A granule is a tiny piece of metal that has been formed by heat into a spherical ball; the granules are then attached to a metal base to create complex designs. You’ve probably seen granulated pieces in art magazines and books. Granules have been found in jewelry and art pieces since ancient times. It’s hard to imagine, with limited resources, how the goldsmiths in that day and age were able to create such astounding works of art. Just think about the time and energy it took to make these intricate pieces using the sparse jewelry tools and supplies they had during this time period.
Over the centuries, the process of creating granulated pieces has changed. We now have kilns, electricity and commercially available solder, luxuries that ancient metalsmiths could not even imagine. If you have granules covering your piece then solder would not be the most practical option, yet using a kiln or fusion welding would be. That being said, I like to have granules on my pieces that are together in small groups so soldering is the best choice for me. Granules can be of any size, with as many or as few as you like and they can be formed from nearly any metal but the most popular are gold, .999 fine silver, sterling silver, and copper. Regardless of the type of metal, let’s first start with the “mold”, which can be used with any type of metal.
A charcoal block is a great mold to use when making granules. When heating metal, if the pieces of metal are too close or the flame blows the metal around, the pieces of metal can run into each other where they melt together and form a large granule. This means that you will need to measure and cut more metal pieces, and heat them again until you have enough granules for your piece. A charcoal block separates the metal pieces, retains heat making it quicker to form the granules, lasts a long time and is easy to modify for the task.
Note: At the bottom of this post there is a video showing each of these steps. I have placed the timestamp of where each step is located on the video so that you can quickly access the steps you’d like to see.
Step 1: Tools and Materials
- Safety glasses
- Paper towels
- Charcoal block
- The tool of your choice for holes (screwdriver, file, nail...etc.)
- Permanent marker
- Sterling silver wire, 22 gauge
- Wire cutters
- Air/acetylene torch
- Soldering Pick
- Pickle pot
- Quench bowl
- Copper tongs
- Sandpaper (optional)
Step 2: The Charcoal Block “Mold” [Video Timestamp - 0:55]
Charcoal blocks make a mess when you are drilling holes, so place paper towels underneath the block and wear safety gear (apron, glasses and a mask). This is the dirtiest part and your hands will be covered in charcoal dust, so I suggest using gloves if you can. Charcoal blocks also tend to crack under heat so I place binding wire around the block so if it ever does crack, it will remain in its original shape (you can keep the binding wire on the block forever, also).
To create your holes you can use a drill bit on a rotary tool or drill press, a Philips head or flathead screwdriver, a nail, pliers, almost any pointed object. My go-to tool when creating holes is the bottom end of a mini file. It is round and flat at the bottom, and it just sinks into the block with a few twists of my hand. You can create multiple sizes and depths across the charcoal block. Create your holes with a gap of about 3-4mm apart. When you are finished with the holes, tip it over and knock as much charcoal dust as you can onto the paper towel. Place your paper towel in the trash when you are done, it will be extremely dirty.
Step 3: Measuring the Metal [Video Timestamp - 2:50]
Unless you are making a jewelry piece that incorporates various sizes of granules, it is important to create sizes that are identical. There are several ways that you can do this:
- Twisting the wire around a mandrel, much like you would if you were making jump rings, then snipping or piercing them with a saw blade to separate the rings.
- You can weigh metal pieces on a scale (especially useful on larger granules and when using scrap metal)
- If cutting from sheet metal, you can measure and cut off even rows and columns
- You can use a ruler and measure, mark with a permanent marker (or scribe)and then use wire cutters to snip identical lengths of wire
I always use the ruler with copper or sterling silver wire. Many of my granules are tiny so 1/8th of an inch is my go-to size, usually with 18-22ga wire. I highly suggest making several granules using different sizes of metal to find out which sizes you like the most. Take very good notes on what length of wire or size of sheet matches each granule after you’ve melted it.
Step 4: Using the “Mold” [Video Timestamp - 5:41]
Using tweezers carefully place each piece of metal into your pre-made holes. Make sure it is one piece per hole. If it sticks out at the top that is fine, it will ball up when heated to its melting temperature.
Step 5: Heating the Metal [Video Timestamp - 6:58]
Using a large torch tip or flame (I’m using air/acetylene with #1 Smith torch tip), heat the wire pieces until they melt into granules and then remove the flame. Allow the charcoal block to cool for 5-10 minutes, it will be hot!
Step 6: Removing the Granules [Video Timestamp - 8:22]
Carefully grab the charcoal block on the opposite side from where the granules are and then simply tilt the block over to remove the granules. They will roll out along with some charcoal dust. If any remain in the holes, use your soldering pick to gently nudge them loose.
Note: Place the charcoal block off to the side in a safe location. It will remain warm for a couple of hours.
Step 7: Cleaning the Granules [Video Timestamp - 8:36]
Drop all of the granules into a pickle bath. Let them soak until they’re clean then use copper tongs to pull them out of the pot.
Note: Don’t ever use steel tongs or a steel dipping basket in your pickle pot, it reacts to the pickle solution and electrically charges the copper ions in the pickle pot, thus coating all your pieces with copper plating. When that happens it doubles up on your finishing work to remove it all.
Tip: Removing the loose granules from the pickle pot is terribly time-consuming. In the video below, I show a reused plastic top that one of us created here to hold the granules together. It’s nice to be able to lift them in and out of the pickle pot quickly!
Step 8: Sanding (optional)
Tip: If your granules are rolling around on your piece you can prevent this by using sandpaper to flatten one side of them slightly so that they stay in place.
Step 9: Soldering the Granules [Video Timestamp – 9:40]
Spray your piece with flux and then place a silver solder pallion chip (or several if you’re using multiple granules) on the sheet in the center of where your granules will go. Place your granules around the pallion chip and then heat your piece slowly by going in large circles around your piece moving in closer at each pass. By heating it slowly it prevents granules and solder chips from popping off while the flux dries. When the pallion chip flows, you can remove the heat. Drop it into a pickle pot to clean and then quench and dry.
Tip: Heat the largest piece first. Since my sheet is thicker, I concentrated on heating that primarily and then heated the granules during just the final few seconds.
Step 10: Video
Read this article How To Sweat Solder 14kt Gold To Sterling Silver to learn the sweat soldering technique used on this cocktail ring.
Erica Stice is the Studio Coordinator at Halstead in Prescott, AZ. She’s addicted to the flame of the torch and is always looking for excuses to solder. Forging is her second favorite technique.
1. Wikipedia: Granulation
2. AJU: Granulation and its Techniques