When you make something out of clay and it has a bisque firing turning it from clay to ceramic, this does make it hard and durable but that doesn’t mean that it is watertight.
There are a few different things to know...
Ceramics holding liquid
- In order to hold liquid in ceramic it needs to be glazed, the reason is that glazing gives a protective layer over the absorbent ceramic material giving it a waterproof coating.
- You can put liquid into a piece of ceramic that hasn’t been glazed but the water will get absorbed into the porous ceramic, this will weaken it overtime and cause it to break.
- Also if ceramic isn’t glazed and you put liquid in it, filaments come out of the clay and will go into the liquid, if you want to use the ceramic to drink or eat out of this is potentially dangerous.
Storing ceramics outdoors
- A piece of ceramic can be stored outdoors even if it doesn’t have a glaze, think about the terracotta plant pots in your garden, although they will not last forever as the ceramic is exposed to the weather.
- Water when it rains will get absorbed into the ceramic as it is porous. Frost has an effect too, frost is made from frozen water so this will also be absorbed, not only that but over time frost can damage ceramic as it affects the longevity of the ceramic structure.
So do you need to glaze your ceramic piece?
The answer to this can be determined by asking these questions-
Do you want your ceramic pieces weatherproof?
No, you do not need to glaze your piece but it does need bringing indoors in bad weather conditions.
Will my ceramics survive outdoors in bad weather conditions?
Possibly. If they are unglazed the lifespan may not be very long when exposed to bad weather conditions. If they are glazed they may survive outside for some time. Always remember both unglazed and glazed ceramics don’t last forever, bringing them indoors with help prolong their longevity.
Do you want your ceramic pieces to hold water?
Yes, you need to glaze your piece so that it holds water.
Do you watch your ceramics to function for food and drink use?
Yes you need to glaze your pieces. Glaze will make your ceramics water tight to hold liquid and the glaze also protects the food... but remember the glaze used needs to be FOOD SAFE!
For more information on ceramics more 'technical side'
keep popping back to read my monthly blog on the ceramics process.