Acid vat

[Frank S]

Removing mill scale and surface rust from steel is a laboriously labor consuming process.
you can grind it sand it, wire brush it and sometimes need to do all of the above, or you can sand blast it but there is the labor and time element again. But a product I use often called rust blast has the highest concentration of phosphoric acid allowed by law it literally eats rust and given time will soften mill scale to the point it can be wiped and rinsed away.
But the process takes time as does everything else since you have to keep the metal wet with the acid for a period of time.
A better way to clean rust from small parts like nuts and bolts is to immerse them, then leave them over night or longer.
I have a some long formed and fabricated parts I want to clean. If I can dunk and forget them for a day or so while doing other things, I am removing much of the labor part hopefully. the acid will not react with steel but will cause galvanneal to boil off all of the coating will etch aluminum and eventually erode it away.
here is the vat I made for this process I will know next week after the 55-gallon drum of the acid arrives how well it will work if for nothing else I still have a nice dipping tank.
Made from a full 4x8ft sheet of 14ga Much deeper than I need but better to be too deep than not deep enough.

trough formed in for draining.

source of sq tubing for legs and rim the round part I straightened out to a larger radius to make trusses for my green house.

finished vat just needs painting but that will wait.

The brass valve may be a problem might have to replace with one made of stainless