No passwords, no registration, no paywalls, no popups, no AI

As an Amazon Associate & eBay Partner we earn from affil links

Home /
T.O.C.
Fun
FAQs
Good
Books
Ref.
Libr.
SITE
NEWS
Help
Wanted
Current
Q&A's
Site 🔍
Search
finishing.com -- The Home Page of the Finishing Industry Search our quarter-million Q&As

Home of the finishing HOTLINE since 1989

-----

HCD Area Problem!





2007

Hello All!

I m running a Rack plating tank of capacity 800 ltrs. of Acid Zinc.I m maintaining Metal as 35 gm/ltr. (30--35 gm/ltr.);Chloride as 130 gm/ltr.(120-140 gm/ltr) & Boric as 33 gm/ltr.(30--35 gm/ltr.)
My problem is that I m facing the problem of HCD area i.e when I did Hull-Cell at 1 Amp. for 5 Mins. I have no Problem ,but when I did at 1 Amp. and for 10 Mins. a dark brown colored start appearing at HCD and after HNo3 dip I found dark Silver grey color in only HCD area whereas my LCD area and Medium area is cleared and shiny.So, what is that dark brown color.
Is it due to some Metalonic Impurities or what?
I have packed zinc dust on eBay or Amazon [affil link] ,Carbon at 100gm. twice
I have packed packed KmNo4 at 100gm.twice in order that no iron or any other impurity should be there.
I did Hull Cell ⇦ huh? at 1 Amp. at 10 mins. with only 'M' as there may be un-balanced M-R ratio, so what I find that in Hull-Cell of 250 ml. I put total 18.5 ml after various trial.So corresponding to 800 ltrs. it comes out to be 60 Ltrs. So should I go for it or not. please Tell.

Sean Aarchr
Engineer Q.A - Chandigarh



The Indian brighteners are not formulated to work at that metal concentration.

Reduce metal to 20 - 22 gms and Boric likewise. Reduce the chlorides to a 1 : 5 ratio to the metal and start work.

Khozem Vahaanwala
Khozem Vahaanwala
Saify Ind
supporting advertiser
Bengaluru, Karnataka, India
saify logo
2007



Dear Khozem Vahaanwala

I have also did the same thing for atleast 1 week. But in vail.

Sean Aarchr
- Chandigarh
2007


Sorry! Finishing.com is temporarily Read-Only.
Ted Mooney is retiring but I have several offers to take it over.
We're working hard to make sure we find it the best new home.





Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

Finishing
Jobshops
Capital
Equipment
Chemicals &
Consumables
Consult'g,
& Software


About/Contact  -  Privacy Policy  -  ©1995-2026 finishing.com, Pine Beach, New Jersey, USA  -  about "affil links"