Did a bit of modification of the rock tumbler to hopefully protect the canister, and keep it on the rollers! Just a couple 608 bearings should do the job.
Last night I had my first melt. I still haven’t finished the foundry burner, so I just used the weed burner. It did alright, but was probably wasteful. I ended up having to shim the lid up so I could get enough air forced in from the weed burner and the propane bottle started getting pretty cold which is an indication of using quite a bit of propane.
I started pretty slowly bringing the small crucible up to heat, my goal to try to draw out and dry out any water it might have absorbed. Hopefully by going slow we wouldn’t crack the crucible on the first melt. I have two crucibles, this one is the small one that I think I can manhandle with a pair of channel locks, until I build the pouring tongs I need.
I am not sure I can describe the feeling of excitement and nervousness that I had while the foundry was coming up to temp, was I ready for this? Was it going to work with just the weed burner? Did I have enough safety equipment? Was this a dumb idea to pour the small crucible with some channel locks? I took off the lid and things were glowing nicely. I understand why people use sunglasses at this stage now.
I added some small aluminum scrap I have been collecting from computers and misc things to start off, and put the lid back on. Then I added some aluminum extrusions I had picked up at a garage sale a couple of weeks back, it was surprising to watch the extrusions melt through the top and just slowly slide down into the puddle of molten aluminum. Each one might have taken four minutes, I called Jennifer and Jasmine out to watch.
I want to make ingot molds, I have a design picked out I would like to make, but for this first test melt…. I just went to Fred Meyer and picked out some mini-loaf pans and a muffin tray. I had just arrived and was having a look at one, when an older lady came by and espoused her undying love for those mini loaf pans, evidently they are just the right size and she could get 5-6 loafs out of a normal recipe, and especially now that she only had her and her husband left in the house… they were just the right size… I didn’t have the heart to tell her I was not going to use them for the intended purpose, that I was going to pour molten metal in them!
The first pour went well but I had forgot the teflon coating was going to burn off the pans and the bit of fire and smoke made it difficult to see for about five seconds. Once both were poured, I put the crucible back in the foundry, added some bell housing scrap I had cut from a transmission put the lid back on and then some more of that extrusion. It all melted super quickly and was really clean, I did not have to skim dross. I did one more pour. Two ingots and two muffins.
I ended up with almost ~#10.75 of aluminum, 4.881 Kilos, 4 in ingots and 2 in muffins.
I may take the wire wheel to one of these and sand it up, and polish it, just to see how it works up since these were my first ingots!
After letting the core cure for several days I pulled the bucket out, or tried! It took quite a bit of work to remove the form from the core. Next steps I need to pull out the pvc from the drain hole and start the firing process.
This initial curing/firing schedule is unlike normal concrete curing. This initial firing is designed to allow for any water trapped to make its way out of the body of the furnace without cracking or spalling.
We will start by raising the temperature to about 200f and holding it. Then we will increase it by 200 degees per hour until we reach our goal of about 1800. At that point I will shut it down and try to cool it off as slowly as possible. If everything goes well in this initial firing, we should be good to go and can fire it up and start melting down aluminum, copper or brass to make into ingots.
On Monday I worked on getting the core ready to pour, this included drilling a hole for the tuyere in the keg and in the bucket I was using for a form. Once that was done I inserted the pipe and secured it with duct tape. I started mixing the cement and poured it into the form, then used a stick to try to make sure we had no large voids and then used a hand sander to try to vibrate any air bubbles out.
The greensand came in the post. One more thing to add for the foundry project. This is “Petrobond” Casting sand. It is supposed to hold its shape very well after packed, and not need to be mulled. I will need to build a cope and drag setup once I get the foundry closer to completion.
After a week or more of inactivity I got back on the foundry project. I managed to get some of the insulatory refractory cement mixed and put in place as the top and the base of the foundry. Next up will be cutting the holes for the tuyere in the side of the keg and form. Then placing the form in the center and pouring the core.
I have wanted to work with molten metal for quite a while, It is one of the myriad hobbies I have always wished to pursue. I had a taste of it when in High School, we were able to melt aluminum and then machine our pieces in the lathe.
I stumbled down the rabbit hole on youtube a few months ago watching people melt aluminum and other metals in home foundries with propane or waste oil and was mesmerized. It seemed like anyone could make a cheap one and use it, but the more I watched and learned the more I realized most of these were just falling apart after a few melts. I wanted something that would last for many pours. Then I found a set of videos that a fella had put together outlining his build and documenting the steps. I chose to model my foundry after his.
One of the reasons I really liked this design was the the burner. It is able to use propane or waste oil, peanut oil, diesel or just about anything combination of that sort of thing. For aluminum only propane will be needed, for other metals it will be great to have additional BTUs available. Here is the video of his burner followed by some of my pictures of mine so far: