casting jewelry...making a mold (part one)

A couple of months ago I took a big step...I ordered a large vacuum casting setup for making jewelry. This was in some way me going back to my roots...my parents bought me a small casting setup when I was 18, that included a small vacuum caster and burnout kiln. Not knowing much about anything, I set it up in our carpeted kitchen on the laminate countertop, sprued up a wax, burned out a flask, fired up the torch, and successfully cast a few pieces of jewelry.

 Jewelcast Casting Machine

Jewelcast Casting Machine

Now being a craft supply hoarder, I never got rid of the Jewelcast casting kit, and I'm really glad I didn't. I wonder why someone is not making this casting kit anymore.  Check it out here.  

But I decided that I would like to cast multiples of some of my jewelry pieces so I can reproduce them quickly and accurately. There is a particular project that I'm working on, and it takes me too long to create a pendant to make it cost effective to sell in a small gallery. The goal is to make it more affordable.

I'm finding that making original jewelry pieces in wax is becoming a lost art.  The goal is to create a piece of jewelry, create a rubber mold, then use a wax injection system to create multiple waxes which can be then cast.

 Original piece with sprue in silicone

Original piece with sprue in silicone

So last week, I created a "master" in silver. Then a "stem" called a sprue is attached, and a rubber mold is made. I wish that I had photos of what happened. The rubber was full of bubbles, and at first I thought that the mold would be unusable. I used the vacuum table on the casting machine to suck the bubbles out, but I was afraid to leave it on for more than about 30 seconds. The resulting mold (left) had a lot of bubbles.

On the second attempt, I mixed the Castaldo ICE RTV mold material in a cup, and I used the vacuum table on the casting machine and left it on almost 5 minutes. Then I poured the rubber into my mold frame. It worked! That gave me the mold that I could use to inject the wax into to make multiples. It was a big step...for me, at least.

And to my surprise, BOTH molds worked just fine. It was recommended on a forum that you make two, so while one is cooling, the second can be filled. Now if I could only figure out how to keep our two black labs' dog hair from sticking to the mold.