G'day MF,
Ok guys, now that I have the witches brew sorted, how long, four weeks? Can I pour the rubbish onto my lawn without murdering it?
Taking those in order, it's a bit of a 'how long is a piece of string' situation.
Depends firstly on how heavy the rust buildup is - and I strongly recommend removing all of the 'loose' rust mechanically, using a wire 'cup brush' on a 100mm angle grinder, before it goes into the molasses bath. [Do use appropriate PPE here - my getup is full face shield, long leather welders gloves, and a leather apron for this job - after having to pull a few busted off wire bristles out of myself...]
Secondly, this also depends on the ambient temperature - speedy will get much quicker results up in Bundaberg than us Mexicans will, at this time of year.
That said, you will have to pull the workpiece out of the solution regularly, hose/brush [an old dishwashing brush is what I use] it off on the lawn, and see how the job is progressing.
Weekly at a minimum, with sheetmetal parts - I forgot about a sheetmetal top from a Primus kero stove once, and made 'lacework' out of it... Fortunately, I had a NOS one in reserve.
Disposal - it's fine to pour the used solution down the municipal sewer system - there are no 'nasties' in it; that's one of the major advantages of this method.
A couple of caveats:
1. The bath needs to be covered up in operation; or insects, rodents etc will drown in it
2. Do
not set it up in any enclosed building - it gets pretty stinky anyway
