One thing that makes your pottery piece stand out from the rest is a unique painting or design added on top. Now, adding colors to your molded pottery isn’t a straight road. You need to first understand the ways you can paint them in order to avoid any mistakes. The first method is glazing, while the second is painting with colors such as acrylics or oil paint.
Regardless of the method you use, painting a pottery piece can be tricky if you lack the experience and appropriate information. In most cases, especially when using ceramic wares, potters use the glazing method to achieve impeccable results during the painting process.
So, let us take a look at the mistakes that can occur during the pottery painting process. But, before we do that, let us understand more about the types of glazes available for use.
Pottery Painting: Types of Glazes
1. Earthenware Glazes (Lead-Free):
If you plan on using your pottery for eating or drinking, it is better to glaze it with the earthenware glaze that is free of lead and packs in a range of colors & special effects that tend to all your requirements. It might contain a trace amount of lead which is completely safe for use in your utensils and dinner-wares. A popular lead-free option you can try is the AMACO glaze set that contains 6 beautiful colors. The glaze can be used for more than 12 months and gives you bold and accurate prints on the pottery piece.
2. Earthenware Glaze with Fritted Lead:
This particular glaze variant consists of a good amount of red and/or white lead. So, it is most definitely toxic when used for preparing dinnerware. It is mostly used for decorative purposes in flower vases. Some variants of this glaze come with a mix of lead-based bi-silicate frit that is melted together during the firing process to make sure it is insoluble & acid attack resistant.
3. Mid-Fire or Stoneware Glazes:
The Mid-Fire or Stoneware Glazes are constant in reducing and dissolving conditions. This helps produce multiple color variations when mixed in with different stippled and colored bodies. In addition, all these glazes can be mixed with each other while allowing double-dipping, pouring, mottling, or painting with different colors under or over the glaze.
4. Raku Glazes:
It is a specific glaze variant that is traditionally used for Japanese pottery painting. These glazes are perfect to be fired at specifically low temperatures, thus creating some unique designs that aren’t possible with high-fire glazes.
Safe for Food/Drink
|Earthenware Glaze (Lead-Free)||Yes||950 to 1150o Celsius|
|Earthenware Glaze (Fritted Lead)||Yes||950 to 1150o Celsius|
|Mid-fire/Stoneware Glazes||No||1280 to 1300o Celsius|
|Raku Glazes||No||800 to 1000o Celsius|
Apart from this, you can use normal colors to create beautiful patterns on your pottery pieces, especially if you plan on painting on air-dry clay. Acrylic colors are the best when it comes to painting air-dry clay. It holds up best when compared to similar paint variants such as Tempera. Apart from being durable enough, this color is also pocket-friendly. Acrylic paint generally is water-resistant and can provide your air-dry clay with the best waterproof sealing. These colors are thicker, can be diluted with water, and are available in several bright colors. Apart from this, you can also use oil paint to color your air-dry clay. However, it might not be as good as acrylic in terms of results. Plus, it might also be too expensive as compared to acrylic clay.
Now that we have explained the basics, let us take a look at the 3 mistakes you might make when painting your pottery with glaze.
Mistakes to Avoid When Painting Your Pottery
1. Not Understanding Crazing & Shivering Issues:
These two mistakes go side-by-side when it comes to painting your pottery with a glaze. Let us take a look at the first one: Crazing. It is undoubtedly a major mistake and can render your pottery piece unusable with all that effort gone to waste. However, although it is a major mistake, it can be corrected with ease.
Ever seen a dried-up paste? You can see some cracks forming on the surface. This happens as the moisture from the paste starts to evaporate at a very fast rate than normal. It is the same observation that you can see with the crazing issue. But why does crazing happen to your pottery work? If you happen to notice patterned cracks in your craft item, it is most definitely crazing. You can easily detect this issue by breathing onto your piece in order to glaze the piece’s surface.
Crazing is actually the discrepancy that happens between the expansion coefficient of your chosen glaze and the clay body. Whenever the glaze expands more as compared to your clay body, it leads to crazing issues. This problem can easily be corrected by selecting the right glaze for the project. You need to reduce the glaze expansion for it to match that of the clay body. Alternatively, you can switch to a clay body that has a higher expansion ratio. If you cannot change the glaze or the clay body, you can opt to add expansion materials to the glazing mix. This could include options like silica. It helps with a drastic reduction of the expansion in the glaze.
On the other hand, shivering is a similar form of glazing error that happens due to the interaction between glazes with a lower expansion rate as compared to the clay type being used by you. However, it could be a bit complex as compared to crazing. This particular problem occurs when the glaze shivers. The problem is denoted by cracks & pieces of the glaze peeling right off your pottery piece. It is often prevalent on the project’s edges.
It is a major issue as the glaze slivers can start to peel off from your pottery’s edges and might even mix into the drink or food in case you use it for kitchen needs. This can be particularly toxic in case the glaze consists of a mix of red/white lead. In this case, the glaze’s expansion ratio is lower than that of the clay.
The best and most opted solution, in this case, is to enhance the glaze expansion rate by mixing it with materials that aid the same. Alternatively, you can switch to clay with low expansion. While you add silica in the former issue, the latter requires you to reduce silica from the glaze mix. Alternatively, you can also increase the nepheline syenite or sodium feldspar amount in the glaze. Other alkaline-containing materials can also help you avoid shivering issues. In both cases, proper balance is the key; too much or too little and you can end up destroying the beauty of the pottery work.
2. Crawling Issues:
If you are a beginner, you must have observed this issue for quite some time. However, it might happen even with the most experienced potters. Crawling is a common ceramic glazing issue that surfaces during the firing of your pottery ware. As crawling happens, it can leave bare patches throughout the body, and the glaze starts to separate into islands and clumps.
The issue is mostly caused when the glaze shrinks a lot as it dries out and eventually starts to crack. These cracks start to become the prime crawl points in the firing process. It happens due to excessive shrinkage that occurs due to the presence of a lot of raw clay mixed into the glaze. This can also happen if the glaze layer is applied way too thick on the ceramic.
Multi-layering in an inappropriate manner could also be a prime cause of the crawling issue. Multi-layering the glaze tends to rewet the initial layer, thus stressing the bond with your clay body. Eventually, it pulls it away during firing from the clay and hence causes the crawling problem.
In simple words, it can happen due to the use of glaze that is excessively powdery with minimal moisture content. Additionally, if you fail to allow the underglaze on your clay to dry properly before applying the next layer, it can cause crawling.
Clay doesn’t flow the right way when you make the glaze too thick or too thin. It tends to accumulate in one place while being thin in another. At times, crawling happens due to adhesion issues that are caused due to bad glaze application. The powdery glaze doesn’t attach well to the clay surface and makes crawling an avoidable issue.
It is also a problem that is faced by potters that use powdery or matte glaze as compared to liquid glaze. You can also experience crawling if one glaze type is applied to another. Always ensure that your under-glaze has enough moisture before applying the over-glaze to ensure they adhere to each other.
3. Blisters and Pin-Holing:
Just like shivering and crazing, blisters and pin-holing are the exact opposite of each other. So, let us talk about blisters first. It is often an issue that forms due to excessive glaze application or incomplete preparation of clay. If you have ever seen the pictures of the moon craters, these blisters look similar. These craters are generally 0.5cm or less in diameter. Professional potters mention that insufficiently dried glazed pottery piece tends to create a population of blisters.
Apart from this, you can also expect your pottery work to have blisters in case air has been trapped beneath the glaze during the glazing process. However, these aren’t the only reasons that cause blisters in your artwork. The clay variant used by you can also be responsible for the formation of blisters. For example, a clay body that is too dense can trap air within the piece and hence cause blisters.
Additionally, fluxes such as boric acid, sodium carbonate, potassium carbonate, borax, and magnesium sulfate can be responsible for blistering. If your glaze has these fluxes, you can replace them with better options in the market or add some fritted materials.
Now, let us discuss the pin-holing issue. Also known as pitting, it is an annoying problem that can irk even the best pottery artists. It is mostly caused due to an ill-controlled firing process. Along the lines, it could also be caused due to the glaze’s composition or your choice of the clay body. As per reports and information provided by several potters, highly grogged variants of clay can also lead to the pin-holing issue. So, if you ever see dots or tiny holes in your clay body, you can confirm that it is a pin-holing issue. To ensure that it doesn’t make your artwork look ugly, you need to ensure that the firing cycle is longer & the glaze is applied in a less thick manner.
What are the benefits of painting or glazing your pottery work?
Glazing or painting at times isn’t simply for the purpose of decoration. It can do much more than that. Depending on the glaze you choose, the value of your artwork can spike up when fired the right way.
1. Keeps it Waterproof:
With the right glaze used on your pottery piece, your artwork becomes waterproof and can be used for holding food, water, and practically anything in your kitchen. If you use it outdoors, it can also keep it protected from the moisture present in the environment. When using for food and water, make sure you use lead-free glaze.
2. Helps Toughen Up the Surface:
Apart from making the clay body waterproof, the glaze can also make your pottery work tough from the exterior. It acts as a barrier that reduces any impact on the vessel.
Now that you know the mistakes that potters can make when painting the pottery work, you can stay away from them and create amazing pieces. If using your pottery work as dinnerware, make sure you choose a glaze that doesn’t contain lead. Invest in a safe and colorful glaze that makes your pottery piece look amazing with few simple coats.