Time for a long overdue update. As I mentioned previously, I felt the need to strip all the paint and derust the column, in order to do that I had to build a hot tank and a drusting tank.
Since these tanks were to live outside behind the shop and i intended to insulate the hot tank, an enclosure needed to be built to house them. I started with building a frame out of some lumber I had laying around.
Then the enclosure was wrapped in a 1/8" plastic sheeting material.
Since the large parts of the mill are too heavy to lift up into the barrels an overhead gantry was needed to afix a chain hoist.
Unfortunately I didn't get any photos of the angle iron and pulley system which allows the chain hoist to slide back and forth. I could provide some close up photos in the finished state if anyone is interested. Otherwise here's the finished contraption in it's new home.
For the hot tank I sourced a 55 gal steel drum with removable lid from someone on Craigslist. Here it is all wrapped up in it's blanket of R-13 that was left over from insulating the shop.
Looking inside the barrel you can see the 5500w hot water heater element, the steel frame that was fabricated to protect the element and provide a platform to set things on while degreasing. Also note the ground stud around 4 o'clock and the k-type thermo couple probe around 6 o'clock. You can also just barely see the drain hole below the element, this leads to a ball valve outside the enclosure, this will be used to drain into 5 gal containers to be disposed of at the local hazardous waste disposal site.
A dedicated 30amp circuit was run back to the waterproof enclosure for the control panel, which consists of a 50A 240v contactor for main disconnect (power on/off), a two position switch for controlling that contactor, a PID controller for temperature control of the hot tank and a solid state relay for pulsing the heating element on/off based on output from the PID controller.
Now for the de-rusting tank. For optimal performance a cage style anode was fabricated out of 1/4" x 2" flat bar stock that was sourced from the estate sale where the mill was found. The round hoops are something like 18 gauge steel that were first run through the slip roller the welded to close the circle. The vertical bars were then bolted into place before welding, just to ease assembly.
The electrolysis de-rusting tank needed to be plastic to prevent corrosion of the tank during the process. Luckily I had this blue barrel laying around, so I cut the top off and put the steel anode cage inside. A bulkhead fitting was installed in the bottom of the tank and ran out of the enclosure for disposal of the used electrolysis solution (washing soda).
I don't have any photos of the lab style power supply hooked up but here's one of the tank bubbling away.