PrintFREEFORM FLUTED BRACELET
7/3/2015
By Bill Fretz
We’re going to take the same metal blank used for making a concave bracelet and instead use it to make a domed fluted bangle. Choosing different stakes and hammers will create a piece that doesn’t remotely resemble its genetic cousin. Along the way we will explore variations of how a step may be done, and the pros and cons of each solution. The more a craftsperson knows about process, the easier it is to create new work that ventures into new arenas of design exploration.
The design silhouette needs to be transferred to a piece of sheet brass 8 ½ inches by 2 inches by18 gauge.
The design on paper could be traced with a marker or glued down with rubber cement. If you use rubber cement make sure you have a back up pattern as the original will become useless after it is removed. A wide pine board clamped to the workbench with a c-clamp makes a perfect bench pin or V-block. The obvious way of cutting the bracelet blank out is with a deep saw frame with 2/0 blades or thinner. Doing it this way usually requires reversing the blank and sawing from both ends.
The quicker way is to use a Beverly Shear. The shear is just a large compound cutting device with a slightly domed cutting surface. The long handle on the shear also gives added leverage for making the cutting effortless on thin brass. This is a tool used by sculptors, sheet metal fabricators and custom cycle shops. We are using metal and the tools from any metal process can come in handy in fabricating jewelry. Studying other metal trades is another way of expanding the techniques available to the jeweler.
It is important is to adjust the blades so they are very close but don’t bind as the shear handle is pulled down. The trade off for speed is that the shear may make the shape slightly bowed. Since we’re going to form it round this is not a problem. The cutting time drops from twenty minutes to about two. The decisions concerning tool purchases are always the same. Do these tools help with designs that will be made repeatedly, and is the cost vs time justified? Quicker still would be having a die made for a really large production run. But then we are moving away from hand work and the
“pleasure of the process” to a business model. We’re focusing here on the art of metal working so we will leave industrial techniques to others.
Annealing is the process of softening metal by heating it. With the brass alloy of 70% copper and 30% zinc, the correct temperature can be achieved by heating the metal to a dull red in a darkened room. If the annealing pan is well lit and the color is hard to see you can use handy flux as a heat indicator. The flux will turn glossy at about 1200 F, indicating the temperature is about right. A bed of pumice is a good reflecting surface. Make a flat bed by placing a firebrick on the pumice and move it back and forth.
When removed the flat surface will ensure even heating. You can purchase a sheet metal annealing pan or you can make one from two cast iron frying pans and lazy-susan hardware. The advantage of the cast iron is that it won’t warp from repeated use. Having the annealing pan rotating smoothly is a big help for large soldering projects.
The blank can soldered with a butt seam. That is the simple procedure of bringing two flat ends together to be soldered with hard silver solder.
This seam will hold unless it is stressed with severe hammering. Another method is to do a lap seam. A lap seam is formed by filing the opposite ends of the blank to flat bevels, and then having the two sides overlap. It is important to remember after filing one end that the piece has to be flipped over so the bevels are on opposite sides. First mark the opposite ends of the bracelet with a caliper opened 2 mm. An easy way to form the line is to slide the calipers along while the lower side is tracking the straight end cut. The filing can be done with smooth strokes, much like shooting pool. If you do not lift the #0 cut file from the bevel your angle will be more accurate. The brass is much softer than the file so it doesn’t damage the file to use both forward and backward motions without lifting the file from the metal. The file actually only cuts on the forward motion. Doing this procedure on steel is not recommended because it will dull the file. The easy way to accomplish this is to file one end and flip the piece over so the other side can be beveled. Even though lap seam joint is more difficult than a butt seam it has some major advantages with strength and accuracy if the seam is longer than an inch. Another benefit is the seam will compress and get tighter when hammered. The butt seam on the other hand spreads as it is hammered and the seam widens.
Before you bend the bracelet into a circle you need to saw small tabs on either side of the bottom end. Mark the outside of the bracelet so the lower side becomes obvious. Using a fine saw blade 4/0 or finer cut lines in the ends about 1.5mm to 2mm from the edge. Cut past the bevel line by about 1 mm. Try to design the bracelet blank so the tabs will be cut off later, making a cleaner seam line. This seam is very useful for box and hollowware designs as it will work on pieces up to foot long and keep the seam even.
Form the bracelet into a circle over a stake or bracelet mandrel. Then take parallel flat pliers and make a flat area about 6-10 mm from the ends. This will make a nice shelf for the solder and make the piece stable while soldering. While the ends are still apart, bend the tabs up slightly to form stops. Bend the two ends past each other so they become springy. This will make it possible for the two beveled sides to come together correctly. Pinch the seams tight with the parallel flat pliers to lock the sides together. An alternate method is to tap the tabs down with the flat side of planishing hammer over a flat T- Stake.
The piece needs to be in a stable position while soldering so the metal doesn’t warp when the intense heat is applied with a torch. Place the project between two kiln bricks with only the corners touching so the bricks don’t absorb too much heat. This will keep the form from collapsing into an oval and losing the seam tightness. If you have a lapidary or diamond saw, cut the bricks into small cubes for easier handling in the annealing pan. The small pumice rocks make a good support system while the heat is reflected around the solder joint. Use plenty of white Handy Flux or an equal mix of borax and boric acid to keep the hard silver solder clean from oxidation while soldering. A solder pick is very useful to keep the solder pieces in place. For long seams, 20 gauge wire solder is useful cut in 4-5 mm lengths. The wire solder tracks nicely into a straight line with the lap seam. A lap seam will require more solder than a butt seam as it has a larger surface area to fill. If this project is done with very heavy sheet metal you can twist the wire solder with a drill into a spiral rod. This will add solder volume for the length of the seam.
The seam needs to be soldered once with enough solder to do the job. All traces of extra solder have to be removed. It is possible to do the job with needle files but the flat #2 rifle file works better. The reason is that the working surface touches just the area to be filed. A straight file is hard to work on a flat surface without removing unintended areas. You only need to remove solder. The goal is to have as thin a solder line as possible.
To make the seam and the surrounding metal the same gauge it is necessary to compress the seam so it blends away. Use a raising stake (R-101) or a stake that has the same curve as the bracelet. Hammer with the rounded side of a heavy planishing hammer (HMR-101) or something similar so the metal gauge feels the same thickness through out. The round side of the hammer is used because it is very easy to make “half moon” marks with the flat side as you hammer a flat surface. File the outer edges of the bracelet so they are not ragged.
Round the bracelet at this stage on the raising stake (R-101) or a bracelet mandrel. Use a non-marring hammer (HMR-107) flat end. The horn of an anvil would be another option. A regular steel planishing hammer is an option but these marks will have to be removed in future steps. After each full hammering of the shape, or a course, the metal needs to be annealed to bring it back to a soft state for next round of forming.
Embossing or doming a bracelet from the inside with hammers will thin the bracelet as it is stretched. The other way is to raise the metal towards the middle of the form. If this is done correctly, the edge will not stretch, but compress and thicken. Raising from the outside is a very useful technique to know because some closed forms are very hard to emboss. The mushroom insert stake (M-111) is held in an extension arm stake holder (T-101). The extension arm stake holder (T-101) was in turn held in the Stake Holder (VH-101) mounted in a large vise. Another holder is available to mount on a heavy work bench or stump (not shown, H-101). A simpler set up would be to hold the mushroom stake (M-111) in an extended holder (H-1L Holder) on a jeweler’s bench. The primary curve of the mushroom stake (M-111) fits exactly into a two inch circle which is perfect for bracelet forming. There are advantages in the multiple holders and they will become apparent. The metal is formed on the mushroom stake (M-111) and will take on the curve of this stake as the process proceeds. The actual raising is done with the flat crosspein with a nylon end (HMR-107, #9 end), wood or Delrin face. Start the first course line about 8 mm from the edge. It is important to have an air gap between the metal and the stake. The metal under the hammer is compressed down to the stake with overlapping hammer blows. As the metal is compressed the outer edge will start to ripple if the raising process is too aggressive. The nylon ends are useful as they compress the metal like a steel hammer but don’t texture or stretch the metal. Stretching with a steel hammer will happen once the metal reaches the stake and the hammer continues to hit the same spot. Using a steel hammer is a traditional option that requires the smith to both feel and hear the metal becoming firm against the stake. When this happens it is time to move one hammer width around the form. Both sides of the bracelet need to be raised and then it is time to anneal again. The raising process will take between two and three courses until the metal conforms to the stake.
The bracelet has been made to fit the mushroom stake (M-111) and now it is time to transform it with fluting. The first fluting stake is the peaked mushroom stake with a rounded edge (M-113A). This stake has a primary curve that matches the forming mushroom insert stake (M-111). The M-113A is actually the M-113 stake with a regrind that makes the crest or top curve into a medium sharp peak. You could also grind this shape from steel bar stock. The peak is ground with two angles so Side #1 is less sharp than Side #2. Side #1 will form shallow flutes and side #2 will form deep flutes or flutes very close together. By rotating the T-Holder (T-101) to face at right angles to the vise mounted holder (VH-101) the project will then face straight out for fluting. The fluting will be done with a T-Holder (T-101) position that is right angle to the raising process. If using a H-1L holder mounted to a workbench, you will have to swing your chair around to do the fluting. If your holder is mounted on a wood block (VB-1), just rotate the block in the vise.
The maker needs to mark the bracelet with the desired flutes with a thin black marker. Because the forming may require a few courses and the lines will disappear during annealing, it is necessary to establish more permanent reference points. This is done with a saw frame and thin blade by nicking the edge of the form with a small notch. These marks with keep the flute layout from wandering during the forming process. A small triangle needle file could also be used. If the flute lines are straight, a straight rounded crosspein hammer (HMR-2’s thinner end) may be used. If the flutes are slightly curved then a crosspein with a rounded face will be necessary to follow the ink lines. Because the curved flutes look correct with a free form shape, the rounded crosspein hammer (HMR-9) with the narrower face is selected. The hammer blows fall on either side of the black lines with an air pocket about 2-3mm between the bracelet metal and the stake. As the hammer strikes the metal the stake forms a line inside the bracelet. Because this first fluting stake has a rounded peak the inner line will not be sharp. This has the advantage of letting the smith move the line slightly with the repeated hammer blows. The action is actually a double blow. The hammer is driving the metal downward while the stake driving the metal up from the inside. This upward motion is called snarling and is actually a type of embossing. There are special stakes called snarling irons and they will be discussed in a future article. After the line is articulated from one side the bracelet is then reversed and hammered from the other side of the line. This roughs out the first flute and this process continues until the whole fluted area is blocked out.
The non-fluted areas are now refined with the round side of the silversmith’s planishing hammer (HMR-101). This is a full sized planishing hammer and the smith may opt for a jeweler’s planishing hammer (HMR-1) if a delicate texture is the goal. The original mushroom forming stake (M-111) is again chosen as it fits the shape. Working the metal from the center to the edges, the entire surface is covered with even, overlapping marks.
The metal is now work hardened and must be annealed. The second fluting course will follow the same lines so it would be helpful to re-mark the design. If only slightly rounded flutes are desired then the forming would stop with the first fluting stake (M-113A). Our goal is for a sharper peak line so we will switch to the sharper fluting stake (M-113B). This stake is identical to the first fluting stake (M-113A) but the top crest is sharp. Planishing on this stake will bring the flutes up and the degree of flute crispness will depend on how much and how lightly the planishing is done. The second course with the sharper fluting stake (M-113B) depends on having a track to follow that was developed by the slightly rounded fluting stake (M-113A). If the sharp fluting stake (M-113B) was used first there is a strong tendency for the interior line to be choppy and the score line to be ragged. Stop hammering when the desired texture is accomplished. File the edges and emery if you desire a smooth edge. Another finish is to “upset” or texture the edge with a crosspein hammer. This will make the edges to appear thicker and less mechanical. The only remaining step is to polish. If the working hammers are in a pristine condition, the polishing will go very quickly using a finish compound like white diamond on an unstitched cotton buff.