Cadmium Yellow pigments are the most durable yellow, orange and red inorganic pigments commercially available. They have excellent chemical and heat stability and can be used in chemically aggressive environments and durable applications without color fade.
Cadmium zinc sulfide pigments were developed in response to the need for stable, lighter shades of cadmium yellow. Cadmium and zinc salts of the same anion are used to form the pigment with up to about 25% zinc content.
Origin and History
When first introduced, there were few stable, bright pigments in the yellow to red range, with stable orange and bright red being very rare. The cadmium yellow pigments eventually replaced compounds such as mercury sulfide (vermilion) with improved lightfastness.
Cadmum sulfide was suggested as a pigment in 1819 by Stromeyer, but it was not commercially available until 1840s due to scarcity of metal required for its production.
About half the consumption of cadmium, which is about 2,000 tons annually, is used to produce colored cadmium yellow pigments. The principal pigments are a family of yellow/orange/red cadmium sulfides and sulfoselenides as well as compounds with metals other than cadmium.
This article comes from naturalpigments edit released
ENAMEL SUPPLEMENTS – For Medium Temperature Enamels for Copper, Gold, Silver, Low Carbon Steel, Window Glass, Stained Glass, Bulls-eye and Spectrum Glass, Effetre (Moretti), 400 Series Stainless Steel and Pottery (A.K.A. Ceramics)
Enamel Powder for Metal
A series of vitreous enamel powder for metal which fuse slightly below 1200ºF. Mix with your favorite painting medium.
The enamel powder for metal will attach to glass at 1250 degrees F. They will gloss between 1300 and 1400 degrees. F. They may be taken up to 1450 degrees F. without loss of color. Firing times and temperatures are only guides. Your actual experience may indicate the firing may need to be more or less time and temperature.
You may want to vent your kiln as it heats up to allow for any painting medium fumes to escape kiln.
This article comes from Thompson Enamel edit released
Porcelain is made from baked clay
Porcelain itself is a ceramic material made from a type of white clay called kaolin, plus feldspars, quartz, steatite, and other rocks. To make regular porcelain, the whole mixture is baked at 1300-1400 degrees. Porcelain enamel is made when the porcelain is melted together with a stronger metal. This makes porcelain enamel cookware both light and strong, with low porosity, so it is naturally non-stick.
Pay attention to porcelain coatings
Oddly enough, though, some companies seem to want to coat their porcelain enamel cookware with chemical non-stick coatings or to use potentially toxic heavy metals and other compounds in glazes and in the enamel mixture. It pays to be picky about porcelain enamel cookware and to ask questions of manufacturers if it’s not clear what they use in their pots and pans.
Unlike somewhat terrifying porcelain dolls that could be extras in a Stephen King movie adaptation, porcelain enamel cookware is a fun addition to the kitchen. That’s because it is available in a variety of colors and does not fade or peel when used according to instructions. My advice, though, would be to avoid porcelain enamel in reddish tones and to favor those that are blue, given that some Le Creuset models with a red tone have tested positive for lead and cadmium. The Signature Enameled Cast Iron Braiser (in a blue shade like Marseille or Marine) from Le Creuset is a good option for one-pot meals (View on Amazon).
This article comes from leafscore edit released
Those skilled in the enameling art have tried for years to produce multi-colored articles wherein the colors are overlapping or adjacent to each other by vitreous enamel coating and in a single firing operation, however, the best that has been accomplished before my invention is the production of articles which may have more than one color thereon, provided that such colors do not touch each other, or provided they are not overlapping or superimposed one on the other. .As heretofore practiced, the manufacture of multi-colored vitreous enameled articles has been carried out by a separate firing for each color when it is necessary to overlap or superimpose one color upon another. In the manner in which the colors have been applied in the past, if separate firings are not accomplished, then the finished article will be full of blisters and enamel defects and if separate firings are accomplished the finish will not be uniform, but will be stepped up, each subsequent color coating being higher than the last. Also every time a color coat is fired the color fades out so that the first color applied has changed to an undesirable shade after repeated firings and the colors lose the desired brilliance. Furthermore, there is a limit to the number of firings to which the first coat applied can be subjected, so that the prior process has serious limitations.
In the enameling art, as heretofore practiced, coatings averaged about 1% ounces per square foot of surface, (dry weight); some coatings may run as low as 1 ounce or may go as high as 1% ounces per square foot. The vitreous enamel coating in the present practice should pass through a 40 to 60 mesh screen and in some cases, such as for silk screen work, they are put through a screen as fine as 200 mesh.
A further object of my invention is to produce a multi-colored vitreous enameled article, or one having different hues, shades and different color tone in one firing and having a substantially smooth surface thereon free from blisters and blowholes and other enamel defects.
Another object of my invention is to reproduce vitreous enameled products of various colors, which may be superimposed, one upon the other, by a printing press. My invention generally comprises a wet enameling process wherein I start with a. metal base upon which one ground coat and one or two cover coats of enamel have been applied, this ground coat being a vitreous enamel coating 16 fused to the metal base. I then may apply a fine “wash coating” of frit over the surface to which other colors are to be applied; this wash coating may contain some coloring matter or it may be white. In the wash coating just referred to and in subsequent frits and colors applied to the article thereafter, the particles in the frit and coloring matter may be, and preferably are, of a size to belong to the class of dispersoids; that is, the solution is such that the particles range in size from 0.1 micron to one milli-micron, a micron being equal to .00003937 inch.
This article comes from FPO edit released