Denny my understanding is that the black residue is
magnetite.Which can for the most part be scrubbed off with a little work or the part can be dipped in some type of phosphoric acid used to clean metal, to remove it. Either way I havent noticed any problems with painting right over it.
An issue to consider is heating the part after tanking as steel is fairly porous and will wick up water. I use my propane torch slowly so as not to warp anything, but I imagine a little bit of time in a warm oven would do the trick as well. Also expect a small amount of flash rust once the part is completly dried. But the small amount is usually so small it can be ignored, or as said, use the phosphoric acid dip.
Im a bit of an obsessive-compulsive person, and when it comes to working on my vehicles and can understand your apprehension when working on something new due to the mixed reviews. My opinion is if there is a bad review someone didnt do it right.
If it wasnt an ideal process do you think Scientists and archaeologists would use it to preserve artifacts?
The nice part is it is an almost instantaneous process and you can see it working immediately, as the hydrogen bubbles come of the part being cleaned. I was real skeptical at first, but Im already considering getting a large farm tank at some point to do whole doors and fenders and using a small welder for the power supply.
Im trying my hardest to pressure you into trying it, is it working yet?
Once you decide please let us know how it goes! Good luck, Jeff
