Thanks guys. I appreciate the info. I live in Indianapolis. I found a local supply house since my last post. They provided the castable refractory, a free remnant of ceramic fiber, and some setup advice. The ceramic fiber remnant was 1" x 24" x 10'. Hardly a remnant to me, but it was to them. I bought some rigidizer online along with ITC100 directly from ITC. Buying direct from ITC was cheaper than the usual online options.
My foundry consists of two cut down steel drums with a 14" diameter. I thought it was 33 gallons, but it was more like 20-25 gallons. One drum was used for the body and the other for the top. The reason I used two drums was so that the I could use the stronger top and bottom rings at the opening and avoid any raw edges. The floor is 3" of castable with the suggested hole in the middle. I also cast a plinth using a 4" PVC union as a mold and included a path for molten metal to find the hole in the floor. The walls and lid are a double layer of the 1" rigidized ceramic fiber. Both fiber and castable are top-coated with ITC-100. The lid is hinged with an angled 3' handle to allow opening without getting too close. Heat is provided by homemade propane torch similar to the examples found online with my own personal touch. The heat chamber is approximately 12" tall x 9 1/2" diameter. The foundry is mounted on a welded angle iron frame and raised high enough to place a steel bucket underneath to contain spills.
The one tip I would pass along to anyone using ceramic fiber on the walls is to cut it at an angle rather than a square cut so that the two edges of your vertical seam overlap. Having the edges overlap prevents any potential air gaps along with a more stable base for coatings that will reduce the risk of cracks at the seam.
I have fired it up and melted about 50# of aluminum so far. The good news is that it will start melting within 15 minutes from startup! I have not attempted to cast anything other than ingots while I learn. One of my melts included a radiator and ac condenser, which made for an interesting experience. It turns out that the dross included magnesium and my foundry was hot enough to catch the magnesium on fire. It didn't appear to be burning when I spooned it off the top of the crucible. However, after sitting in a steel pan for a couple of minutes I started to notice a bright light developing. It got as bright as a mig welder. I used a steel spoon to try to smother it in the aluminum oxide. Unfortunately, I only had half a spoon when I pulled it out. It was hot enough to melt the spoon. I brought it under control with some sand.
Another tip for pouring ingots: My first pour was into a brand new dollar store steel bread pan. The aluminum stuck to the pan! I spent 30 minutes with pliers ripping the steel off the ingot. Before my next attempt, I used a propane torch to burn off whatever coating was on the pan. I then carbon coated the pan with my acetylene torch sans oxygen. The ingot slid right out on the next pour. Not sure if one or both steps were necessary, but that is what worked for me.
Pictures will be posted once I am satisfied it is done and safe.
Some questions did arise during my test runs:
1. There is about a 12"-18" flame coming out the top of the foundry when the torch seems to be at its peak. Is this normal?
2. The torch will flame out if I go to maximum immediately after lighting. In order to get to maximum, I have to do it slowly and not close the lid too soon. It seems that the heat inside the chamber helps the torch function better. Could this along with Q1 be a sign that the flame is oxygen starved?
3. I already accumulated about 5-8# of dross, which contains a significant amount of aluminum. I'd like to reclaim it, if possible. Is a mixture of NaCl & KCl the best way to separate the aluminum from the dross? Is there a rule of thumb on how much to use and when to add it? I am using a steel crucible for aluminum melting, if that matters.