I'm still tuning the new foundry but it's working pretty well now. I did my first real casting with it yesterday. This was also my first full cycle project. Design in CAD, Cut in foam on the CNC router, cast in aluminum.
I wish the finish was a little nicer. Next time I'll take more time coating it with drywall mud and ramming it in sand better.
I fired the three pieces one at a time in the kitchen oven. A couple hours at about 250 to drive out moisture and about 5 hours at 500 fahrenheit. The bottom section developed a small crack. This is the only section that didn't have extra re-bar in it. I didn't add the rebar because this section doesn't move and isn't lifted. I might regret that choice.
The other two came out great. Here they are bolted together.
I've been putting this off for a while because I've been scared of screwing it up. Oh well, nothing ventured, something something something.
I've been thinking about how I'm going to do the refractory lining for the new foundry. Many of the recipes I've found on line call for bentonite clay. The bentonite I've been able to locate is feed-grade stuff sold at agricultural supply places. It's small pellets which I assume have to be dried and ground to a fine powder so it can mix with the other ingredients and coat them. I searched around on the Google an got some ideas for a ball mill. I knocked this together with scrap I had lying around. I still haven't figured out how to drive it. Maybe an old hand drill.
A local place in town made me a great deal on sandblasting and paint for the furnace.
Haven't touched this project for a while. Too darn cold and too many other things going on, I guess. Anyway, managed to get back in the shop, finish the welding and get the frame ready for paint.
I'm using skate bearings for the lift mechanism. I had a bunch left over from building my router and the work really well on the square tube.
I've started building the frame and lifting mechanism. My plan is to have the top lid rotate off for adding to the melt. The top two thirds will lift straight up to remove the crucible from the side to pour.
My old foundry, a gingery style charcoal burner, showed me how much I like casting aluminum. However, it's messy, burns a lot of charcoal, and the lid was breaking down. So I'm going to build a new one. This time I'm going to build a propane burner and spend a bit more time to make it a more permanent tool in my arsenal. I'm basing my design around a foundry built by 'Splint' on CNCzone. The first pic is what's left of foundry 1.0.
I found this old propane tank lying in a neighbor's ditch and she gave it to me. I cut it down to size based on a 3 inch wall and a crucible no bigger than 6 inches in diameter.