Pottery and Ceramics
Glazes are the protective coatings that make ceramics safe, useful and beautiful. Without the fired surfaces, pottery and ceramics would not be able to hold water or be safe for food.
SurfaceThe first category for glazes deals with how the surface will look.
The following terms will help you understand the labels more clearly and will allow you to make the best choice of products for great looking results.
Some glazes fall in between all of these groups.
Some glazes even have tiny specks or granules of a contrasting or complimenting color floating in them.
GlossShiny and smooth, bright high gloss and a highly reflective surface.
SatinNot really shiny, but not dull either.
Think of an eggshell or a satiny sheen.
The opposite of gloss.
This surface is duller than satin, reflecting little shine.
Even duller than matte.
This surface reflects no light.
Refers to the transparency of the glaze.
Some glazes are so transparent that it's like placing a clear piece of glass on top of your pottery or ceramic.
These clear glazes can act like a magnifying glass on top of the pottery or ceramic surface or on top of underglazes.
Some glaze colors are nearly opaque and others totally so.
THE CODES AND DEFINITIONS FOR THE OPACITY OF GLAZES ARE:
C: ClearThe glaze is completely clear, adding only a shiny, wet look and bringing out the true underlying colors on the piece.
T: TransparentThe color underneath is slightly tinted by the overlying glaze changing the appearance only a little.
ST: Semi-TransparentThe underglazes beneath these are identifiable, but are changed by the tone of the glaze over them.
SO: Semi-OpaqueLight underglaze colors will not show through and dark colors will be muted.
O: OpaqueMost colors will not show through.
SAFETYOne of the most important considerations when choosing a glaze deals with whether they will be used on utilitarian or serving pieces.
Several words are used to describe the level of potential hazard that a glaze poses to a customer.
Some words are used to describe the product in the liquid state and others are used to describe the finished glaze surface after firing.
To determine the toxicity of a glaze in its liquid state, formulas are submitted to an independently licensed toxicologist who examines each glaze formula and determines whether the product can be labeled as non-toxic or whether it requires a health caution label.
To determine a glaze dinnerware safe, a second set of tests are required.
Samples of the glaze in its fired form are tested by an independent laboratory facility for leach ability of lead and cadmium.
If the surface passes the standards set by the Food and Drug Administration (FDA), then it may be used on food contact areas and can be labeled as dinnerware safe. Dinnerware safe only refers to the leach ability of lead and cadmium; other surface characteristics are not considered.
Be aware that if a finished surface is bumpy, grooved, pitted, cracked or rough, there is potential for bacteria to hide out in the surface texture.
Even if a glaze is technically dinnerware safe, it may not be practical for use on food or beverage containers due to the difficulty of cleaning.
A comparison would be a cutting board and the care required when preparing foods.
Non-ToxicRefers to the product in the jar.
Contains no harmful ingredients in sufficient quantities that could be harmful to humans.
Health CautionRefers to the product in the jar
There are some ingredients present in large enough quantities that the product may be harmful to humans.
There will be detailed information on the product label as to the type of risk that is posed as well as proper handling instructions.
Even more detailed information is available on the relevant
Material Safety Data Sheet (MSDS).
Dinnerware Safe and Food SafeRefers to the finished, fired surface of the glaze.
Once fired according to the instructions on the product label, the fired surface may be used in contact with food or beverage without leaching potential harmful elements from the glaze into the food or beverage.
Not for Dinnerware Use and Not for Food UseRefers to the finished, fired surface of the glaze.
Even when the glaze is fired according to label directions, the fired glaze may potentially transfer harmful elements into food or beverage upon contact.
Here are some examples to illustrate the differences:
Stroke & Coat GlazesThey are non toxic and dinnerware safe.
There are no toxic elements present in the liquid state and therefore, no toxic elements will be leached into food or beverage.
Classic Crackles and CrystalitesThey are non-toxic, just like the Stroke & Coats.
And although they are also dinnerware safe, the surface should be examined to determine if it is easily cleaned after food contact, having no bumps, cracks or grooves.
C-109 Wonder Clear Dipping GlazeIt has a health caution and is dinnerware safe.
There is lead present in the liquid glaze and care must be taken to avoid exposure through inhalation or ingestion.
But when fired according to label directions, the fired surface of C-109 conforms to the standards established by the FDA and is dinnerware safe.
Other products, like Exotic Glazes, have a health caution and are
NOTfor dinnerware use.
There are potentially harmful elements present in the liquid glazes and instructions must be followed for proper use to avoid exposure.
Even when the glazes are fired according to label instructions, they should not be used on food or beverage contact areas, as enough of the harmful elements may be transferred to the food or beverage to be considered harmful to humans.
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Have you ever come up with a good idea while working with your handmade pottery or ceramics and thought that you would like to share it with others? You have? Well, why not send it to us and we will add it to the tips page for all to see.
Handmade pottery can be a very gratifying hobby that produces fun and satisfying results. For many people it's an enjoyable release that is created by working an inanimate mound of clay into a beautiful work of art that you made through your artistic abilities.
The best way of starting out is to take a few lessons. You will probably waste quite a bit in materials when you first get started. Figuring out how to truly make handmade pottery correctly and shape into what you want it to be can be quite an ordeal. The different tools that a normal shop will have can be fun to try. You will soon see which ones you like to use the most and then when you are ready you will know which ones to buy.
With the help of the internet, you can now purchase most if not all of your ceramic and pottery tools and supplies online. We are located far from any well supplied dealers and yet working with reliable ceramic and pottery suppliers online has allowed us to recieve most of our orders within a timely manner.
When you get all set up, just enjoy the hobby and have fun at it. Some people get pretty serious and start selling their creations at craft fairs and small stores, but others just like to create items for themselves, relatives, and friends. Whichever kind of handmade pottery you desire to endeavor, enjoy the hobby and have fun doing it.
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