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Turkey Fryer FoundryThe "turkey fryer" foundry uses 2300 deg. Kaowool for insulation, it is not cast refractory. That stuff is too dang heavy. It is a standard off the shelf Brinkman 30 qt. turkey fryer including the stock cast iron burner with a stamped diffuser. (I bet somewhere a product liability lawyer just messed up his pants when he read this!) I started casting with just the stock fryer base and none of the add-on insulation. It took a full hour to melt a crucible of zinc running wide open and squeezing the propane tank to get all she would do. The first test I did was to put some Kaowool in the hole around the burner, the theory being that all the cold air in the room was being sucked in around the burner with the hot air and was cooling the crucible. I didn't know if the air was needed for combustion, so I just put the Kaowool in it to see. Well, the flame was still nice and blue and it cut my melt times dramatically. So then I just started adding Kaowool on the inside of the burner until the burner was basically imbedded in it. The furnace got even better. So then I decided to see what would happen if I rolled up a roll of Kaowool for insulation on the outside, rolled up three layers of 1" thickness around a piece of 8" pvc pipe for a form and wired it together and tried it. Man, things really got to cooking! So then I started looking for something to protect the Kaowool so it wouldn't get all beat up from the handling. After looking all around my shop and scrap pile I had just about given up when I saw the pot for the turkey fryer! I tried it and it fit perfectly! So I cut the bottom out of the turkey fryer pot and screwed in some stainless screws to hold the Kaowool in place, then turned the lid upside down, took off the handle and cut a hole in it and stitched three layers of 1" Kaowool to the bottom with .023 stainless Mig wire. I added some pieces of aluminum flashing to protect the outsides of the exposed Kaowool and it was done! One of my casting mentors (Ed Gladkowski) pointed out that I should read the MSDS of the Kaowool, and when I did I realized the fibers were a hazard. I coated the insides of the Kaowool with ITC100 and now I have a fairly stable crust that seems to work well for reflecting heat plus it traps the fibers of the Kaowool to minimize the amount of that I put in the air where I am working. Anyone that uses Kaowool should seriously consider the ITC100 product to cut down on the fiber emissions. A further advantage of the ITC100 is that it makes the insulation look like one piece and really cleans up its appearance. I have used the turkey fryer foundry for maybe 6 months now. I have cast about 250# of zinc, then turned over 150# of it into homemade ZA12. In addition I have melted close to 100# of aluminum, so I am sure it will work well for anything in those ranges. I usually cast 20# batches of zinc but could cast almost twice that much in a melt if needed. The crucible holds right at 13# of aluminum. I don't think it would be all that good for bronze, a better burner would be in order for that. I would also recommend beefing up the steel that the crucible sits on if higher temps are planned. Silicon carbide crucibles do not fit in it without some modifications to the steel pot supports.
This could be cut almost in half by not getting the new regulator and by sharing the roll of Kaowool with other users. And if you already have a turkey fryer or can find one at a garage sale, you can really get going cheaply. I bet Ron Thompson's King Kooker would really get the job done with this stuff, that has a much better burner than what I am using. The original regulator was a high pressure one and could be adjusted, I just couldn't tell what pressure I was running. When I went shopping for a gage I found the regulator with the gage, it was almost closing time in the little town I live in and I wanted to make a melt so I forked over the cash and went home and melted metal. I run the new regulator somewhere between 14 and 16 psi. The only time I have had a problem was at the casting session where the pictures were taken for the other folder about the turkey fryer furnace (pictures posted by my other casting mentor, Larry Will). Naturally it would act up when there were witnesses! The thing started whooping, about once every four or five seconds. I guess it just didn't like the big city air or something. I cut the pressure a little and let it warm up, then it was OK. I don't think the insulation restricts the flow of hot gases. When I am running at night I see maybe 8" to a foot of flame coming out the top, but from what I have seen I think that may be normal. I have a 1 1/2" annulus around the crucible. It is a little smaller than I have seen claimed is necessary, but with the type of burner I run the burn is actually right at the burner. When I am making the ZA12 I have the lid off most of the time poking the aluminum cans under the zinc and really can't tell much of a difference with and without the lid so I think the exit hole is sized about right. I think this is a fairly decent furnace to play around with for the lower temp metals. It is light, I carry the whole thing crucible and all to my storage shed. That plus maybe those nosy neighbors will think you are cooking a turkey or something and leave you alone! Ray Ethridge |
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