Steam Casting: Do or Die!

Today is the day- CAST DAY! First thing this morning I dug out the clay to see if the sprues survived the investment process. It looked like heaven! Two little black spots indicating the investment found its way between the sprues, and the sprues stayed where they were suppose stay. Yeah! This is a picture of what it looked like.

I took a metal hanger and made a handle for the terra cotta pot that was going to act as the "kiln"

Then I made the kiln, a terra cotta pot wrapped in aluminum foil. I only wrapped the outside. If you wrap the inside, the aluminum melts.

Now it was time to fire it up! I got a little nervous when I noticed the burner, the kiln was sitting on, was turning red hot in color. It looked like it was going to melt. I decided to just keep a close eye on it. If it looked like any part of it was beginning to sag, then I'd lower the temperature. Shortly after I fired up the kiln A LOT of moisture started to drip off the flask. I was a little worried about this because, the investment I used for this flask was "soupy". I kept watching it and slowly I started to see the brown wax coming out. I was expecting some smoke, but I didn't get as much as I thought I would.

Here's a little smoke. I am including this picture because the fact that I didn't see more smoke also added to my nerves. I expected to see more smoke, when I didn't, I began to worry the flask wasn't getting hot enough to melt out all the wax. Uh oh! (The small amount of smoke you can hardly see is on the top right of the kiln.)

Once it seemed like things began to level out, I left Todd in charge to watch things. We had a garden hose and a fire extinguisher close by. The kiln had been on for about a 1/2 an hour and we still had another hour and a half to go.

While he was watching the kiln, I needed to make the caster. This would contain the wet paper towels, that would provide the steam. The caster is made out of a scrap piece of wooden closet dowel and an empty dog food can, I attached the two with a screw and Voila! At this point, I took the three paper towels, lightly wet them, and put them inside the caster.

I carved out a crucible to melt the silver in. I also put my carbon stick and borax near by. I decided to melt a couple of beads of silver to get a feel of the propane torch and learn how the silver was going to melt. It turned out to be a good idea because the torch was a little wild. If I had the flame up too high it blew the shot right out of the charcoal crucible, plus there was a small breeze that made the flame inconsistent. We had to re-light the torch a couple of times. This proved to be good information later down the road.

I took some time to practice going through the steps in my head and then I waited, for about 15 minutes for the burnout to end. While I waited, I decided to visit the daffodil fairies and ask for good luck!

Time to cast! I put my silver, more than I really needed, in the charcoal crucible and started to melt it. I thought it was going melt a lot smoother and faster than it did. I think that was because there was a lot more silver than what I practiced melting, and my torch kept going out even more than before. Luckily, because we expected this, Todd was right there to re-light it immediately. As soon as I got the silver melted I stopped to put some Borax in it, and then heated it just a little more.

With the button standing by red hot, I turned off the kiln and put the flask in position. I put the red hot button to the side of the sprue opening and heated the sprue opening and the silver. The silver slipped into position on top of the sprue openings. Things looked good. It was time to put the caster in action.

I could feel the force of the steam under the caster. I really felt like this was going to work. I kept the caster in place for the recommended five seconds and then took a peak. When I saw the sprue button I began to have doubts it worked. It wasn't evenly round and there was a splash of silver to the side that made me nervous.

While the flask was cooling down for five minutes, I decided to see what it looked like under the caster. I expected it to be really burned out, but it wasn't.

Time to see the results!

The flask reacted the way it was suppose to. The investment boiled out. I reached down into the bucket to get my cast out. All I seemed to have was a sprue button. There was no sprue attached to the button. I began to think the sprues were too small and the silver never made it down, maybe there was too much surface tension? My heart sank! No! really! My heart sank! I reached in again and found the heart at the bottom of the bucket! I couldn't believe it! It casted! I think the paper towels had too much water in them and somehow the silver from the sprue shot back up. I suspect this because the sprue button is slightly hallow underneath. It looks as though air, or steam was forcing the silver back up and out. That's my guess, and it could be way off base. Whatever happened, the heart made it.