Enameling is the art of fusing glass to metal. The basic procedure for enameling is to apply the enamel to clean metal, and heat the piece either in a kiln or with a torch to a temperature of 1500 degrees or so, until the glass enamel melts and fuses to the metal. Enamels come in powdered and liquid forms, but powder is more commonly used because it is easier to apply and comes in a wider range of colors. Enamel can be fused to gold, fine silver, copper, and steel. You can enamel on sterling silver too if you depletion gild or "bring up the fine silver" first, but that would be a whole different tutorial. I would recommend starting with copper, because it is very inexpensive compared to gold and silver, and it is very easy to work with.
Safety: The main safety issue when working with enamels is the heat. Make sure you are firing away from flammable materials, on a heat proof surface. Don’t leave your kiln unattended when it is hot. If you are using a larger kiln, you will want heat proof gloves to protect your hands. Wear tinted safety glasses to protect your eyes from the light of the torch or kiln. If you are sensitive to dust, you may want to wear a dust mask when sifting enamel.
-Copper sheet, 18 or 20 gauge and jeweler's saw or disc cutter to cut out shapes
-Precut copper shapes from an enamel or jewelry supply company
-80 mesh enamels- you can get enamels from various places, but I like Thompson Enamel
-Holding agent- this is an organic gum solution that acts as a sort of glue to hold the enamel powder on the metal
-Sifter- you can buy these in various sizes from enamel supply companies or make your own by cutting the bottom out of a plastic cup and gluing in a piece of fine screen
-Ball Clay or Scalex (optional) - This is a clay slip like substance used to coat the un-enameled side of a piece during firing.
-Pickle Pot and Copper Tongs- to clean metal
-Pumice powder, scouring powder, or commercial metal cleaner to clean metal.
-Kiln- there are two basic types of kilns. The cheaper kind (which I have) is called a beehive or hotplate kiln. It's basically a heating element set inside a round chamber with a domed lid. This kiln is great for doing small pieces, but it does have its limitations. The other kind of kiln is like a little oven with a door that opens in the front. These can accommodate larger pieces, and you can get them with fancy features like temperature controls and shutoff cycles.
-Metal Spatula or fork- for moving pieces in and out of the kiln
-Firing Supports- Trivets and/or wire screens. The firing support should hold the enamel while firing and allow you to transport the enamel piece in and out of the kiln with your spatula. The trivet is made with three or more angled metal arms that hold the enamel by its edges. Some trivets have built in legs so you can slide your spatula under them to move them. Some trivets don't have legs and need to be placed on a wire mesh firing screen with the corners bent down. You can also improvise a piece of steel with bent down corners to set your trivets on (see the firing photos below)
-Torch- Any kind of torch used for jewelry making will work. I use a super basic propane torch from the hardware store. It's inexpensive and convenient, but doesn't get hot enough to fire pieces larger than 1" in diameter. Acetylene and propane/oxygen torches get hotter, and can fire larger pieces.
-Firing supports- Trivets. For torch firing you need something you can get your torch under to fire the enamel from below. A tall enough trivet will work or you can get a tripod with a mesh screen on top and set your trivet on that.
Preparing the metal:
-Cut the shape you want out of copper sheet, or use a precut shape.
-If you want to dome or otherwise form the metal, do it now.
-Clean the metal- I find the best way to do this is to heat the metal to a dull red with a torch to burn off all the dirt and oil, and then pickle it. Otherwise, you can scrub your metal with pumice powder or household scouring powder, or use a commercial copper cleaner. Once your metal is clean don’t touch it! The oils from your fingers will prevent the enamel from adhering properly. Use tweezers to pick up the metal.
Sifting the first coat:
-You will want to enamel both sides of your metal. The enamel on the back of the piece is called the counter enamel. If both sides of the piece will be visible when finished, choose an appropriate color. If the back will not be seen, you can use mixed odds and ends of enamel.
-When firing the first coat of enamel, the other side will be blackened by the heat of firing. There are two ways to deal with this. You can use ball clay or scalex to coat one side of the metal before applying enamel to the other side. This is a sort of clay like product that protects the metal during firing. You just paint it on and after firing it flakes off the metal. Otherwise, you can just enamel one side and then pickle the piece to remove the oxidation from the bare metal. I prefer this method, because it seems to work better and it’s less messy.
-Holding your metal in a pair of tweezers, either spray or paint on a thin layer of holding agent. You want just enough to hold the enamel powder onto the metal, not a big puddle.
-When sifting the enamel, you can set the metal piece on a piece of glossy magazine paper to catch the extra enamel. If you are making a larger piece, it helps to put a something under the metal to lift if up off the paper and make it easier to pick up. A soda bottle cap works nicely. Otherwise, you can hold the piece in a pair of cross-lock tweezers directly over the jar of enamel while you sift. I like to do this when making small pieces.
-Put some enamel in your sifter, and gently tap the sifter with your finger to springle enamel onto the metal. You want to apply a thick enough layer of enamel to cover all the metal, but not too thick. It might take a few tries to get it just right, so do some experimenting.
-Once the enamel is applied, let the holding agent dry completely before firing. If you try to fire a piece before it is completely dry, the liquid will boil away causing enamel to pop off of the piece. If you are kiln firing, you can set the piece on its firing support on top of the kiln lid to dry. If you are torch firing, you can set the piece on its firing support and very carefully heat it from below to dry it.
-Use your spatula to transfer the piece on its firing support into the kiln. Firing times vary depending on the enamel color, the thickness of application, and the size of the piece, so you can’t really time the firing. Take a peek every so often to see how the piece is progressing. First the enamel will start to melt into an orange peel texture, then it will fuse fully and smooth out.
-Once the enamel is fully fused, use the spatula to remove the piece from the kiln. Let it cool on its firing support
-With the enamel piece on its firing support, heat the piece from below with your torch. The enamel will blacken where the torch hits it. You will be able to see the progression of the enamel melting and fusing to the metal. Even if you are using a kiln, I would recommend torch firing a piece to get a better understanding of what happens during the firing process.
-File the edges of the metal to remove any oxidation or stray enamel. You will need to do this after each coat you fire.
-Clean the un-enameled side of the metal thoroughly.
-Sift a coat of enamel onto the un-enameled side.
-Dry and fire as before.
-Continue to apply coats of enamel until you are satisfied with the appearance of your piece. Chances are your first coat won’t look so great. It may be uneven or bumpy. As you apply more enamel, you will get more even colors and a smoother surface. Three coats of enamel will usually give pretty good results. Try layering different colors of enamel. Experimentation is key when learning how to enamel, so get yourself a bunch of little pieces of copper and go to town.