The thing that should determine whether you choose liquid or dry glazes is
how they are formulated, and how you plan to apply them. In most cases,
dry glazes are formulated for dipping or spraying, while liquid
glazes are formulated for brushing. The liquid glazes have
brushing medium (such as CMC
or brushing medium) so they can be brushed on.
You can add your own brushing medium to dry glazes, if you want to brush
them on. However, you can't take the brushing medium out of liquid glazes, if
you decide you want to dip your pieces instead. In some cases you can thin
liquid glazes to
help make them more conducive to dipping. However they will tend to dry more
slowly, so you may get drips or runs.
Specifics by manufacturer:
Spectrum glazes
-
Other than the Nova product line, liquid forms of glaze are designed for
brushing, and dry forms are designed for dipping. Nova glazes are an
exception because the whole line is designed for dipping; you can buy it
in liquid or dry form, but it is all formulated for dipping.
Coyote glazes
-
Are not formulated differently for dipping or
brushing. Coyote tries to use an amount of brushing medium that works
for brushing, but still works for dipping.
Amaco glazes -
Liquid forms of glaze are formulated for brushing, and dry forms
are formulated for dipping. Trying to add water to liquid forms of
glaze (to thin it) and dip is not recommended. However, Amaco does make a
product called suspendaid which you can use to convert a brushing glaze to
a dipping glaze. (We will be carrying this product soon.)
Laguna glazes - Liquid forms are formulated for brushing, and dry forms
are formulated for dipping.
Cost:
Some people believe there is a large cost savings in buying dry glazes,
however most of the cost of glazes is in the raw materials. As you
can see in this comparison for Coyote glazes, there is a slight cost advantage
to buying dry vs. liquid, but not that much. The real cost savings comes from
buying larger unit sizes (i.e. gallons instead of pints).
Coyote Shino example:
We did the same comparison on Amaco Potters Choice glaze. It was 37%
less to buy in gallons than pints. The 25# size was very close to the
price of 3 gallons, so the observation that liquid and dry cost about the
same holds true here as well.
Note: The amount of water to add to dry glazes varies. 25#
will make 3 to 3.5 gallons of glaze. It varies not only on the glaze
itself,
but on how you use it. The more porous your bisque, the more it will
absorb glaze. Also the number of dips and length of your dips will
affect how you should mix it. Many people use mixing guidelines such as
"the consistency of skim milk" or "the consistency of
cream." Whichever you choose, it is usually best for you to be consistent with your
bisque firing temperatures (which affects the bisque porosity, thus glaze
absorption), and how thickly you mix
your glazes. Then, adjust your number of dips and length of dips based
on firing tests you have done and the firing results you want to
achieve.
Also remember that dry glazes should be sieved after mixing.
In this process you push the mixed glaze through a sieve into a separate
bucket, then back again. We have more information on mixing
dry glazes.