Weathering well

Head of a terracotta pheasant covered in frostA FAQ by our customers is “Can I put my pottery outside?”

If they are doing our ‘Make & Take’ option and transporting their raw, clay pieces home, then it’s a big NO NO! At the first sign of rain their creations will reduce to a sludge.

We recommend a couple of layers of PVA glue mixed with water (50/50 mix) to seal the surface. They can then decorate their object with whatever paint they may have to hand. BUT, under no circumstance should the object be left outside in the rain as it will break down in a down pour. Air-dried clay is definitely for interior, decorative purposes only.

Fired things have made an irreversible chemical change and are much more permanent. Rain & sunshine will have little effect. Snow, frost and ice however, can be detrimental to fired ceramic. It’s all to do with the temperature the clay has been fired to.

The higher the temperature, the more likely the clay particles will have fused together forming an impenetrable material. It’s called vitrification. If on the other hand, if you have a relatively low fired pot, the clay particles will not have fused so much, resulting in the ceramic material being softer and porous to liquids.

As water freezes, it expands. So if you have a low fired pot, the water is going to soak into the body and when it freezes, the ice expands with enough force to fracture the material. Hence cracking and chipping occurs – frost damage.

If we know our customers work is heading for the garden, we will suggest an appropriate clay and purposely high fire the object.

Our Pottery garden is full of high fired terracotta – some of the pieces have been out in all weathers for 20 years or more and they still look pretty good with very little frost damage.

 

Comments are closed.