Glazing Tips
Glazes usually must only be used on work which has had a first (bisque) firing.
All glazes must be thoroughly stirred before use so that there is not a thicker layer left at the bottom of the bucket. Some glazes may need stirring in between applications as they can settle rapidly.
Cover the glaze bucket between applications to avoid contamination by dust or other glazes.
Glaze can be applied by dipping, pouring, spraying or brushing or a combination of these. Be aware though that brushing does not usually produce such a satisfactory result because of the difficulty in applying an even coat and of avoiding brush marks.
Glazes are usually mixed to a consistency which need pots to dipped in the glaze for about 4 or 5 seconds to develop the required thickness of glaze.
The final glaze colour may be influenced by the colour of the clay you have used. When selecting a glaze from the samples make sure you are looking at the correct clay colour sample!
Never apply stoneware and earthenware glazes to the same piece of work. The two glazes need firing at different temperatures!
When both the inside and outside of a pot are being glazed it is inside which is generally glazed first.
Aim for an even coating of glaze about as thick as a thumb nail. Much thicker than this may lead to running or crawling. A thinner coat is unlikely to give satisfactory results. (This does not apply to clear glaze, see below).
When using a transparent clear glaze apply a thin coating. A coat of the usual thickness of a thumbnail will appear milky on firing and will probably craze. The best way of applying a clear glaze is by spraying.
Where possible use a glazing technique which will allow you to cover a surface in one go. If you glaze half of a surface and then turn the item over to glaze the other half it is almost impossible to avoid an overlap and therefore a different thickness of glaze. This usually will show up after firing as a band of different colour.
When using stoneware glazes it is most important that no trace of glaze is left on the bottom. A small rim must also be left clear of glaze at the bottom edge of the pot. If this is not done your pot will stick firmly to the kiln shelf and will need to be chiselled off. This will probably damage the kiln shelf and will certainly destroy your pot!
If necessary, glaze may be left on the bottom of a pot where earthenware glazes have been used, as at this temperature kiln stilts can be used under the pot to prevent it sticking. (these cannot be used at stoneware temperatures).