I'm doing a conceptual design for homemade conical. My plan is to take an old pony keg (the taller/skinnier style) and fashion a stainless steel cone and TIG weld it to the bottom of the keg. Kind of like what yuri did, just with a smaller keg. This should give me ~8 gallons of fermenting space, depending on the cone.
My question is what is the slant height needed for proper yeast drop of a conical? This obviously would determine my perpendicular height. I figure I can plug the numbers in, run it through a 3 piece roller and butt weld the seam. From there I could tack on a dump valve and a drain valve.
As stated this is a concept idea. I got the keg, and a source for some stainless, and means of obtaining the tools. So I might run with it if I can get all the details hammered out.