will be able to tell that the glaze is dry when it loses all its sheen.
How to pour glaze
If you choose to pour your glaze rather than brush it on, use a container with a pour spout (like a pitcher), or use a ladle, for better control of the glaze as you pour. You should pour the glaze onto the piece over a large container to catch the glaze that runs off your piece. If your glaze is on the runny side, pour the glaze with your piece upside down, as more glaze will therefore build up at the top of your piece (the side facing down while you pour). Excessive glaze at the bottom of a piece risks it sticking to the kiln shelf.
Turn your piece as you pour to completely cover the desired surface. You will only need to pour on one layer of glaze to get even coverage. If a glaze drips on an area that has already been glazed, or if there is too much glaze in one spot, resist the temptation to wipe it off while it's wet. Any extra glaze on your pottery is best-taken care of after the glaze is dry. If the glaze is still wet when you try to remove it, you will most likely remove too much or smug it, and it will show in your finished product.
After your glaze is completely dry, you can use a clean-up tool, metal rib, or sandpaper to carefully remove any extra glaze. (When scraping or sanding dry glaze dust is created. Don’t forget to wear your dust mask.) How to dip glaze your pottery
How to dip glaze your pottery
Dipping is a common technique when you're glazing large numbers of pieces with one or two glazes, or if you want a solid coating of glaze to add decoration to. If you’re planning to keep some parts free from glaze, such as the bottom, or design elements that you want to emphasize, brush on wax resist to create a protective coat.
After you have mixed your glaze well, you want to get all the little bubbles out before you dip your pottery in the glaze; slowly stirring your glaze will help prevent bubbles.
Use tongs to dip your pottery in the glaze, making sure you place them in the most solid and secure area of your pottery. Be sure to clamp down firmly but gently with the tongs, since you don’t want to crack (or even break) your piece. When dipping, place it in the glaze container carefully—like a ladle or soup spoon—while being careful not to hit the sides. The amount of time you hold your piece under the glaze will dictate the thickness of the glaze. It is recommended to count to three before pulling the piece out and shaking off the excess. You may need to adjust this time to achieve your desired result.
When starting out on your glazing journey, it can seem a bit daunting or tricky to master. But by following these glazing tips and practicing (and testing!) your glazing skills will definitely improve and your success rate will go up.