MJP

NS: I have not used flux. I'm using a spoon to stir it a bit to bring up anything stuck to the bottom followed by skimming the top. The ingots look good to me, but I am sure there are impurities. My thought was to get something that could be refined further in a future melt when I am ready to make something. It's not fuel efficient to melt the same metal twice, but this is part of my learning process to break things into smaller steps to see the results of each step. Fluxing and degassing have been left for future investigation. It seems like there are a lot of flux options. I need to find a list of fluxes with uses explained. Perhaps a different flux would be used for recycling a radiator versus a cylinder head. More research is needed. My perception of the flame is unburned gasses are exiting the furnace due to a lack of oxygen. The gasses burn once it exits. Since the furnace is getting plenty hot, I have to conclude that I could use less fuel. There is probably a formula to calculate the ideal pressure based on the size of the orifice and the size of the venturi. Pressure adjustments don't help. Lower pressure makes the flame unstable. Would a smaller orifice at same pressure be worth testing? Or, a bigger orifice at lower pressure? The draw of air would seem to depend on gas velocity, so I would think a smaller orifice at the same pressure would increase fuel to air ratio. I live 1 mile from the IAC, so I will definitely check it out. Funny how a resource so close can be overlooked.

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.

I found and visited a local supplier today who sold me Pacocast 28LI castable for the bottom and gave me a ceramic fiber blanket that is more than enough for the sides. Your advise to include a hole in the bottom with the plinth above makes total sense. And thank you for supplying the correct word "plinth." Now that I have the thing pictured in my mind, I know what I need. What wasn't making sense was building it entirely with ceramic fiber and there weren't any detailed diagrams on the construction of a foundry using ceramic fiber sides showing the bottom. I can bring the torch nozzle in at plinth height, so no direct flame on the crucible. I think you misunderstood. My question was not about how to lift a crucible out of a foundry. My question was on what to use to keep the crucible off the foundry floor to avoid direct flame contact and promote even heating. Your admonitions are appreciated and certainly not ignored. Consider that one could know how to safely operate a foundry, but not know how to construct same. Similarly, many people can safely operate an automobile, but few know how to build one.

New guy here. Wanting to build a foundry using a 33 gallon drum. Prefer using a combo of kaowool, rigidizer, and ITC100. Seems like the most fuel and time efficient setup. After reading numerous websites of guys building foundries, I cannot find anyone addressing the method used to raise the crucible off the floor or what they use for a floor on a foundry with kaowool lining. I've read that you need the crucible off the floor for even heating. I've read that the crucible should not be directly in the flame. If both of those is true, something must be used to raise the crucible off the floor. The other issue is that a kaowool floor doesn't seem sturdy enough to me to support the weight of the crucible and content. I've seen guys cast a table to rest the crucible, but I would think that this would compress the kaowool leading ineffective insulation. So what's the best solution? Do you cast a solid bottom and use the kaowool only for the sides? Can insulating bricks be used on top of the kaowool bottom with a cast stand to raise the crucible? Buying the fewest materials is preferable to save money and I don't want to start buying stuff until I have a pretty good idea of what I need. Thanks for any help.