Firing Service

Onglaze firing to 800°C is only possible by booking a full kiln. Please telephone the shop 9387 3911 to enquire about prices for full kiln bookings.

Full Kilin Bookings for all types of firing are available. Please telephone the shop 9387 3911 to enquire about prices for full kiln bookings.

Turn around time for work being fired is one (1) week. Please telephone 9387 3911 to enquire if your work is ready if you are in doubt.

We take every care in the firing service to see that work is not damaged or stolen but the service is only as good as the people who use it. It is therefore a good idea NOT to leave the work uncollected for long periods and helpful if you keep a note of how many pieces you have brought in for firing. We do retain the right to refuse to fire WET, TOO THICK or DANGEROUS work in our kilns.

We look forward to assisting you with your firing in whatever way we can.

Northcote Pottery Supplies is open:

Monday- Friday 9.00am - 5.00pm
Saturday 9.00am - 4.00pm

TIPS FOR FIRING POTTERY SUCCESSFULLY

PLANNING YOUR PIECE
Mark the bottom of your work with your name and date and clay type.

The ideal thickness for handbuilt pottery is 1 – 1 ½ cm. Radical variations in the thickness of pottery promotes uneven heating and therefore cracking.

Very thick pottery is hard to dry fully and therefore will not fire successfully (i.e. it cracks, explodes) due to trapped moisture in the pottery heating and expanding.

DRYING YOUR WORK
The a) more joins, b) larger the piece or c) more uneven or variable the thickness of a piece, the more chance there is of cracking occurring in drying.

DRYING SHOULD BE SLOWED BY PUTTING PIECES INTO A PLASTIC BAG AND TAKING UP TO 2 WEEKS TO DRY SLOWLY & EVENLY.

Never rapid dry clay because it has a memory for the stresses which are created in making and these, coupled with uneven drying, can cause major disasters.

Never expose drying pottery to extreme cold or hot or variable conditions
(i.e. leave near windows in winter or draughty doorways in hot summer wind).

FIRING

Always know your clay type and glaze type - is it earthenware, mid-fire or stoneware/porcelain? The clay bag or glaze bottle will tell you.

Never put glaze on the bottom of pots; 1/2 cm up from the base is the best cut off line for glaze application - this ensures that there is no chance of excess glaze running and sticking your work to the kiln shelves.

Always read the instructions on glazes and underglazes and follow the manufacturer's recommendations. Do not over apply!

TRANSPORTING POTTERY

Newspaper is not always a good wrapping product for transporting pottery because it can often damage fragile work.

Pizza boxes are very useful for transporting slabs/plates.

Stockings filled with sawdust can be useful packing, as can straw, shredded newspaper etc.

Never pack layer upon layer of pottery into a box unless the largest and heaviest work is at the bottom and lightest at the top.

Remember, pottery items may move in transit! What will the consequences be for the pottery forms if they knock into each other?

Keep a note of what pieces you bring for firing so you can be sure to collect all pieces when firing is complete.

If in doubt, ring us for advice on (03) 9387 3911.

MENDING RAW CLAY WITH VINEGAR BASED SLIP RATHER THAN WATER BASED SLIP

This technique is only suitable for leather hard and almost dry pieces which are cracking, or have fallen apart. A vinegar based slip will help rejoining, but will not act like a glue to hold weighty pieces in position. Vinegar based slip gives much better results because vinegar is a flocculent which improves the possibility of a good mend and retards re-cracking. Once you have used the vinegar based slip to execute a mend, return the piece to a plastic bag and dry very slowly. Vinegar based slip is simply a mixture of the same clay that the piece is made from (in dry form), combined with any cheap vinegar to make a thick paste. Vinegar based slip could easily be used as your standard joining slip at all times. It's a good way to recycle any spare dry clay. Keep a pot on each work bench in the classroom.

PAPERCLAY SLIP FOR RAW AND BISQUE JOINS/MENDS Commercial paperclay bodies can be wet down to a thick paste to create a joining and mending slip. It is best if this slip is the same type as the clay to be joined (i.e. terracotta paperclay for joining terracotta clay). If you don't have the appropriate paperclay body, you can use dry fibre fluff ($15 for a large bag) which is the equivalent of the paper in paperclay, to create your own matching paperclay slip based on the clay you use. Simply stir some fibre fluff into your usual wet joining slip.

MENDING RAW/BISQUED CLAY WITH FIBRE CEMENT Remember: it's a 'big ask' to expect a mending product to stick a major weighty piece of clay onto another piece of ceramic work. Be reasonable in your expectations. Use the fibre cement as a glue to hold the two pieces together in position. Sometimes it's helpful to use masking tape to hold the pieces in place until they are fully dry. Once fired, the fibre cement changes from mint green to white, and you can easily glaze over it to disguise the join.

MENDING FIRED POTTERY ITEMS The Goddess Aralditus of Adhesion is really the best solution for these repairs, in particular, the five minute (2 part) Araldite. There really isn't any other glue that is as effective. Super Glue is impossible! Clear silicone bathroom sealer is acceptable for joins where much of the clay work is missing or chipped off and the glue needs to be a filler as well as a glue. But, silicone is very difficult to get where you want it and keep it neat at the same time. Tarzan Grip is a very ordinary glue other than for sticking little pieces onto small works.

OTHER JOINING/MENDING TECHNIQUES Some potters swear by using a paste of water-based clay slip with sodium silicate (a deflocculant material) for repairing raw clay. However, this technique often causes a crispy, flaky glossy area that is far too visible and not very nice to glaze over.

SOMETIMES REPAIRING IS NOT WORTH IT Don't be afraid to start again! Some repairs are so traumatic and take so long that the whole piece could have been remade in the time it takes to repair. Try thinking outside the square and consider whether the work can be mended using alternative methods - wire, cane, plastic tubing, nuts and bolts etc. can all be utilized in a more innovative and integrated way to become part of the finished work.