HomeFAQsSuggested
Books
FORUM
current topics
SEARCH  🔍
THIS SITE
finishing.com -- The Home Page of the Finishing Industry
Not a lecture hall but a roundtable with a seat for you!
60,000 topics spanning 36 years. Education, Aloha, & Fun


topic 50266

Phosphatizing Q&A, Problems & Solutions

Current question and answers:

January 11, 2021

Q. We are school furniture company we do interior welded furniture from steel tubes and sheet metal we are using a cleaning hand process and we want to get a superior quality so we landed on using shot blasting and 3-steps process but we wondering ...
1- Is it enough for good quality?
2- What's better to use dipping or spraying in terms of quality-cost-processing time-efficiency?
Best regards

Ahmed Eid
- Cairo Egypt


January 2021

A. Hi Ahmed.
1. Shot blasting and 3-step phosphatizing sounds excellent for stuff not exposed to the elements. 2. Dipping and spraying are both widely practiced but, all things being equal, spraying offers the advantage of mechanical scrubbing action and continuous exposure of the surfaces to fresh solution. If you can easily hang and handle all the parts for spraying that's probably the way to go.

Luck & Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
finishing.com - Pine Beach, New Jersey
Aloha -- an idea worth spreading




Previous closely related Q&A's starting in:

2001

Q. We have Powder coating plants. Also we use metal pretreating line for this (rust removing). But the current method is not very efficient for us, because it is dipping method. Therefore we want to know about spray method.

INDIKA P [last name deleted for privacy by Editor]
TRADING - SRI LANKA


A. Hi, Indika. Yes, spray systems are usually considered more efficient because the mechanical energy of the spraying makes for faster processing and sometimes better consistency.

There are a number of manufacturers of such phosphatizing systems, and these days you can get all-plastic construction if you wish. They essentially consist of nozzles for spraying the solution, inside of tunnels which collect the overspray and direct it back to the reservoir for pumping through the nozzles once again.

Good books about phosphating are Samuel Spring's "Preparation of Metal for Painting" [affil. link to book on Amazon and "Phosphating of Metals" [affil. link to book on Amazon, ... on AbeBooks -->] by Werner Rausch. Good luck!

Regards,

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



White spots after spray phosphatizing (10 Stage Zinc phosphate)

October 11, 2008

Q. We are getting white spots after phosphating, Zn phosphate 10 stage in spray.

Please help me.

Regards,

Ashu

Ashutosh Pandey
Employee - India


October 2008

A. Hi, Ashutosh. We've posted your inquiry, but I think it may prove a bit vague for the readers to help you as much as they'd like to. A picture would help identify the defect you are trying to describe. Secondly, have you been successfully phosphatizing for years and this problem just came up yesterday, or is the phosphatizing line just being started up and has not yet produced a satisfactory part? Is there a particular type of surface, or a particular orientation in the spray booth associated with the spots? Do the spots show up early in the process, immediately upon the completion of the process, or a month later? Get back to us please. Thanks!

Regards,

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


October 16, 2008

A. If the chloride content in your phosphate bath is too high it is possible to get a condition known as white nubbing. This is most prevalent after a cleaning with HCl if not enough rinsing was done after. A fluoride additive is usually added to displace the chloride to rectify the problem.

Ron Zeeman
Coil Coating - Brampton, Ontario, Canada



Wire phosphating gets white powder layer

May 15, 2017

Q. In the last 20 days, after phosphating of wire, a white powder layer deposits over top of wire . This layer after the soap dip, turns yellow.
This yellowish deposit sticks on the surface when drawing.

We have 5 acid dips (16-18% conc., and total dip time is 30 min);
After acid, we have jet spray followed with 3 water rinses;
After Phosphate, we have 2 water rinses and a neutralizer.

Nagasubramanian Srinivasan
- TamilNadu, India


May 2017

A. Hi Nagasubramanian,

Although anything is possible, I doubt that the acid dip or rinsing is the issue. I think your phosphatizing process may have gotten a bit out of control. What can you tell us about that?

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
finishing.com - Pine Beach, New Jersey
Aloha -- an idea worth spreading


May 17, 2017

A. Hi Nagasubramanian,

White deposits in phosphate are usually caused by phosphate sludge in the tank.

How often do you filter or remove sludge from the phosphate tank?

Regards,

Daniel Montanes
TEL - N FERRARIS - Canuelas, Buenos Aires, Argentina



Spray vs. dip phosphatizing

Ed. note: No
abstract questions
Please!!

December 15, 2020

Q. What is the effect of Spray pressure in Spray Phosphating Process?

Vikas Ujjawal
- Delhi/New Delhi


December 2020

A. Hi Vikas. The general idea is that the mechanical scrubbing action and constant exposure of the metal surface to fresh solution results in faster and more even phosphatization.

Luck & Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
finishing.com - Pine Beach, New Jersey
Aloha -- an idea worth spreading

none
adv.
this text gets replaced with bannerText
spacer gets replaced with bannerImages

Q, A, or Comment on THIS thread SEARCH for Threads about ... My Topic Not Found: Start NEW Thread

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 need a product/service, please check these Directories:

Jobshops Capital Equip. & Install'n Chemicals & Consumables Consult'g, Train'g, Software Environmental Compliance


©1995-2021 finishing.com, Inc., Pine Beach, NJ   -   About finishing.com   -  Privacy Policy
How Google uses data when you visit this site.