EdInNH

Any welding shop that does sanitary stainless welding should be able to passivate the stainless for you. There are some do-it yourself techniques worth trying. I recommend you passivate the stainless after any grinding or heavy buffing. The rust resistance of stainless steel is dependent on the layer of chromium oxide on the surface. Usually it will form naturally but sometimes it doesn't. By passivating you help the chromium oxide layer form. As has already been mentioned avoid embedding plain steel in the stainless steel. A plain steel wire brush or steel wool will leave microscopic pieces of steel embedded in the surface of the stainless steel. These will create gaps in the chromium oxide layer and rust will form. Do not use a stainless steel brush if the brush has EVER been used on plain steel. The brush will have steel particles embedded in the bristles which can transfer to the stainless surface. The same warning applies to the non metallic abrasives like the Scotch Brite (3M) pads, never use a pad on stainless steel if it has ever been used on plain steel. The simplest and safest passivation is a strong citric acid bath. Almost as safe and much better removing rust is hot phosphoric acid (the commercial rust remover Navel Jelly is 10 to 30 percent phosphoric acid and a touch of sulfuric acid in a water based gel). Hot sodium hydroxide solution is next. The downright dangerous options are Hot concentrated Nitric acid and Hydrofluoric acid. The Hot Nitric Acid is pleasant compared to the Hydrofluoric acid (HF). A small amount of hot concentrated Nitric Acid spilled on skin will lead to a bad burn. A small amount of HF spilled on skin can be fatal. A friend is a chemist at a pharmaceutical company. The production and maintenance staff will use Hot Sodium Hydroxide solution in the production system for passivation but if that doesn't work the part of the plant is evacuated and a special team comes in to use hot concentrated nitric acid. I would at least try soaking in food grade phosphoric acid (or even Navel Jelly) The Rust Store (http://www.theruststore.com/CitriSurf-Copper-Sulfate-Passivation-Test-Kit-P220.aspx) sells a kit to test passivation. They also have a one step rust removal and citric acid based passivation gel (http://www.theruststore.com/CitriSurf-2310-Spray-Gel-P330.aspx). I plan to use this product the next time I need to clean and passivate stainless.

Does the corn have the same water content (bushel weight) ?

Consider adding a second 5500W heating element wired directly to a 240 volt power cord. For a $30 element and the cost of welding a second heater flange to the tank you will cut heat up time in half. (Start a run with both elements at 5500W and shut off this full power element as the wort approaches distilling temperature and adjust the distilling temperature with the variable control.) The heat controller pictured on you web site uses a short heating element (High energy density). This element will be more likely to scorch your wort (and the suspended solids) than a system using a longer element (low energy density). (e.g. the Camco 02962/02963 5500W Heater Element available on Amazon.com) How often do you plan to run the still? I would expect to run at least 5 to 10 still runs a week. You have only one fermenter to feed the still so you will be limited to one or possibly 2 runs a week. For a minimal equipment package skip the stainless conical fermenter and ferment in plastic barrels. You could use 30 or 55 gallon open head drums or food grade trash cans (e.g. Rubbermaid Brute). With 10 drums you can feed the still. If you want the stainless bling consider a larger fermenter which will hold 3 or more still charges. Look for the 55 gallon drums locally. Almost every city will have a drum recycler who can sell you once used food grade barrels for a small fraction of the price you quoted. (I recently purchased some 20 gallon barrels, used to ship salt, for $15 each. I would expect to find 55 gallon drums for between $10 and $55 each) Direct heat for mashing will be labor intensive. You will need to stir continuously to avoid burning the mash at the bottom. Consider steam injection mashing. You can use your still pot and connect pipes to the bottom of the mash vessel to inject LOW PRESSURE steam into the mash. (Of course this needs a 5 or 10 psi pressure relief valve to prevent excess pressure!) If you will ferment on the grain you can mash in the fermentation vessel. A Google search for steam injection mashing will give many references. Edited because I can't spell.