Fluxes for Enameling, Firing Temperatures, and Color Charts

Fluxes for transparent and medium firing enameling. Firing time varies on the size of your jewel. I work small and like to start around a min and go up in seconds. Just a quick peak in the kiln at eye level you can see if the enamel has fused.

 

What is flux? it could be thought of as primer when you are painting a wall, or gesso on and oil canvas. It is a base coat of enamel that allows enamels of a wide range of physical properties to be use in this technique and not burn.

Copper

Fire at 1450 and up to 1550 degrees

Thompson’s Unleaded 2030 Flux. Here is a link to Thompson’s Color Chart of Opaques for Copper

Thompson’s Color Chart of Transparents for Copper

Ninomiya’s   Leaded L11  Flux   Here is a link to  Enamel Works Color Chart of Opaques for Copper

Enamel Works Color Chart of Transparents for Copper

Enamel Works Color Chart of Opalescents for Copper

Bovano’s   Leaded #1 Flux   You can down load their color chart here,

Bovano’s Color Chart of Opals, Opaques, and Transparents for Copper

Fine Silver

I make enamel and cloisonne jewelry. And Fine Silver is my choice of metals. The weight of the jewel as well as the strength is a factor and in choosing the gauge of the fine silver. For pendants I prefer 20 gauge and for earrings 22 gauge.

Fire at 1425 – 1450 degrees

Thompson’s Non Leaded 2020 medium firing or 2040 for a hard firing fluxes. In my work I like a hard firing flux on my bases.   Here is a link to Thompson’s Color Chart of Opaques For Fine Silver

Thompson’s Color Chart of Transparents for Fine Silver

Ninomiya’s Leaded  N1 Flux                         Enamel Works Color Chart of Opaques for Fine Silver

Enamel Works Color Chart of Transparents for Fine Silver

Enamel Works Color Chart of Opalescents for Fine Silver

N3 = Leaded pre – washed flux

G 110    Leaded hard flux

Bovano’s     Leaded  #3 this is a hard flux with a blue base, this is my favorite flux on fine silver.

Bovano’s Color Chart of Opals, Opaques, and Transparents for Fine Silver

Sterling Silver

Thompson’s Non Leaded 2040 flux.    Thompson’s Color Chart of Opaques For Silver

Thompson’s Color Chart of Transparents for Silver

Ninomiya Leaded N1 or N3 Flux      Enamel Works Color Chart of Opaques for Silver

Enamel Works Color Chart of Transparents for Silver

Enamel Works Color Chart of Opalescents for Silver

Bovano’s #3   Leaded Flux, both of these are hard enamels and I think it is helpful in keeping the surface contamination down of the sterling silver away from the layers of enamels.

Bovano’s Color Chart of Opals, Opaques, and Transparents Silver

Gold

Fire at 1425 – 1450 degrees

Bovano Leaded #2 Flux and a link to, Bovano’s Color Chart of Opals, Opaques, and Transparents for Gold

Stainless Steel

Fire at 1250 Degrees – 4-8 min.

Low to Medium expansion Enamels     Thompson’s Color Chart of Opaques for Stainless Steel

Thompson’s Color Chart of Transparents for Stainless Steel

Finishing Fluxes

Ninomiya’s Leaded N4

Bovano’s  Leaded 619

Brass  Today is Gilded Metal

Today many are asking about enameling on brass. It needs to be gilded meatl, which means it has 5% zinc and no more to be successful, with 95% bronze. You can obtain this from Thompson’s Enamel and use their unleaded enamels used for copper as long as you have no more than three firings.

What are Enamels

History and Facts About Enamels

Art Enameling on Metals by H.H. Cunynghame  1906

Metals such as gold, silver, iron, copper and fine brass; copper with a small amount of tin, are capable of being enameled. But nickel, zinc, or common brass, which contains a mixture of copper and zinc are not capable of being enameled.  Mr. Cunynghame, first speaks of the art of enameling is simply melting glass on to the surfaces of various substances capable of adhering to it and also capable of withstanding the heat necessary to melt the glass and cause it to flow. Mr. Cunynghame, speaks of the common technology of producing Crockery, with is clays consisting of silicate of aluminia and magnesia, and forming it into shapes and firing it. After this process it is know as biscuit ware, and is hard and porous. At this point glass ground to an impalpable powder is mixed with water and the vessel dipped into the glass slurry, dried and fired to the melting point of the glass. In this respect the glass is called “glaze.” Very similar to our enameling and as well as the commercial applications of enamels or glass on other foundations such as iron= stoves and refrigerators or bathtubs. And don’t forget the use of enamels on signage.

Glass consist of sand and an alkali such as soda or potash, fused together with the addition of ingredients to produce color. He states the peculiar value here of lead. It gives the glass the remarkable ability to adhere to and run over the item being enameled and prevents it from cracking. He state it makes the glass more elastic and enhances its’ ability to withstand extreme temperature changes.  He also says that glass without lead is not suitable for enameling, as it will crack away from the metal. Of course today we have found a way to produce enamels without lead. The replacement for the major part is borax.

Glass is colored by melting it with the oxides of various metals. Oxide of tin makes it opaque white, iron gives it a sea green and yellow, cobalt a royal blue, and copper a turquoise blue. Manganese colors glass violet, silver and antimony yellow, and gold crimson. Also we have chromium, producing a fine shade of green; uranium, a fine yellow; and iridium, giving enamels the shades of steel gray and black.

Coefficient of thermal expansion is when the temperature of a substance changes. The energy that is stored in the intermolecular bonds between atoms changes. When the stored energy increases, so does the length of the molecular bonds. As a result, solids typically expand in response to heating and contract on cooling. This dimensional response to temperature change is express by its coefficient of thermal expansion. This is where many get lost.

In enameling you just need to match the expansion of your metal and your enamels. I use a harder firing enamel as a flux = base layer in the technique of cloisonne, , still in the family of medium expansion enamels but slightly harder.  Then continue with medium firing enamels just a bit softer. For the very simple reason, with repeated firings the base flux layer is harder to flow, and the medium temp enamels flow or fuse faster. If the base layer melted at the same temperature and time as the later layers it would be possible for your warm colors to get liquid enough to mingle down through the base flux and eventually touch the metal and burn. We are using medium firing enamels, they are for copper, sliver and gold metals, but a few are a little bit harder than others and these should be laid down first.

If you make test plates you will see this. Below I have a plate 1″ x 3″ and I put 15 color dots of washed enamel on the plate and fire it at 1425 degrees. Some dots are completely fused and some are still grainy. The grainy one is a harder firing enamel and takes more time to fuse.


Another point here to help in the technique of plique a jour, as well as in cloisonne, you do not want to put a harder firing enamel next to a softer firing enamel, again you will have cracking.  When cooling the less expansion enamel right next to the high expansion enamel do not mingle,  and separate= cracks.In this piece I made for Andre of Outkast, he wanted the cloison wires to be fine silver and different thicknesses. Which caused a lot of heat and of course with a pink nose against the fine silver cloison wires was trouble. But in my pallet of colors my pinks were not of the same firing hardness, once the cracking started, I had to remove them and test to get ones that were all the same to get the cracking to stop. And I am not talking about layering these colors I was gradating the colors next to each other. Things like this teach you but it would have been nicer to know ahead of the project.

When you get into plique a jour you will find it is also important to know your enamels melting points as in grouping or shading. When laying colors next to each other with no backing it is more obvious if the colors do not blend together. When the grains do not mingle and with out the back foundation as some expansion unity it is more likely to have cracking.

Happy enameling!

Color Plates and Understanding Expansion of Your Enamels

Color Plates

Color plates are very important. And yet so many choose not to do them. I know it takes time and you can get recommendations of colors from other artist, but if you have a direction in your work, by that I mean, a vision of your complete art form, and you want to get to that vision the practice of doing color plates can not only save you time and frustration but also end with the beautiful jewel you had visioned. As in rendering a water color of your visioned jewel can help you with your color choice, making a color plate to test how the colors work together can make you more successful in this medium.

This  is a color plate,

There is a lot of information on this plate, see what you can find. No matter if you are working in the technique of Cloisonne, Plique a Jour, Champleve, or sifting on colors of enamel, you should know the properties of the products you are working with.

1. This is my pink color plate. Some artist have just a few colors and mix two, to get a color shade in between them. I prefer to have separate colors, one reason I have mixed colors together and came out with a speckled effect, so I have a choice to set them next to each other to work in a color family and be able to go from light to dark.

Also there are problems here. And if you were to mix some of these together you will have cracking.

2. First, I notice the 4th enamel dot did not flow at the same temperature and time as the rest of the enamel dots. This means the expansion rate is different in the two enamels. The one that is grainy has a higher expansion rate, than the ones that are smooth.

You can layer enamels of different expansion rates with the higher on the bottom but if you put them side by side in a cell or on any enamel piece you will have cracking. The odd thing is it may not crack today or even next month, it could be in two years. Enamelist like to use the terms soft and hard enamels. Hard enamels on the bottom and soft enamels on top. Enamels that are hard are used on the bottom as it takes longer for this enamel to fuse and flow smooth. This also gives you a hard base that will not become liquid at the same time as the second and third layers of enamels you use to create colors. What does this mean? If you like warm colors and we all know warm colors burn. This can help you prevent that. The reason they burn is they come in contact with the metal. So ideally you want to keep them away from the base metal. And with a hard base = flux or several layers of a hard flux your warm colors will not penetrated to the lower levels and touch the base metal. This way the in the next layers softer enamels will fuse and flow before the harder base enamel becomes liquid= no burning. I recommend Bovano #3 for fine silver as it is harder than other fluxes I have tested.

3. The 7th color dot has a bit of yellow in the base color. What would this mean to the enamelist? Enamels have colors bases of yellow, ash or blue. When you line up your colors this way you can easily see which are which. If a color you have chosen for your design has a yellow base, you would want to add it as you last color layer as it will also have a tendency to burn.  Your enamels with a blue base or an ash base are safer. And yes you have yellows that have an ash base, or ones that are true yellow. = Test plates!

4. # 10 and #13 Are pinks with a blue base. These are less likely to burn that the yellow base ones, but will if allowed to come in contact with the metal. If you want a yellow pink just use the blue base ones first then the yellow.

These two images show problem with the soft enamel being used on the bottom and the harder enamel on top. When heated the soft enamel bubbles up and around the hard enamel.

Carving in the Enamel

Some thing you can do to enhance your work is to carve in the enamel. On this Nautilus Pendant I used white Askansas Stones to carve out the shape of the shell’s spiral.

Hi Jennifer,

Thank for the visit. I was not at the conference, but Merry-Lee Rae presented a lecture on cloisonne and used my images.

On carved enamels, yes I used a layer of flux and two layers of transparent red enamel. You can use a very fine diamond bit and arkansas stone bits. Afterward you should glass brush and or steam the piece to remove any trace of the stone and flash fire.

But as you know the layers are thin as transparent enamels need to be for clarity. And if you lay in the enamel in that small of a space it flows even. The chased flower petals had ridges and valleys. To enhance the visibility of this I carved in the top layer to follow this and expose the ridges more.

The Nautilus is also carved. This is posted in the topic Enamels, under Carving in Enamels. But this is a complete cloisonne piece, so the wires are at least .040″ high. And I actually over filled this, then carved the spiral of the shell into it.                            

Good luck, Patsy Croft

Cracking in the Enamel

Hi Patsy,

First of all, thanks for doing this blog; it’s obviously a big help to many people.

I’m relatively new to enamelling; I’ve done mostly flat pieces that have gone basically well. I just enameled a pair of earrings that developed serious cracks. To fabricate them, I cut two pieces of fine silver, textured them, domed them, and soldered on ear posts using IT solder. There’s no counter enamel… but I have a funny feeling that the square-ish shape, as well as how many layers of enamel (3), might have something to do with the cracking.

The cracks are forming in a circular form in the middle of the piece.

Thanks in advance,
DB

Hi DB,

You have to have the same number of counter layers as you have on the top. So now you can add the counter, and the cracks will go away! Quick edit, it also looks like you have higher enamel in the center than on the edges. This will add to the circular cracks.

Happy Enameling, Patsy

White Specks in Your Enamel

If you see white specks in your enamel, remove them. This is a sign of deterioration. Some times there is only a few and you can remove them before you place any enamel in your work. Sometime the enamel sits on the bottom and water will not penetrate the enamel at all. This it time to throw them away!

If you did not see this until the enamel is fired you can drill it out with a diamond bur and re-fire the piece before adding more enamel. This way you will not have a shadow where you removed the speck.

This is a real issue when using transparent enamels, an it comes from the enamels being left wet too long.