Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ

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Difference between E-Coat and Cataphoresis Process

2000

Q. What is black electrophoresis/cataphoresis?

I am investigating this process to apply to our steel and Al-alloy racing bicycles.

I know:

that it is a hard, durable, paintable, corrosion resistant black coating,
it seems commonly used in Europe as a coating for bicycle frames, motorcycle silencers, safety boxes, industrial doors (among others),
of it being applied on both steel and aluminum materials (among others).

Does anyone know:

what the chemical composition is,
if it has a different name in North America,
of any sources for it in North America?

Dave Anthony
- Toronto, ON, Canada

2000

"Electrocoating: a Guidebook for Finishers"
by Electrocoat Association

on AbeBooks

or eBay
or

Amazon

(affil links)

A. It is called e-coat and is very popular in the USA, Europe, Asia etc. Try the web site of the Electrocoat Association, you will find there a lot of information.

Sara Michaeli
Tel-Aviv-Yafo, Israel

Multiple threads merged: please forgive chronology errors :-)

Cataphoretic Painting

Q. I am associated with a manufacturer of steel wire. A customer has asked us about KTL, or cataphoretic painting. Can you tell us anything about this process - is it available in the U.S.?

Thank You

John Cary
- Newnan, Georgia, USA
2000

A. Cataphoretic paint is a known process. There are a lot of users and manufacturers in USA for e-coat. Try to contact the e-coat association.

Sara Michaeli
Tel-Aviv-Yafo, Israel
2000

RFQ: DEAR SIR/MADAM,

WE ARE A SUPPLIER OF STEEL AUTO PARTS IN ISTANBUL. WE ARE LOOKING FOR THE MACHINERY AND THE SYSTEM FOR CATAPHORESIS/E-COATING TO ADD TO OUR PLANT. PLEASE ADVISE US ABOUT THE COMPANIES WORKING IN THIS FIELD. WE ARE OPEN TO ANY IDEAS ABOUT THE SUBJECT.

THANKS FOR YOUR TIME AND EFFORT.

SERKAN KOC
- Istanbul, Turkey
2001

Ed. note: Sorry, this RFQ is old & outdated, so contact info is no longer available. However, if you feel that something technical should be said in reply, please post it; no public commercial suggestions please ( huh? why?)

RFQ: WE WANT TO SET UP A FACTORY IN BURSA.WE ARE LOOKING FOR THE MACHINERY AND COMPLETE SYSTEM FOR CATAPHORESIS/E-COATING. HOW MUCH DOES IT COST APPROXIMATELY INVESTMENT. PLEASE ADVISE US ABOUT THE COMPANIES WORKING IN THIS FIELD. WE ARE OPEN TO ANY IDEAS ABOUT THE SUBJECT AND PARTNERSHIP.

THANKS...

ALPARSLAN ORUC
- BURSA, TURKEY
2002

Q. Dear Sir,

Our company is one of the pioneer organizations in India for painting systems. I would like to know whether after Catophoretic treatment Liquid Finish Painting can be done OR whether only powder coating can be applied ?

Thanks,

Suresh Kumar
. - Pune, India
2002

A. Cataphoretic coating is an excellent primer coating and as a pioneer company in painting this should be known to you. It is most widely used for primer coating on all automobiles which then go in for liquid spray painting.

Gurvin Singh
Mohali, Punjab, India
2002

RFQ: We are a Brasilian company that produces surface finishing equipment, and we want to increase our product lines with this lacquers, in order to satisfy our customers.
Thanks,

Martin Udo Becker
plating equipment manufacturer - Canoas, Rio Grande do Sul, Brasil
2005

RFQ: We are a Italian Company, our production is automating systems for door opening. We want to transfer a part of our productions on China, for this reason I want to contact a China supplier for cataphoresis process to be applied on metallic steel parts. You help me to have information about this. Thanks in advance.

Best regards.

Marco Casari
- Bologna, Italy
2005

Q. Is there any difference between e-coating and cataphoretic coating?

Krishna Subramanya
- Melrose Park, Illinois, USA
2006

Q. We are in requirement of Black Cataphoresis process to be performed on our product that are Auto Parts. I wanted to know what is basic difference between Cataphoresis and E - coating.

Mina Mohnani
Manufacturer of Auto parts - Rajkot, Gujarat, India
June 11, 2008

June 2008

"Handbook of Electropainting Technology"
by W. Machu

on AbeBooks

or Amazon

(affil links)

A. Hi, Mina. No difference really; it's just semantics. E-coat is shorthand for electrophoretic coating. Cataphoretic coating is an electrophroretic coating process when the part being coated is cathodic; anophoretic coating is an electrophoretic coating process where the part being coated is anodic.

Regards,

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

RFQ: Dear Sir,

We are large supplier for Tata Motors , John Deere & JCB, Approved in powder coating. Now we require E-Coating system process in our factory. Please give us your best suggestion.

Thanks & Regards ,

Sandeep Shinde
Plant Head - Pune, Maharashtra, India
February 20, 2011

Multiple threads merged: please forgive chronology errors :-)

Cataphoretic Paint vs. Electrophoretic Paint

Q. We require Zn-Fe plating of 8 Microns followed by cataphoretic paint of 10- 15 Microns.
Please explain the difference between Zn-Fe Plating, Zn Coating, Alkaline Zn, Acidic Zn.

Also please explain the difference between electrophoretic painting, cataphoretic painting and anophoretic coating.

Ankur Aggarwal
Buyer - Ludhiana, Punjab India
February 13, 2013

A. Hi Ankur. That's a tall order, but here's a brief intro --

Zinc can be applied to steel parts to offer them cathodic protection (i.e., the zinc will protect the steel by sacrificing itself). Zinc coatings can be applied many different ways: hot dip galvanizing, electroplating, mechanical plating, dip-spin coating, sherardizing, flame spraying, etc. Of these different ways, electroplating is usually the most economical and satisfactory when coatings are in the 8 micron range. The zinc electroplating bath can be acid based or alkaline based.

Zn-Fe is an alloy plating. It is believed that carefully engineered zinc alloy platings like Zn-Fe, Zn-Co, Zn-Ni, and Sn-Zn outperform plain zinc plating.

Electrophoretic paint (also called electrophoretic lacquering, e-coating, electrocoating, electropainting) is a process for applying organic coatings (paint) in a matter rather analogous to electroplating. The work piece can be either cathodic (in which case the coating may be called cataphoretic, cathodic electrodeposition, or CED) or anodic (in which case the process may be called anaphoretic). I am not an expert in the following assertion, but it is my understanding that early electrodeposition was often done with anaphoretic paint, but cataphoretic is perceived today as generally superior and is far more common these days.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
February 13, 2013

Information about cataphoresis

October 2, 2017

Q. Hello everybody,

I'm doing a bit of research about e-coating processes and I still don't understand why all the suppliers I can find only provide black or white cataphoresis.
I got that cataphoresis is about suspended organic paint particles which will be electrically deposited on the cathode (substrate).
So can it be any paint, or does it have to be a specific one?

Furthermore, I have seen that cataphoresis is a good primer. Is that true in every case?

Last question : Can we paint a cataphoresized substrate a long time after the cataphoresis have been done, only after degreasing it ?

Thanks for your answers,

Ludovic Dumont
- Paris, France

October 2017

A. Hi Ludovic. We added your inquiry to a thread on the subject which might clear up some of your questions. I'll offer you my book knowledge, but with hope that a reader with significant real-world experience will correct me :-)

Most electrophoretic coatings these days are cataphoretic, so the acronym CED (cathodic electro-deposited) coatings is widely used. I do not agree that all CED coatings are either black or white, but it is common to deposit white coatings and then apply "post-dyes" to get gold or other colors. Epoxy, polyester, and probably other CED coatings are available.

49008-1cedgoldb 49008-1cedgolda
(CED coating with gold colored post dye; same part, different lighting)

Regular paints cannot be used because the process is not like electrostatic spraying, where the electricity is used only for attracting the paint; rather electrons coming from the cathode actually convert the paint ions to a different material. One of the beauties of the process is that this converted and deposited paint is insulating, which directs the electricity to any uncoated area for a smooth, consistent finish with full coverage.

CED coatings make very good primers because they offer that full coverage, but some CED coatings are final finishes or bases for polyurethane clearcoats. It's common to call the coatings electrophoretic lacquer when they serve as a final finish.

The question of whether a CED primer coating can hang around for a long time and then require only degreasing before subsequent paint or powder coating layers are applied may be looking at the question from slightly the wrong direction. The issue is that subsequent coatings can only get full adhesion onto clean parts. If the parts can be kept clean it should be no problem, but whether "degreasing" is sufficient to clean dirty parts can be an open question. Good luck.

Regards,

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

December 7, 2017

Q. Hello,

Thanks a lot for all your answer.
I will have a last question about cataphoresis, a bit more difficult :
Is cataphoresis process likely to leave chloride ions on the coated parts' surface ?
I ask the question as the salt tests we perform on our parts before painting are abnormally high.
Can it be due to the bath (which should be electrically charged) ?

Thanks again for your time !

Ludovic Dumont [returning]
- Paris, France

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