What is a Hull Cell Test, Why is it done, Where to Get a Hull Cell

A. Hello again, John. Thank you for the kind words.
I don't know of any current presentations on Hull Cells for cadmium plating, but if we go back 50 years, here's a page from AES "Hull Cell Tests for Quality Plating" covering the effect of too little and too much brightener. There were color slides corresponding to the printed B&W photos but I misplaced them, probably 49-1/2 years ago :-)

Google finds an almost endless list of Hull Cell presentations and videos, so I can't view them all to suggest the best, but I think both of the following are quite good:
• "Interpretation of Hull Cells, How & Why" and
• "Interpreting Zinc Plated Hull Cell Panels"

The zinc plating is similar enough that I think the above video will be quite helpful. Basically you will probably see burnt plating at the very left edge, and little to no plating at the very right end, but you should ideally see good plating all across the current density range except for the true extremes if the brightener level is right.

If you send a pic of your Hull Cell panel for posting here, hopefully a reader will be able to make suggestions. If it doesn't photograph well because of the shininess, the professional approach is to reflect some screening in it; if that's not available, perhaps reflecting a page from a book might suffice although I haven't tried it :-)

Since you are new to Hull Cells, remember that testing for good plating all across the current density range is one of its uses, but the other use is for "scaling up" tests & calculations whereby you don't make chemical adjustments to your 27 gallons until you try them on 267 ml first. Thanks again for the feedback. Luck & Regards,


Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Hi.
I am neither a proficient Hull Cell user, nor a chemical technician, so I hope other readers will chime in, but the lack of brightness of the deposit in the low current density (if that's what I'm seeing) seems to indicate shortage of brightener rather than excess.

Maybe add one drop of brightener to the Hull Cell and stir before trying your next panel and see if the panel gets better or worse. Luck & Regards,


Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Is your cad process matte or bright? I typically run both a pure cad with no brightener and one with a small amount of brightener. The hull cell on the matte process should have a satin look across the panel with no burning or discoloration. The bright will have a broad range across the panel with only minor discoloration in the extreme high current area. Organics will cause some swirling and you can carbon treat for it. then add back brightener. I start with a liter and treat it in the lab first. Also a good idea is to have a sample tested on an A.A. for trace metals since only a few ppm of chromium will affect it.(from the chromate process)

A. Hi Sue. I don't think either of these is readily available. Marilyn was the author of the illustrated slide lecture offered by AESF entitled "The Use of the Hull Cell", and it is possible that an AESF/NASF branch has a copy (I had a copy a long time ago). Google.books.com told me that the 2nd was published by Hanson-VanWinkle-Munning in 1997, which led to worldcat.org saying a copy was available at Wayne State University library in Detroit, which led to learning that they apparently they still have it, ref.:
elibrary.wayne.edu/record=b2152282~S47

Luck & Regards,

A. Marilyn K. Sanicky worked for McGean Rohco and did a series of articles on the Hull Cell. I think they were carried in Metal Finishing or that other publication. Perhaps they can sell you copies of the series. It was very good! She has retired from McGean (which may have since merged into something else).

A. "The Hull Cell" must have been a very popular title. There is a book of this title by Walter Nohse, published by Robert Draper of Teddington UK in 1966, It was translated from the original text (presumably German) by staff of "Electroplating and Metal Finishing" .

I cannot vouch for the cover, as I haven't seen one with a fly cover intact.

----
Ed. note: See Sjamp Van Esch's reply below for the original German version.

A. Hi Michae. I doubt that you'll find such a website because the Hull Cell is such a versatile tool and is used for so many different plating solutions, and in such different ways for them -- but a good on-line link is offered by Reza Esmaelli just below. And you could buy the "Hull Cell CD" from www.nasf.org. Tell us what metal you are plating please. Good luck.

A. THE STANDARD HULL CELL PANEL IS 75MM X 100 MM LONG BUT MANY OTHERS SIZES ALSO EXIST.
70 X 100, 70 X 200, 37 X 150 TO NAME A FEW

A. In the book "Modern Electroplating" , author: Green,
you will find a good description of the principles of the two types of current distribution:

Primary and secondary. The primary is theoretical, based on the geometry of the cell with electrodes. The secondary is experimental, including the effects of the overvoltages at both electrodes. These overvoltages make the distribution more equal over the electrodes.
A third affect occurs when the current efficiencies depend on the current density.
These three effects together result in the effective product distribution over the surfaces.

Ed. note Oct. 2020: We find no reference to a version of "Modern Electroplating" authored by "Green". This may be a typo or mindslip?

A. Tom, I thought there is a German standard for the tolerances; I will look that up. In either case the Book of Walter Nohse about the Hull Cell method doesn't give any tolerance.

Bye,
Harry

A. Hull cells are supplied by Ecograph AG Switzerland

A. I HAVE BEEN BUYING ALL HULL CELL EQUIPMENT FOR THE LAST 6 YEARS FROM PLATING TEST CELL OUT OF OHIO.