For the most part, I use commercial glazes purchased in a dry state which I hydrate and sieve. However, I also buy glazes in liquid form (usually in pints).
There are a lot of great commercial glazes and almost all of them are available as liquid in pints. Pints are cost efficient because they allow you to test a glaze prior to purchasing a larger amount. They are also excellent for supplementing a color palette (like at a community studio). I buy pints of glazes for colors that I don’t use frequently or for colors that are too expensive to use in large amounts. Pints are also space efficient since because you can store several glazes in a small space; and, they are portable which is critical if you do most of your glazing remotely (like in a community studio).
If you buy a pint, it is most likely that you will brush the glaze onto the pot. Although the glazes are liquid, they may need some attention prior to using. The ‘right’ glaze consistency is smooth and flow-able and results in the coverage that you want. Unfortunately, for those of us who like to quantify things, this is a judgement call. Don’t be afraid to adjust the glazes to suit your application style.
Some glazes settle quickly or may have settled since they were shipped. Other glazes may be too think for brushing or ‘lumpy’. Glazes in these conditions need additional water and/or sieving.
The first thing to do is shake and stir the glaze. If this doesn’t result is improved viscosity, add a little water and stir and shake the glaze pint again. The glaze is at the appropriate viscosity when it is flow-able enough for you to work with in a way that is comfortable to you and coats the pot adequately.
If the glaze still doesn’t look smooth, then sieving can help improve performance. Sieves come in various sizes – typically 60, 80, 100, and 120 mesh. The larger the number, the smaller the holes (sort of like thread count for bed sheets). If you have a very lumpy glaze, you may need to sieve progressively. Sieve with the lowest mesh first (60) then sieve the glaze again with a higher mesh (80). I sieve most pints one time with an 80 mesh and that seems to be sufficient. Pottery Supply House sells sieves that are fitted for wide-mouth pints at a very reasonable price.
Stir and shake the pint, then pour the glaze through a sieve. You will need to stir the glaze to move it through the sieve. If the glaze is too thick, add a little water. If you add too much water and the glaze becomes too thin, let the glaze settle for a few hours or days, then decant some of the water off the glaze. Stir and shake the pint and sieve again if necessary.
If the glaze dries out, it can be rehydrated. In fact, if a glaze is partially dried out, it is best to allow it to dry out completely. Just leave off the cap until all the water evaporates. Then, add water to the dry glaze, allow to hydrate then sieve it.
Pints of glazes are an economical solution to expanding your color palette and with a little adjustment, you can make using them more enjoyable.