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E-coating vs. Powder Coating vs. E-coating Plus Powder Coating

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Q. I am a paint technologist and wanted to know the difference between An electrodeposition coat vis-a-vis powder coatings. Which one is superior in terms of following.

1. Impact Resistance.
2. Salt Spray Resistance (ASTM B117 [link by ed. to spec at TechStreet] )
3. QUV Testings :- 313 Nm lamp , UVB light 300 Hrs. total test duration having 4 Hrs. of Uv AND 4 Hrs. of the condensation cycles at regular intervals. Any specific cost saving due to the process.

Regards,

VAIBHAV KULKARNI
- MUMBAI, MAHARASHTRA, INDIA


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A. Theoretically, they are both electrodepositions. Both achieve the same end - an organic coating on a metal substrate. Only the method of transferring the organic layer is different. In powder coating the powder particles are charged. In E-coat the liquid is charged and an electrochemical reaction deposits a film. Both have to be baked for crosslinking. Both are available in epoxies and PUs. Both have their own advantages and disadvantages.

To compare the parameters you will need to match the technologies. Epoxy or PU. That is fairly complex to be answered here.

Gurvin Singh
Coatec India
supporting advertiser
Mohali, Punjab, India



To minimize searching and thrashing, and to provide multiple points of view, Finishing.com combined formerly separate threads into the single dialog you are now viewing. Please forgive any resultant repetition.



Powder coater losing huge contract to e-coating

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Q. We are faced with losing 30 million dollars in sales due to competitor quoting finishing the components in lower cost e-coat vs. our current powder coating. We manufacture and install commercial vehicle cargo interiors. Our components will be used in everything from Telecommunication to heavy construction and the finish needs to stand up to the equipment being placed on and off our powder coated shelves and components. We feel by powder coating our components vs. e-coating it gives a more durable surface and longer finish life. Does anyone have any test or study information where e-coat has been tested against powder coating? We are using a non UV-resistant polyester-epoxy powder coating.

J. Michael C [last name deleted for privacy by Editor]
1st tier automotive, point of purchase displays - Atlanta, Georgia


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A. Hopefully, you will get some help here ... and you can contact the Powder Coating Institute and vendors such as Tiger Drylac and Martex to see what literature they can offer, Michael.

But personally if I had 30 million dollars in sales at risk in these circumstances, I wouldn't consider those options for a heartbeat if I hadn't already retained an expert powder coating consultant to prepare a report tailored to my exact product line. Best of luck.

pic of Ted Mooney
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


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Q. What is "e-coating" as mentioned in your mail ... thanks.

Atul Bhide
Atul Bhide
jobshop / applicator - Mumbai, India


May , 2007

A. Hello, Atul. E-coating means electrocoating -- sometimes alternately called electropainting, electrophoretic lacquering, CED (cathodic electrodeposition) and so on. The parts are immersed in an electrified tank with a special cationic or anionic paint which deposits on the parts as a result of electrochemical oxidation or reduction analogous to electroplating.

An advantage is full and even coverage -- the deposited paint becomes an insulator, diverting the electrical current to spots where paint hasn't yet deposited). Another advantage is that the coating is quite thin compared to other organic coatings. But that thinness might be a mark against it for durability and corrosion resistance. The two processes can be combined, i.e., electrocoating followed by powder coating.

pic of Ted Mooney   Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey

Electrocoating: a Guidebook
for Finishers




High Performance Powder Coating



May 6, 2009

Q. Advantages of electrocoating over powder coating.

praveen kumar
employee - chennai,Tamil nadu, India


August 31, 2010

A. Hi, Praveen. We appended your inquiry to a thread which may offer some general insight for you. If you provide a few paragraphs of additional detail about your components and their application, readers may be able to provide additional info tailored to your situation. Our experience is that readers never spend their time responding to a dependent clause :-)

Regards,

pic of Ted Mooney   Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



Best finish for aluminum outdoor luminaire

January 24, 2012

Q. Hello all,
E-coat vs. powder coat for an outdoor luminaire? Trying to address the finish on a diecast aluminum outdoor luminaire. Current finish is anodize with powder coat over the top. VERY expensive. Any suggestions on a finish that will withstand weathering (looking for 10 year warranty)?

David Venhaus
Consultant to OEM - Wauwatosa, Wisconsin

January 24, 2012

A. Hi David.

Anodizing diecast aluminum and following it with powder coating sounds like a good but fairly unusual and (as you mention) expensive finish. I suspect that e-coat PLUS powder coat will be less expensive and more robust. Please remember, however, that pretreatment is a major part of finishing, so it's not just an issue of specifying the final finish, but either specifying the pretreatment or finding competent applicators who supply good pretreatment as a matter of course. Good luck.

Regards,

pic of Ted Mooney   Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


January 25, 2012

A. A possible even cheaper process whilst still retaining 10 years protection would be zirconium phosphate followed by architectural polyester powder top coat.

Terry Hickling
Birmingham, United Kingdom


July 2014

thumbsup2I like Terry's suggestion providing that the geometry of the luminaire is sufficiently simple that full coverage can be guaranteed.

Regards,

pic of Ted Mooney   Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



E-coating for swimming pool filters

February 15, 2012

Q. Hi all,

We need to protect some tubular heaters that are going to be used in a swimming pool environment (fitted at high level) and have suggested the use of e-coat. The tubular heaters are manufactured from mild steel.

Our client has asked for some data to support the choice of e-coat. Can anyone point me in the right direction?

regards

Gary

Gary Langman
- Daventry, UK


February 14, 2012

A. Hi, Gary. We can tell you that all automobiles around the world are e-coated before painting, so that should be some evidence of its value. PPG may have case studies. But I think you will find that most E-coating is not UV resistant, so it must be followed with something. A polyurethane top coat is common, but I think polyester powder coating would be better.

Again, the primary thing that E-coating offers, that painting and powder coating don't, is thinness and 100 percent coverage. Good luck.

Regards,

pic of Ted Mooney   Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



February 15, 2012

Q. I am in the beginning stages of restoring an old pick up truck. I'm having the frame repaired and reinforced, being a midwestern truck, from the Salt n' Rust Belt... I want to take whatever steps I can to prevent the frame from being ruined again. From what I have been reading, it would appear that having the frame cleaned, then e-coated, then powder coated is the way to go? I want the best protection possible - whatever method it might entail. Comments saying E-coating is able to offer 100% coverage, but is thin... tend to concern me. Powder coating is a thicker more durable process correct? But is not able to offer 100% coverage... but the two together - would that be good enough? Opinion, thoughts, suggestions?

Thank you!

Tom Stack
- Stevens Point, Wisconsin, USA


February 16, 2012

A. Hi Tom. Yes, the two coatings are compatible, and electrocoating followed by powder coating is a common and very robust system.

Regards,

pic of Ted Mooney   Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



Need 1300-1400 hours salt spray resistance with powder coating

July 8, 2014

Q. Sir, can we increase Salt Spray resistance by using super quality (durable) powder? We have requirement of 1300 to 1400 Hrs SST. Another system, CED coating, is available but can we use only powder to increase SST hrs?

Jeetendra Borse
- Ahmednagar, Maharashtra, India


July 2014

A. Hi Jeetendra. If the shape of the parts is simple enough that you can get full coverage, with no pinholes or thin spots, and you have a robust pretreatment system like zinc phosphate, I think you should be able to get those hours from powder coating.

Regards,

pic of Ted Mooney   Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



February 25, 2015

Q. Hi
I would like to know the reasons why a component would fail in the Impact test for powder coating done over CED coating.
We have been doing CED for more than a decade and are facing this problem just lately for only one of our customers who get their jobs powder coated after CED.
All other parameters for CED like SST, Adhesion, etc. are Okay and there is no change in the process but we are getting this problem only after the powder coating is done over CED.

Please help any suggestion/comment will be extremely useful to pin-point the exact problem.

Thanks,

JANHAVI SINDHU
plating shop owner - PUNE,MAHARASHTRA,INDIA
  ^- Privately contact this inquirer -^


March 12, 2015

A. Check the cure schedule of the powdercoater.
Perhaps there is an over-bake issue?
Hope this helps,
Bill

William Doherty
Trainer - Newcastle, NSW Australia


April 1, 2015

A. Bake your E D coated coated parts at higher temperature than powder coating. This will solve your problem for sure.

Avinash Vidhate
- Naik, Maharashtra, India



June 13, 2015

Q. Dear CED Experts,

I am new to this field of CED, Powder coating or painting.

Please advise me...
1. Which process is better, CED or Powder Coating for Truck or Bus Chassis.

2. Is it done before riveting / Bolting or after the whole frame is ready.

3. What is the coating thickness for Truck or Bus Chassis

4. What is the approximate per square inch cost of CED and Powder Coating for 8 Meter long chassis

Regards,

Jagdip Punia
- Gurgaon, Haryana, India
  ^- Privately contact this inquirer -^


June 15, 2015

Q. Hi Friends,

Recently I came to know that there are certain CED processes which meet the final Paint specifications, i.e., we do not need to do Primer, Top coat, etc.

Is there any such Technology called "Finish CED"?

If so, who is doing that? Please help.

venkat prabu
- chennai, India
  ^- Privately contact this inquirer -^


June 19, 2015

A. Jagdip,
You didn't mention what spec you are trying to achieve. You also did not mention anything about pretreatment.
The CED and powder will only be as good as the conversion coating that is beneath them.
In my opinion, the best combination is a zinc phosphate pretreatment with a cationic epoxy e-coat primer AND powder.
The chassis can be e-coated with or without rivets and bolts. You'll need to consider masking and will also need to consider drainage as the chassis gets more complex.
Your paint supplier should be able to address film build and cost.

A. Venkat: The end use of your product will determine whether e-coat should be used as a top-coat. Cationic epoxies offer excellent salt spray performance but have poor UV durability. Acrylics have good UV durability but do not perform as well in salt spray.

Dan Mack
- Horicon, Wisconsin


June 19, 2015

Q. Please clarify what cost should be more -- Powder coating or CED coating (all the pretreatment process starting from Degreasing to Zn Phosphate will remain same)?

ARIJIT DAS
- JAMSHEDPUR, JHARKHAND, INDIA


June 2015

? Hi Arijit. Please tell us what the parts are that you wish to coat (application, size & shape), and what the production situation is (x parts per hour, y hours per day, etc.)

Regards,

pic of Ted Mooney   Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


June 21, 2015

Q. Parts are 2 foot hollow tubes of 1 inch dia., production 200 per 8 hrs; shapes are a little bit bent (Turning Tubes of trucks. Please suggest which will be the best cost effective coating having same Zn phosphate pretreatment--CED coating black or Powder coating black.

ARIJIT DAS
- JAMSHEDPUR, JHARKHAND, INDIA


June 2015

A. Hi again. 200 parts in 8 hours is 25 per hour or one every 2.4 minutes. This is a modest production rate and manual powder coating would probably be fine. It's also a low production rate for e-coating -- if the rack held, say, 4 or 5 parts, you'd only need to process 5 or 6 racks per hour. But you could integrate the e-coating with the phosphatizing, and probably would not be as easily able to integrate the powder coating with the phosphatizing.

My own feeling is that e-coating would be slightly less labor intensive, slightly less expensive in materials, and slightly more reliable (free from defects). The e-coating equipment would probably cost more, so you would need the production run to last long enough to offset the capital cost difference.

Second opinions welcome, especially from anyone who has done both :-)

Regards,

pic of Ted Mooney   Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey

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