Activities on these pages about foundry work are very dangerous. The chances of having a fire, causing injuries, or even dying are very good if you are not careful. I am not a professional foundryman, and will not attempt to disclose all hazards. If you choose to try this hobby, every precaution must be taken to be safe. Remember, a hobby is only fun until you're standing in the middle of the street with your family watching your house burn.
Finally. After almost four-and-one-half years, I cast again. There are some parts that I needed for a steady rest for the lathe, and some gears blanks for change gears. I didn't take any pictures of the mold as I went along, but here are some from the actual pouring.
Here is the crucible straight from the furnace. I skimmed the dross (impurities that float to the top of the molten metal) off while it was still in the furnace, and the dross is in the pan in the back. As you can see, the bottom of the crucible is cherry red. I've placed it on the lid so that I could make sure my grip was okay before I moved it over to the mold.
I'm pouring the aluminum into the first sprue here. When I was making the mold, one cavity didn't come out well. There was supposed to be four castings from this mold, but I ended up with just three.
After poring the mold I poured the excess aluminum into my new ingot mold. I tend to melt a full crucible even if I don't need all of the material for the parts I'm casting. By doing this I can reduce my scrap pile, which is fairly large.
Everything has been poured at this point. You can see how hot the furnace is from the color it's giving off. I'm unplugging the fan and hair dryer to stop the air blast, and getting ready to shut the furnace down. After I am finished with the furnace I put the lid back on and cover the vent hole and tuyere with steel plates. This suffocates the fire, and any fuel that was not completely burned can be salvaged for the next melt.
Here are my treasures. They didn't turn out too bad for the first castings I've made in so long. I need to work on my molding a little bit, but my next casting session did come out better. The casting in the middle has a small depression in it, probably from having a small area of molding sand that was too wet. All I have to do is cut off the sprues and start machining them.
This is all that I cast from the pour. You can see how much shrinkage there is when aluminum freezes by looking at the ingot on the left. When I poured the ingots, the tops were flat. As the metal froze it pulled down on the top as it shrank. The volume of all of these parts is about 110 in3 (cubic inches).
Here are the patterns that I used to mold the castings.
These are the two types of ingots that I make. The ones in the front are 'muffin' ingots from a muffin tin. They are nice because they are small, but the larger ingots will fit in the crucible better (assuming I need a full crucible), and I will be able to stack them on the floor. The ones from muffin tins have to be kept in buckets.