How to soak clean and electroclean
A discussion started in 2003 but continuing through 20182003
Q. I have a galvanising plant in which we coat zinc on iron wire or mild steel. The first process in our plant is acid pickling. I just came to know that before acid pickling soak cleaning and electrocleaning should also be done. I want to introduce these two steps in my plating process before acid pickling. But I don't know the process. Please explain to me the entire process of soak cleaning and electrocleaning.
wire - New Delhi, India
A. Yes, Ayush, alkaline cleaning processes should precede acid activation. A soak clean or an electroclean, or both in sequence, may be used to remove oils and soils. They are usually hot (about 180 °F), very highly alkaline and with detergents. Proven proprietary products are almost universally used, and certainly best, especially for the inexperienced because good cleaners should saponify, wet & emulsify, deflocculate, chelate or sequester, buffer, and inhibit.
The main difference between soak clean and electroclean is that in the latter the work is electrified at a current density of between about 50 and 100 ASF, to generate hydrogen or oxygen bubbles at the work surface which greatly assists in the cleaning.
Ted Mooney, P.E.
Pine Beach, New Jersey
Electrolytic degreasingOctober 17, 2018 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread
Q. I would like to know the best detergent I should use to do an "electrolytic degreasing" of my samples (It could be brass, steel or aluminium)?
I had in mind to use my samples as cathodes in the process (does the detergent needs to be acidic then?)
A. Hi Zakaria. We appended your inquiry to one of a dozen or so threads we have on the subject. If you could put this into fuller context, we can probably answer more exactly. But generally, it requires more than a detergent to do electrolytic degreasing (the detergent is probably not a good conductor, for one thing). Further, you usually can't use the same electrolytic cleaner for brass, steel, and aluminum.
I'm not quite sure what you mean by "use my samples as cathodes in the process" or what your process is. But you generally need to acid activate metal after you have alkaline cleaned it. Good luck.
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Striving to live "Aloha"
October 22, 2018
A. Hi Zakaria!
We use anodic cleaning (parts as anodes) so hydrogen forms only in cathodes, avoiding hydrogen embrittlement.
In general, electrolytic anodic degreasers are alkaline, and cathodic are acidic. Cathodic is used on non-ferrous parts and only anodic in high strength steels because of HE.
So, as Ted said, I don't think you can use the same degreasing agent for all three materials.
Best of luck picking the best product for you!
TEL - N FERRARIS - Canuelas, Buenos Aires, Argentina
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