Now that the cuttlebone is sanded flat and the mold is dug out you are ready to cast the first step is preparing the silver. The second step is setting up the mold for casting. The third is heating and pouring the silver and then the last is removing the piece. For a quick video demonstration of pouring the metal watch the above video.
Preparing the silver
When preparing the silver to cast there are a few crucial steps. If you have a new crucible make sure to prepare it for casting. If the crucible is ready the first step is prepping the silver, which is selecting the right type of clean scrap. You don’t want to use any scrap with solder on it. Also you only want to use one kind of silver. If you are using fine silver make sure all the scrap you intend to melt is fine silver. If you are using sterling silver make sure all the scrap is sterling silver. I usually keep my dirty silver (silver with solder on it), clean sterling silver and clean fine silver in different bags. This helps with sorting later and can save time.
Take the silver you intend to cast and then measure out the amount you need. Remember you need extra silver for the button. Measuring out silver is a skill that develops over time. It is always better to have a little extra silver because extra silver can just be dumped in water. However, if you measure out too much silver it more heat will be required to melt the silver and keep it melted during the pouring. If you are using a small torch like the one I have the process can be much more difficult or impossible if there is too much silver.
After measuring out the silver run water over it to clean off any paper or glue that might be on the pieces. Then put the silver into the pickle. The hotter the pickle the less time the silver has to be in the pickle. After silver has been in the pickle place it in the crucible. While the silver is cleaning you can start setting up the mold.
Setting mold up for casting
There are two parts to setting up the mold. The first step is to attach the two halves of the cuttlebone together. You take the end with the mold dug out and line it up as tightly as possible with a half that is just sanded flat. The two halves don’t have to come from the same cuttlebone but you need the back plate. Make sure the back plate has a matching buttons, or funnel chute, to make it easier to pour the silver in.
After the two sides match to the point that no light is coming through when you look into the mold, take binding wire and run it around about three times. Then tighten the ends of the wire. The next part is a bit tricky. You need to create a platform to support the mold so that you can pour the silver. What I usually do is take two firebricks and place them on top of a solderite board. Then place the mold between the two bricks. The solderite board is there in case you spill the silver and it will protect your work area.
Make sure to put the bricks close enough that the mold won’t slide down. You also want to make sure that the mold is high enough. If the mold is too low between the bricks the bricks will pull the heat from the mold quickly, which could affect the casting.
Heating and pouring the silver
Now that you have the crucible, silver and mold ready it is time to pour the silver to make the piece. Place the crucible with silver in it on top of a honeycomb or another piece of firebrick. Then place flux within easy reach. If the flux is wet use an eyedropper, if the flux is dry make sure the lid off. Open all the windows and set up a fan to create a cross breeze. I usually only do cuttlebone casts when it is cooler outside because in the summer my apartment will just get too hot.
Before doing anything else put on your safety equipment. For cuttlebone casting I always wear a denim work apron, goggles and mask while applying heat. When I do the actual casting I wear a protective heat glove while holding the handle. This equipment is important because I have had crucibles of silver explode on me and the only reason I am not covered in burns is because I was wearing the apron and goggles.
Next screw on the largest bit for your torch and then light it. Steadily and in circles apply heat to the torch. Don’t put the flame too close to the crucible; if the torch starts to make sucking sounds that means you need to pull it away. Basically resist the temptation to apply the heat directly to the metal. This will not speed up the melting process; applying heat directly to the silver will actually make it take more time to melt. An essential component of getting the silver to the melting temperature is to make sure that the crucible itself is hot enough.
Once the silver is completely melted add the flux. If it is liquid flux just a drop or two, if the flux is dry just a sprinkle. You don’t need a lot of flux, just enough to clean the silver. Once the silver is clean pick up the crucible. I usually wear an Ove Glove when I pick up the handle for extra protection in case the silver spills. Hold the handle for the crucible with your right hand while still holding the torch with your left hand.
Keep applying the heat to the silver and get the flame as close as possible to the mold. Then pour it in quickly in one motion. It is best to pour all the metal at once, if you are quick enough you might be able to pour it twice but it is always better to pour in one motion. Do not touch the mold or the firebrick supporting it. The silver can stay liquid inside the mold, where you can’t see it, for a few seconds and the mold itself is hot enough to burn you from the outside.
Removing the piece
Let the piece fit for a few minutes. As the cuttlebone burns a little bit of smoke will drift and give off a horrible smell. This is part of the reason why you want the windows open to help get the smell out before it takes over. As the piece cools place the crucible back on the honeycomb and turn off the torch. Then grab a pair of wire cutters or sheers to cut the binding wire.
Make sure to cut the binding wire without touching the cuttlebone. Cut the wire and slowly undo the wire. Open the mold over a honeycomb, firebrick or siderite board. Once you have it open use copper tongs to remove silver pendant. Quench it in water and run it under water to remove all ash. Then place the pendant in the pickle for a while to clean.
Hopefully your piece casts perfectly. This will not always happen. Sometime only half the piece will cast or it just doesn’t go any further then the button. The worst is when you don’t measure enough silver and only the bottom half or less is cast. Many times these partial casts can be salvaged. If worse comes to worse you can always he pendant back in the crucible and cast it into another piece. Now that the piece has been poured it is time to finish it and get it ready to sell.
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