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Bronze-Irminsul

Irminsul pendants are available in ancient bronze now. Before, any pendant that needed a bale was a problem because I had no source for ancient bronze bales, now I have a rolling mill and I just make them.

I sculpted a 7″ tall model of a Skane style Mjolnir out of polymer clay the other day. There are too many undercuts in it to duplicate using the sand casting technique, so I will be making an RTV silicone mold and casting it in resin.

I am planning on finishing it to look like either silver or bronze, and possibly, maybe, stone.  It’s going to be flat on the back with a hanger to mount it on the wall.

 

The resin and mold-making material is on its way. I should be able to start producing these in a few weeks.

New Wax models for pendants and possibly pins.

 

There are two new designs soon to be available at whirling sun. One is the Kolovrat, a Slavic sunwheel symbol. The Other is the Germanic Schwartze Sonne, or “black Sun”.
The Kolovrat (lit.: “turning wheel”) was  present in pre-Christian Slavic mythology. It was dedicated to the sun god Svarog and often called “The wheel of Svarog.”

I had attempted to carve the black sun a number of times in the past with unsatisfactory results. There is a lot to it and I could never get the geometry just-right. This time I used a combination of the lathe, the rotary table, and several hours of hand carving; I am happy with the result. Molds are being prepared already.

I know several of my good customers have been asking about these two pendants for quite some time. I am very pleased to finally be able to offer them.

 

 

The black Sun

The Schwartze Sonne or black sun symbol.

 

Kolovrat wax carving

Kolovrat The wheel of Svarog

Still warm Thor's hammers

The Lost Wax Process

Part 4: Casting the Metal

 

Once the flask has matured in the burnout oven, it is time for the fun to begin: injecting it with glowing hot, molten metal!

The centrifugal casting machine has a spring driven arm that holds the hot flask and a crucible that contains the molten metal to be injected into the flask. The arm of the machine “breaks” near the crucible end to help keep the metal in the crucible as the machine accelerates up to speed. The other end has adjustable weights to help balance the machine. The heavy spring inside the base provides the centrifugal force that  forces the molten metal into the flask.

It is important that the flask be just the right temperature for casting. If it is too hot, the metal will not cool and harden and will just flow back out. If it is too cool, the metal will solidify too quickly and form a clog inside the mold.

With the burned out flask simmering in the oven at the correct casting  temperature for whatever metal is to be used, the centrifugal casting machine is prepared for launch. It is important to bring the flask to just the right temperature for casting. If it is too hot, the metal will not cool and harden and will just flow back out. If it is too cool, the metal will solidify too quickly and form a clog inside the mold.

A centrifugal casting machine
A typical centrifugal casting machine for casting jewelry
Centrifugal casting machine with flask

A centrifugal casting machine with crucible and flask in place ready to cast sterling silver Thor's Hammer pendants.

A centrifugal casting machine with crucible and flask in place ready to cast sterling silver Thor’s Hammer pendants.

The metal to be cast is weighed out and placed into the centrifuge’s crucible. The right amount of metal is determined by weighing the wax model multiplied by 10 for silver, or 13 for gold. Then add 20% for the “button” – a reservoir of metal for the casting to draw from as it shrinks.

 

A vial of sterling silver casting grain 

A vial of .925 sterling silver casting grain

The grain is placed into the crucible and then melted using an oxy/acetylene torch. A small amount of flux is sprinkled onto the metal to help clean it. Its heated until it turns glassy and rolls like mercury and then the arm of the centrifuge is released, spinning the metal into the flask.

After the machine comes to a rest, the hot flask is removed from the cradle of the casting machine and plunged into a bucket of water. The thermal shock causes the “investment” to explode, releasing the metal casting inside.

Still warm Thor's hammers

These Thor's Hammer pendants are still warm after being cast. They don't look like much but they are solid sterling silver waiting to be polished up.

 

The casting is done, and all that’s left is finishing and polishing.

 

 

Burnout oven

The Lost Wax Process

Part 3: investment and burnout

 

Once wax duplicates are made from the RTV mold, they are ready to be sprued onto the rubber flask base. The rubber base has a raised cone in the center. This will form a funnel in the prepared mold and also creates a reservoir of extra metal (called the button) to fill the mold.

The wax models can be attached directly to the base, or attached to a sprue, which is melted onto the rubber base, forming a “tree”.

Next a stainless steel tube is placed around the rubber base and the mold is ready to be “invested”.

 

Sprued wax models prepared for investmet

Sprued wax models prepared for investmet

 

Sprued wax models prepared for investment

The investment is a plaster-like powder that is carefully mixed using precise ratios of water to powder. It is vacuumed until it boils,and one minute thereafter, then carefully poured into the prepared flask. Then it is vacuumed again to make sure no air bubbles remain clinging to the wax model. It is left to dry for at least 2 hours.

Once the investment has set, it is time to begin the “Burnout”. The flask is placed into a special oven, nozzle down, and the temperature is gradually increased over the course of hours to cure and temper the investment in preparation for being injected with molten metal.

The oven is preheated to 300 degrees and the flasks are placed in for a few hours, then the temperature is raised to 700, then 1350 degrees, finally the temperature is brought down to the proper casting temperature for the metal to be cast.

 

Burnout oven

Three invested flasks inside the burnout oven

 

Three invested flasks inside the burnout oven
 

Burnout oven pyrometer

The Burnout oven pyrometer at burnout temperature

 

The Burnout oven pyrometer at burnout temperature


Wax copies produced from the RTV mold

The Lost Wax Process

Part 2: Duplicating the Master

 

Once master wax model has been created, it can be “invested” in plaster and burned out to create the void into which metal can be injected. The wax master will be gone forever, replaced by silver or gold or bronze. But what if you wanted to make a few of the same piece?

A new master doesn’t have to be carved for every identical piece you want to create. Instead, a rubber mold is made from the master. This rubber mold can be filled with wax over and over to create hundreds of duplicates of the same piece.

What follows is the method preferred at Whirling Sun: RTV silicone.

First, a wax sprue is attached to the master. Sprues are attached by heating a tool over a flame and “welding” the sprue to the wax  master model with it. The sprue should be thick enough to form an adequate channel through which the hot wax can be injected. It should also be placed strategically so that no detail is obliterated by it. This sprue will probably also be used when it is time to inject molten metal into the casting flask, so it is good to make sure the metal will have a path that is clear of turbulence or right angles. It is bad for metal to be injected through a small opening into a big one, like an hour glass. This causes the metal to “spray” into the cavity like putting your thumb over a garden hose, and can cause a “blowout”. More sprues should be added to avoid this.

The sprued master is then attached to a cone in the bottom of a mold frame.

Wax masters of thors hammers sprued onto mold frames

 

Once the mold frame is ready, a batch of RTV silicone is prepared for it. RTV stands for “Room Temperature Vulcanizing”. As the name implies, it does not require heat to vulcanize, such as natural rubber would. Such heat would melt and destroy a wax model. RTV comes in 2 parts, the rubber and the hardener.

RTV is usually mixed in a 10/1 ratio by weight -ten parts rubber to one part hardener. It is thick like warm taffy and is a bit tiring to mix, but you should mix it with a spatula or putty knife until it is all a uniform color.

Once mixed, it is placed under a bell jar and vacuumed for 5 minutes to release all the entrained air bubbles. After this it is slowly poured into the mold frames, being careful not to knock the wax model off its sprue. Next, the RTV filled mold frame is placed under the bell jar and vacuumed for 5 more minutes. It will most likely boil over during this operation, so it is advised to wrap masking tape around the top of the mold frame to contain as much RTV as possible. a plastic container lid under placed under the mold frames during vacuuming can catch the spilled rubber so you can pour it back in.

 

Mold frames containing wax models and RTV rubber being vacuumed in a bell jar

Mold frames containing wax models and RTV rubber being vacuumed in a bell jar

 

Mold frames containing wax models and RTV rubber being vacuumed in a bell jar

After the vacuuming is complete, the pressure is released and the overflowed rubber scooped back into the frame. The Rubber takes around 24 hours to vulcanize. The process can be accelerated with heat, but remember, there is a wax model in there!

After the rubber has cured, it is time to remove the mold from the frame and cut the model out of it. Working slowly and deliberately, an incision is made around the entire perimeter of the mold using a hobby knife or a scalpel. Next, zig-zag cuts are made so that the 2 mold halves will line up again later. When the wax model is reached, special care is taken to ensure it is not cut. The rubber is pulled apart to gain access while cutting out the model.

 

Finished mold for the Skane Mjolnir

Finished RTV mold of the "Skane Mjolnir" Thor's Hammer pendant

 

Finished RTV mold of the “Skane Mjolnir” Thor’s Hammer pendant

Finally, the mold is held between two metal plates and the opening is pressed onto the nozzle of a wax injector. The wax injector is pressurized and filled with molten wax. The best results are achieved when the temperature and pressure are at the lowest possible settings where the wax still flows and fills the mold. Too hot and the wax will shrink as it cools. Repeat this over and over to create duplicates of your wax masterpiece.

 

Wax copies produced from the RTV mold

The wax copies are perfect reproductions of the original master.

 

The wax copies are perfect reproductions of the original master.

wax-irminsul

Part 1: Creating the Wax Master

Take an inside look at how a piece of jewelry goes from an idea on paper to a piece of wearable art!

 

In this article we will walk you through the process as a piece of jewelry transforms from an idea on paper to a piece of finished jewelry.

It all starts out with an idea and a sheet of paper. In this example, we are going to make a wax master of the Irminsul to be used for pendant and pin castings.  The image can either be hand drawn or printed from a computer illustration. It is then glued onto a piece of  “carving wax”, a specially formulated wax that carves easily and can be burned out completely and cleanly from a mold cavity. Ordinary white glue works well to glue the paper to the wax.

Irminsul image glued to block of carving wax

Next, the outline of the image is transferred onto the wax by poking holes along the lines with a pin, scribe or a hobby knife to form a sort of pointillism image on the wax (Think “connect-the-dots”). This will be the guide by which the piece can be carved.

The paper is then removed and the rough shape carefully sawn out of the wax block. It is sawn out using a jeweler’s saw, close to the line, but not on the line. The final millimeter or so will be carved down with files.

The outline of the piece is cut out using a jewelers saw.

A piece of carving wax after the image has been transferred onto it (using pointillism) and the perimeter is cut out.

 

Next, tools like hobby knives, files and wax carving tools (these are very similar to dentist’s tools) are used to carve the details in.  The shape of the wax master can be formed either by carving away the rough shape until the finished piece is achieved, or globs of wax can be melted and applied to the master to build up the form you want.

Alternately, a wax pen, , a device a lot like a soldering iron but with sensitive heat control can, be used to perform many of the carving operations.

 

The finished wax master for the Irminsul

The master model is complete and ready to be made into metal.

When the details are carved in or applied onto the piece, it can be polished by gently rubbing it with a felt polishing wheel. This step is optional as the final polishing can be done on the finished metal jewelry piece made from the master without risking damage to the delicate wax sculpture.

Another option, only for the brave, is called flame polishing; this is where the finished wax master is passed near an open flame to melt the surface for a fraction of a second, smoothing it. This method usually results in a loss of the sharp details that have been painstakingly carved and risks ruining the whole piece altogether.

 

The wax master featured in this article was used to make several popular items on the WhirlingSun store.

open

Since the lost wax process is complicated, potentially hazardous, and requires a lot of expensive tools to start with, I decided to do another tutorial. This one lets you start out with a bare minimum of equipment and still create stunning results.

Sand Casting

To get started sand casting, you will need the following:

  1. Casting sand (available at www.riogrande.com )
  2. A 2-part box (called the cope and drag) or a commercial sand casting frame
  3. baby powder or jewelers talc
  4. Pewter
  5. A hand held melting crucible
  6. A blowtorch with either MAPP gas or Propane
  7. a rolling pin or dowel
  8. A screen helps

First, you need to come up with some sort of 2-piece frame. I made mine from wood scraps and elmers wood glue. Notice the posts glued to it to assist with alignment. These are absolutely essential and must hold the frame from wobbling around at all. It is also a good idea to mark the sides of the frame with arrows to ensure the 2 parts realign exactly each time.

The part of the frame without the posts sticking up is places face up on a smooth surface. Clumps of casting sand are pressed into it like clay. (it is very much like clay). Press hard with your thumbs to ensure there are no voids and the clumps are pressed into one continuous slab.

When the frame-half is full, use a rolling pin or dowel to roll the surface smooth and flat.

Assemble the second half of the frame (the one with posts) onto the bottom you just filled with sand. Next, place the original model you want to copy on top of the sand, detail side up. When selecting you model, be sure it has no undercuts (such as a mushroom) or else the original will break the sand when you pull it out. Things like pins, brooches, belt buckles and pendants are ideal for this process. If the object has detail on both sides, simply press it into the sand halfway (but put powder on it first!). I opted to use a viking era flyfot ornament for this tutorial.

Next, sprinkle some baby powder (or jeweler’s talc, which seems like nothing but expensive baby powder to me) over the original and the sand. Using a very soft paint brush or a make-up brush, spread it around and make sure it isn’t piling up where it will interfere with the design. This is important and if you forget to add the powder the 2 parts of the mold will stick together.

Use a piece of screen and sift the sand on top of the prepared model. Once it is completely covered with a layer of sand, pack it down with you thumbs. Then fill the mold the rest of the way with sand and roll it smooth with the dowel just like before.

Now carefully open up your frame. A light tap on the sides helps loosen up the 2 halves. carefully remove your original model. You should be left with a prefect impression of the original.

In an area where it won’t be conspicuous on the finished piece, you have to cut a hole to pour the metal through. In my case, the flyfot has no detail on its backside, so dead center is best. On other designs, you might have to experiment. Just make sure that the hole you make is thick enough to allow the metal to fill the cavity before cooling off. I use a 1/4″ drill bit to poke my hole.

On the outside of the mold, the hole has to have a dimple carved to make pouring the molten metal easier. Just cut out a little funnel shaped dimple with a knife. Then carefully reassemble the frame making careful note of the alignment.

Now you are ready to pour. Get your safety glasses, your melting crucible, some pewter, and your blowtorch and head for a place where thousand degree spills wont be a disaster.

Heat the pewter with the blowtorch until its surface shines like a mirror and just the slightest hint that it is starting to turn red. It should roll like mercury at this point. If the metal is extremely dirty and has a lot of slag floating in it, skim that off with a piece of scrap metal. Then pour it into the cavity of the mold.

Wait a few minutes for it to cool, then pull the mold open.

After you break the piece out of the sand, you have to cut off the sprue where you poured the metal through. Then file the nub down and maybe polish the piece a little bit if need be.

And you’re done.

Viking coin Bracelet

There is a new bracelet in the jewelry section. It  is handmade from six sterling silver replica Viking coins which are painstakingly soldered onto rings and joined together. The coins are high quality reproductions of what actual viking era silver coins looked like. These coins feature a helmeted bust and the name Leif Ericsson.

This bracelet measures 7-1/2″ (19CM) long and closes with a large lobster claw clasp.

Can be worn by either a man or a woman.

If someone needs a bracelet that is either shorter or longer than 7.5″ this can be accommodated by doing a few small modifications.

Link to the Sterling Silver Viking Coin Bracelet

Sterling silver bracelet made from replica viking coins
Hart bur is a cutter that is the exact size and shape as the gemstone.

We have begun producing our own bezel settings in-house. These are the silver (or gold) tubes used to hold a gemstone (like in the eyes of one of the birthstone Thor’s Hammers). So much work was going into fitting the commercially made bezels that it became time and cost effective to make them from raw materials ourselves. This will also help to keep costs down in a market of rising precious metal prices.

To start out, a silver rod, slightly larger than the diameter of the stone it will be setting is selected and carefully straightened. Since we work with a lot of 3mm stones, the material selected is 6 gage wire; about 4.1mm.

 

sterling silver rod to make bezel settings for 3mm emerald

A 6 gauge sterling silver rod is selected as the raw materials to make bezel settings for this 3mm emerald.

 

The silver rod is taken over to the micro lathe and a facing cut is made across the cut end to clean up the part where it was sheared off the spool of wire.

 

Facing cut to clean up end of silver wire

A facing cut to clean up the end.

 

Next the wire is turned into a tube by center drilling and then boring a hole into the end of the rod. The drill bit is held stationary in the lathe’s tailstock chuck and the workpiece is spun at high speed to produce a smooth internal bore. This will provide the clearance for the setting bur to do its work and also will make the bezel hollow so light can pass through it to back-light the gemstone that will be set in it. The diameter of the bore is not critical, as long as there is enough “wall” left to form a step to set the gemstone on. Here a #42 (.096″) drill bit is used.

Boring out the wire to form a tube.

Boring out the wire to form a tube

With the tube formed, the next step is to form the seat upon which the gemstone will rest. This is done with a hart bur. It is a tiny cutter that is the exact shape and size as the stone it is cutting for.  It is held in the tailstock chuck and introduced to the spinning silver tube just as with the drilling operation.  It is plunged in so that the back of the cutter head just passes into the tube. This leaves enough wall above the top of the gemstone to burnish down and secure the stone in place.

 

Hart bur is a cutter that is the exact size and shape as the gemstone.

Hart bur is a cutter that is the exact size and shape as the gemstone.

 

After a light polishing , the finished bezel setting is “parted off” from the tube with a cutter mounted in the lathe’s cross slide. A light filing is all that is needed to remove any burs that might have been raised in the fabrication. It is then ready to be soldered into place on a piece of jewelry and a stone set in it. The whole process takes about 5 minutes.

And what about all the silver that is being cut away? Nothing goes to waste. That is collected together and will later be melted down to be cast into a pendant or something.

 

parting off the finished bezel

Parting off the finished bezel on the lathe.

 

Finished gemstone bezel setting

A closeup of the finished gemstone bezel setting ready to be soldered onto a piece of jewelry.

The bezel soldered onto a piece of jewelry

The bezel setting soldered into the eye of a raven necklace terminal and set with a 3mm emerald birthstone.