Tips and Information about making jewelry



With this blog, I hope to share my knowledge, successes, trials and errors, student's work, tips, and information about making jewelry.

Sunday, April 17, 2016

Annealling Silver or Copper Sheet


Annealing (metallurgy) is the process of heating metal altering the microstructure of a material causing changes in properties. In metalsmiting its used for softening the metal so that it is more pliable, bendable. 

While opening a soup can, have you ever had the lid of a can not cut all the way off and so you bent the lid back and forth until it broke off? This is the process of "work hardening." The processes of hammering, bending, or  compressing metal work hardens the metal. Over working the metal causes it to crack or break. The metal must be annealed before it cracks or breaks and then the work process can continue. 

 Sometimes silver, copper or brass sheet comes already annealed and other times they are sold not annealed or hardened. If the metal is hardened it must be annealed before working the metal like bending or hammering. Annealing makes bending and sawing metal easier.  

Once the metal is annealed it stays annealed until its work hardened. So, if you anneal metal and allow it to sit for years, it is still annealed. Time doesn't harden the metal. 

The process of annealing is heating the metal to a specific temperature either with a torch or in an kiln. With a kiln you can set the temperature but with a torch you must watch the metal until it is a dull red color. The room must be darkened so you can see the metal's color. For beginners its had to see this. There are two easy ways to know when the metal is up to temperature.

  •  Place a dot of Handy Flux in the center of the metal. Heat the metal going from the outside edge to the center area, keeping the flame away from the flux. This heats the metal evenly and as it warms up the flux will dry to a white crusty look and then go clear. When its clear the metal is up to temperature.
  •   Using a permanent marker, draw a dot in the center area of the metal. Heat the metal going from the outside edge to the center area, keeping the flame away from the flux. This heats the metal evenly and as it warms up the black dot fades away leaving a shinny area. At this time the metal is up to temperature. 

 
Here are the complete steps:
  1. Apply either flux or permanent marker to the metal.
  2. Heat the metal with a torch holding the torch perpendicular to the metal. Don't hold the torch angling it across from the front edge towards the back edge! This doesn't heat the metal evenly. 
  3. Slowly move the torch across the metal going from the outside edge circling in towards the center. If you move the torch fast, it doesn't heat the metal evenly. 
  4. After the marker or flux fades, pick up the metal with tongs and quench in water. 
  5. If needed clean the metal in pickle and then rinse.
Here is an interesting note, no pun intended. If you drop the work hardened metal onto a table it has a high pitch tone to it. Consequently, the annealed metal has a lower pitch tone!

Friday, March 20, 2015

Tips to Know About Jeweler's Sawblades




Saw blades are measured in size by numbers that are like the numbers on a number line. There is no zero size saw blade. Just like the number line, as the number goes up the size of the blade goes up. As the number goes down the size of the blade becomes smaller.

Two saw teeth to the side of metal
The smaller the blade the thinner it is and the more teeth per inch. The larger the blade the thicker it is and it has less teeth per inch. The correct saw blade size should be measured by the amount of teeth to the side (thickness) of the metal. There should be between
2 -3 teeth to the side of the metal.

The jeweler's saw blade attaches to the saw frame with the teeth pointing down and out away from the handle. The thicker the metal, the larger the blade needed. The thinner the metal the smaller the blade needed.


An annealed saw blade
More expensive blades pay for themselves because they don’t break as easily as less expensive blades. The more expensive blades are annealed so that they bend more without breaking and they have a rounded back allowing the blade to turn more easily.

If the blade is too big, you will have a harder time pulling the saw blade down through the metal. The metal may even bend from the force. If the blade is too small, it won’t steer where you want it to go. It tends to go where ever it wants! Size 05 - 03 are the saw blade sizes used the most.

Saw frames come in several widths (throat depths). The depth allows for sawing deeper into a sheet of metal. For the most part, 3”- 4” is plenty deep for most sawing needs.

Wednesday, December 31, 2014

Can Fine Silver Really be Work-hardened?



A question was asked online about how to work-harden fine silver. Someone had embedded fine silver wire into metal clay earrings and they wouldn't hold their shape. There was quite a bit of discussion on work-hardening fine silver.

I researched the answer and found this information.

What is a metal's hardness?
A metal’s range of hardness differs depending on its particular mixture due to its arranged patterns of crystals and concentrations of mass specific to that metal. Each metal type has a range of hardness from soft to hard only relative to that metal. In other words, each metal type has its own range of soft to full hard ratings. 

How is a metal's hardness measured? 
There are several tests developed for measuring hardness, Mohs, Vickers, and Brinell. Through research, I found that Vickers is most often used for measuring a metal's hardness because it has one of the widest scales among hardness tests, known as the Vickers Pyramid Number (HV). The Vickers test observes the metal's ability to resist plastic deformation from a standard source.

When comparing relative hardness, Vickers lists fine silver as having the most softness compared with sterling silver and argentium silver. It rates fine silver as the softest metal when it is fully hardened when comparing it to argentium silver and sterling silver. Even at full hardness fine silver is still softer than soft sterling silver.


For earrings, the metal must be work-hardened so that it holds its original shape and can spring back into its original shape when slightly bent. Work-hardened fine silver still isn't able to become work-hardened enough. This is why copper is added to fine silver, making sterling silver, so that it can be work-hardened until it is spring-hard.

So, use sterling silver in your metal clay earrings in order to gain the needed spring-hard hardness. Make sure you don't fire the sterling silver higher than 1300˚F (704.44ºC) or the metal becomes brittle.

There are a few ways to work-harden sterling silver.
  • Hammering the sterling silver with a rawhide or plastic mallet against an anvil
  • Twist sterling silver wire (posts) with pliers or compress them with pliers
  • Heat harden sterling silver in a kiln

According to Jörg Fischer-Bühner from Santa Fe Symposium® Proceedings, 2003. These are the steps for heat hardening sterling silver. 


Step 1: Check the sterling for any solder joints that may already be present.
Step 2: Heat the sterling to 1292°F–1346°F (700°C–730°C) for 30–60 minutes; adjusting temperatures if solder is present (if low-temperature solder is present, heat the piece only to 1000°F–1200°F). Quench in water.
Step 3: Heat the sterling again, this time to 572°F (300°C), holding at that temperature for 30–60 minutes. After cooling, Vickers hardness will range between 120–140dph; if lower temperatures are used, the sterling will not achieve this level.

Friday, September 12, 2014

Testing Your Kiln's Temperature


by Janet Alexander





 Now that most kilns have a computerized controller it’s become easier to control the kiln’s temperature. But, is the controller’s readout accurate? With so many varieties of bronze, copper, and silver metal clays, it has become important to know if your kiln’s temperature reading is correct. Otherwise, you may have problems with the clay not sintering correctly or getting too hot and melting. Additionally, the kiln should be tested for hot spots and cooler spots. Every kiln is different.





Testing can be done by using a pyrometer (which is how I used to adjust my kiln’s temperature before there were controllers) or by using kiln pyrometric cones. The pyrometric cones are supposed to bend when heated to a specific temperature for a certain amount of time. That means that pyrometric cones give a temperature equivalent; they are not simple temperature-measuring devices. According to a pyrometric cone manufacturer, cones have over 20 variables that can affect the cone’s bending, including the cone's composition, particle size of raw materials, type of forming process, moisture during forming, density of the cone, geometry of the cone, setting height, and angle and the heating rate. Atmosphere also affects bending behavior. Wow, that’s a lot of variables!  So, let’s look at testing with a pyrometer or a kiln test kit.

I used the kiln test kit sold by the PMC Connection. According to experts, the average kiln controller is accurate to ±10°F (±5.5°C) so keep this in mind while testing. Additionally, run the test several times but move the thermocouple to different areas of your kiln. Place it towards the back, near the front, off to each side, and etc. Test at different temperatures. I conducted tests at 1110˚F, 1200˚F, 1290˚F, 1470˚F, 1560˚F, and 1650˚F. I found that both readouts were within a few degrees of each other until the temperature got up to 1650˚F. Then they were off by 10˚F! So, I added another thermocouple from my casting kiln.  All three read different degrees but were within the accuracy range.

Now I know why my PMC3 clay had a crystalline look to it when I fired it at 1650˚F; it was getting too hot! So, now I lower the temperature of my kiln by a few degrees when setting it at 1650˚F.


The Test Kit Includes:
  • Sensor  reader (tester)
  • 9V Battery 
  • K-type thermocouple TP-02A  
  • K-type thermocouple TP-03 
  • Case 
Use the TP-02A thermocouple (larger one) for testing your kiln. It has a temperature measuring range of (-58˚F to 1650˚F).



The Steps

1.  Install the 9 V battery into the unit’s back.












2.  Insert the plug into the bottom of the sensor reader making sure the plug’s polarity matches with the sensor’s polarity. 











3.  Insert the thermocouple into the kiln.












Caution: Don’t insert it past larger ceramic end or the wires will burn!












4.  Place the thermocouple near the kiln’s thermocouple for the first run of testing.







5.  Turn on the kiln and set it to hold at the test temperature for at least 15 minutes.

The sensor reader can read in Fahrenheit (F) or Centigrade (C). Turn it on by sliding the button from the center (off position) to the F (if measuring in Fahrenheit).








6.  The sensor displays its reading. Allow it a minute to stabilize to the temperature. Test at various temperatures. I found that my kiln was accurate until it reached over 1350 (F).









7.  When finished testing, turn off kiln and sensor reader and allow the thermocouple to cool before touching it.






Sunday, September 7, 2014

Vibratory Tumblers

How is the Tumble-Vibe different from a rotary tumbler?

The basic difference between a vibratory and a rotary tumbler is the way the unit is driven.  A rotary tumbler consists of a barrel that sits on rollers causing the barrel to spin. Polishing media and the objects to be polished (jewelry pieces) are placed inside the barrel. As the barrel spins, the contents fall and slide over each other causing abrasion or polishing to the jewelry pieces located in the top 1-inch of the sliding media.  Jewelry pieces not located in the top inch are not polished. Some items can become dented due to the polishing media falling on the jewelry pieces.  It can take hours, days or weeks to bring a piece of jewelry up to a high shine using this type of unit. The lid on the barrel can leak or come off during the process.
 
A vibrating tumbler includes a bowl that sits on an out-of- balanced motor. As the motor moves, it causes the bowl to vibrate in all directions. The polishing media and jewelry pieces are placed inside the bowl. The bowl’s vibration causes the objects in the bowl to rotate around the bowl in two directions rubbing and polishing the jewelry 100% of the time. The items are polished much faster than a rotary tumbler and there is no chance of leaks, spillage, or denting of pieces. The items can be easily retrieved by opening the lid and fishing through the polishing media.

 A variety of different media, from cutting, to polishing, can be used in the vibratory tumbler including ceramic and plastic abrasives, walnut shells, and steel shot, making the vibrating tumbler more versatile than a rotary tumbler. The ceramic and plastic abrasives are sold in different grits. Polish is embedded in the walnut shell with the same polish jewelers use on buffing wheels. Steel shot, due to its hardness, is used as a burnisher. As it moves across the jewelry it rubs and burnishes the outer layer of the metal. 


General Instructions for the Raytech TV-5 Model
  • The working capacity* of the Tumble-Vibe 5 is approximately .05 cu. ft. (three pints) or 4 pounds. The capacity includes the media, water and the work pieces.
  • If the tumbler will be used for polishing as well as for cutting, always reserve one bowl strictly for the polishing media so it can remain free from embedded cutting grit.
  • Successful finishing of most jewelry requires preparing the jewelry. Parts must be filed, sanded, or ground smooth over rough areas. Attempting to finish jewelry parts without adequate preparatory finishing can result in very long finishing cycles and loss of detail in the jewelry pieces.
  • All plastic media or ceramic media should be broken-in before using. Media that is not broken-in may cause scratches. (See separate section, below, for breaking-in plastic media.)
  • Keep a 70% media to 30% jewelry ratio. Too many items tumbling at one time can produce a poor finish.
  • Always use cutting/burnishing soap with the media as required.
  • If using steel shot, fill the bowl with water so that it just covers the top of the shot. Never completely fill the bowl with water. Too much water or soap hampers the media’s action. After tumbling, remove and dry shot.
  • If using plastic or ceramic media, add 1 ½ oz. of water and a ½ teaspoon of polishing compound. Note: if the machine does not roll the media well at the start of a cycle, there is too much water or soap.
  • Change water if it becomes gray or loses its suds. Rinse the bowl and clean the media.
  • If the media tumbles too long without replacing the water, the jewelry pieces will absorb the gray sludge which is very hard to remove. The manufacturer recommends changing the water every three hours.
  • When using ceramic media, don’t allow the bowl to run dry. This will cause premature wear on the bowl.
  • Walnut or other shell media do not require water. Fill the bowl ¼” below the center cone and jewelry items.
  • On average, dry polishing media is good for polishing up to 200 hours of use. When not in use, store in an air-tight container. See manufacturer’s instructions.
  • Do not use media filled with silicon carbide or alumina powders as this will impinge and impregnated the metal surface and retard polishing.
NOTE: THE TV-5 UNIT CAN BE USED WITH UP TO 4 LBS. OF STEEL SHOT/CERAMIC MEDIA AND JEWELRY.

Breaking-in Plastic/Ceramic Media
1.   Place media into tumbler bowl.
2.   Add water and polishing compound /soap.
3.   Tumble without jewelry for one to two hours.
4.   Rinse media and bowl. Rinsing the media in a colander works well.

Thursday, September 4, 2014

No More Maring Your Metal While Holding it in a Vise

All jewelry tools are made smooth without teeth so that they don't mar the finish of your work. But, sometimes it's helpful to have a vise with gripping teeth to hold various objects.




If you buy a bench vise at a discount store, it's not necessarily made for working with non-precious metals while making jewelry. You may need to smooth it in order to hold a piece of soft silver without marring it. So what do you do?









To solve this problem and have the best of both worlds by covering the jaws of your vise grip with copper sleeves.
  1. Anneal the copper to make it malleable.
  2. Cut two pieces of copper with the following dimensions: Width (equal to the width of the jaw) x Length (twice the height of the jaw).
  3. Place one copper piece into the vise closing it tightly.
  4. Using a rawhide mallet, hammer the copper down over the top of the vise.
  5. Repeat the process with the other copper piece. 
Viola! You have a nice smooth surface inside the vise. When you need to use the vise with teeth, remove the copper.

Friday, August 22, 2014

11 Tips for Creating Bezel Settings for Cabochon Stones


Cabochon stones have a flat bottom with the sides rising up into a dome on the stone’s top. They are cut into a convex shape. There is a 90˚ angle where the bottom and the sides meet. The first 1-2 mm up the sides are at 90˚to the bottom and then the stone starts to curve over forming the dome.



The bezel setting holds the stone in place by coming just above the flat sides and folding over them right where the stone starts to curve into the dome.

The bezel is made of thin fine sliver wire.  Bezel wire comes in several heights and styles from plain to decorative.


When working with metal clay, the bezel wire can be embedded into the clay before sintering or it can be soldered on top of the metal clay after sintering.

Tips for Embedding Bezel Wire Into Unfired Metal Clay
  • Make the clay base the bezel is being pressed into at least five cards thick. If using PMC Sterling silver metal clay, make the base six cards thick, allowing for the extra shrinkage rate.
  • Choose the right bezel height. Allow extra height for 1mm of the bezel to be pressed into the metal clay. If the bezel is too tall, thin cardboard can be placed in the setting to raise the stone to the proper height. If cardboard can't be used (due to an opening in the base) then the bezel wire can be filed down to the proper height.
  •  Fit the bezel so that the stone fits loosely inside of it. This allows for slight deformation while sintering.
  • Cutting a hole in the base metal clay inside the center of the bezel helps keep the clay from warping while sintering. Allow for at least 4mm distance from opening to the bezel wire.
  • Filling the bezel with casting investment (the same material as ring plugs) helps keep the bezel from deforming during firing. If you have an opening in the bottom of the bezel, cover it with kiln paper and then pour the investment into the bezel filling it just below the bezel's top edge.
  • Adding decorative syringe or clay work around the outside of the bezel wire helps hold it to the base. 
  • Coating the bottom edge of the bezel wire with oil paste makes the join more secure.

Tips for Soldering a Bezel on Fired Metal Clay
  • The fired metal clay must be burnished in the area where the soldering takes place in order to close the pours of the porous metal clay.
  • Use sterling silver solder either, hard, medium, or soft.
  • If there is texture in that area, it must be smoothed in order to obtain a flush soldering join. It's best to smooth the area while the metal clay is in its dry stage. 
  • The metal clay's shrinkage must be accounted for so that the bezel fits the sintered metal clay. Create a drawing of your design in the finished size, including the location and size of the bezel. Scan the drawing and then print it larger according to the shrinkage percentage of the clay you are using. Use the enlarged drawing as your template for making your metal clay piece. It also allows you to know where not to have texture! Here are the percentages of enlargement for some of the different metal clays.
    • PMC3 and PMC+ shrinkage after firing at 1650F for 2 hours is 15%.  Enlarge the drawing on the printer/scanner by 118%.
    • Art Clay Silver - low fire shrinkage is approximately 9%. Enlarge the drawing on the printer/scanner by 110%.
    • PMC Sterling shrinkage is 15 - 20%.  It's best to err on the large side, so plan on the 20% shrinkage rate. Enlarge the drawing on the printer/scanner by 125%.