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Industry specs for powder coating thickness and testing methods?

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Q. I need to know what are the industry specifications for powder coat thickness.

Larry J [last name deleted for privacy by Editor]
process engineer - Elkhart, Indiana


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A. That is a tough one to give a general answer to, Larry, since the coatings could go as thick as 20 mils or even more for thermoplastic coatings applied by fluidized bed, or as thin as a couple of mils or even one mil for polyester coatings applied by electrostatic spray. What kind of parts, and what kind of exposure conditions?

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


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A. The application method is electrostatic spray. The environment is best described as indoor laboratory. What I am trying to determine is how much mechanical tolerance I need to accommodate this type of finish or what are reasonable coating thickness tolerances can I give to the finisher.

Larry J [returning]
process engineer - Elkhart, Indiana


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A. The standard film thickness for a standard powder coating for optimum mechanicals is between 60 and 80 microns (~2-3 mils).

Hope this helps,

Drew Devlin
- Lincolnshire, U.K.


October 7, 2008

Q. Is the 2-3 mil. thickness also the industry standard for powder coated deck rails? If not, what is the desired industry standard for that application?

Darryl D [last name deleted for privacy by Editor]
- Grants Pass, Oregon


May 4, 2010

A. AAMA specifies coating film thickness not less than 30 microns, and British standard 40 microns above, powder coat supplier specifies 60-80 micron for architectural powder coatings.

Ganapathy [last name deleted for privacy by Editor]
- Singapore



January 17, 2013

Q. Dear sir,

Please mention the standard document for powder coating thickness?. It is required for our ISO document.

Thanks,
Umesh

Umesh Devadiga
- Bangalore


January 17, 2013

A. Hi Umesh. The product line you are referring to is deckrails, and the coatings are polyester, correct? And you presently refer to no spec at all when you place powder coating orders?

Regards,

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


January 24, 2013

Q. Dear sir,

I'm referring to powder coating for industrial racks. For our audit purpose, I want to show them standard practice for Powder coating will be 60-80 microns. But I'm unable to get any standard documents or files for above matter. Please suggest me the documents or person?

Umesh Devadiga
- Bangalore, India


January 26, 2013

A. It is best to seek advice from the specific Powder Manufacturer for the product and especially the colour you are using.
60-80 microns is a good general target.
You will find, however, that different formulations from different manufacturers for different colours will vary widely.
Probably a good example of this would be to look at, say, Safety Orange.
A TGIC resin, Lead Pigmented Polyester Powder would probably be okay at 60 microns.
An Amide technology Lead & Cadmium-free Polyester Powder would almost certainly be translucent at 60 microns.
The trick there is to maximise opacity by thicker film build but avoiding orange peel.
Reds, Yellows & Oranges are the problem children.
Hope this helps.
Regards,
Bill

William Doherty
trainer - Soldiers Pt., Australia


January 31, 2013

thumbsup2Thank you for your information

Umesh Devadiga
- Bangalore, India



June 11, 2014

Q. We're using polyester powder and I got a reading 100-200 Microns [ed. note: i.e., 4-8 thousandths of an inch]. Is there any effect for the integrity or the coating value?

Fer Castro
- Dammam, Saudi Arabia


June 2014

A. Hello Fer. This is about 2 to 4 times as thick as usually employed. To my knowledge it should not be troublesome if fabrication is finished, whereas it might be a problem if the powder coated parts are to be formed after coating. But I'm not a powder coating expert, and will be happy to defer to any other answers you get.

Regards,

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


June 19, 2014

A. I refer to my earlier 2013 response to a very similar question which is posted to this thread.
At the thicknesses you describe it is almost certain that you are experiencing "orange peel" effect with polyester powder.
I assume that you are referring to standard Polyester powders?
If you are not worried about aesthetics there should not be a problem.
If you are referring to Thermoplastic or Fusion Bond Epoxy Powders then there is usually no aesthetic factor and such film builds are regarded as acceptable and even desirable.
Hope this helps.
Regards,
Bill

William Doherty
trainer - Soldiers Pt., Australia



Standards for acceptance of powder coating

June 24, 2014

Q. Is there any standard (UL, ASTM, etc.) which shows the limit/acceptance value of powder coating?

Fer Castro
- Dammam, Saudi Arabia


June 2014

A. Hello Fer. Such specifications tend to be application related rather than arbitrary dictates offered in the abstract. For example, you can see architectural standards AAMA 2603, 2604 and 2605; and Australian standard AS 3715 [link by ed. to spec at TechStreet]; and tape tests ASTM D3359 [link by ed. to spec at TechStreet] and GM 9071P; and impact test ASTM D2794 [link by ed. to spec at TechStreet]; and there are many possible salt spray tests including xxx number of hours of ASTM B117 [link by ed. to spec at TechStreet] exposure; a rub test from the Powder Coating Institute (procedure #8); ISO EN2360; and Qualicoat standards for thickness.

Please describe your situation, product line, and exposure conditions and someone may be able to suggest appropriate standards and tests. Gardco and Tator have good books on paint and powder coating testing. Good luck.

Regards,

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



July 23, 2014

Q. We have received the product with coating thickness of 200 microns. The product is a LED lighting enclosure. There is no bending operation after this process. We find the product is okay on peeloff test. Can we use it?

PRAKASH. KANAKOOR
- MYSORE, KARNATAKA, INDIA


August 7, 2014

A. Your question is posed without sufficient back ground.
Is the powder thermo-set or thermo-plastic?
What are you describing by: "peel off test"
Are you referring to an adhesion test?
In all, there are too many unknowns in your query.
Please be more specific.
Define your application criteria.
Define environmental factors in service life.
Define type, grade & quality of powder.
Define substrate, pre-treatment & cure schedule.
I could go on but basically you need to give the whole picture if you expect any meaningful assistance.
Best Regards,
Bill

William Doherty
Trainer - Newcastle, NSW Australia


September 17, 2014

The powder coat thickness would likely be controlled in the US by mil standards (military standards). I believe your end usage would drive which standard would be required.

jean mcgovern
- sheboygan, Wisconsin usa



December 7, 2014

Q. I need what are standards of testing methods used in industry powder coating, and how to check the adhesion test in powder coating,

gopinath
Gopinath
- mumbai,maharastra,india
  ^- Privately contact this inquirer -^


December 2014

A. Hi Gopinath. Please read my earlier reply of June 2014 and try you best to explain your powder coating needs so people can suggest possible tests. As you see on this page, and in the referenced books, there are different resins, different substrates, different application methods and conditions, and different corrosion resistant needs, and it is very difficult to explain all of the possible testing needs, short of book length.

The Technology of Powder Coatings by S.T. Harris has a 20-page chapter well arranged by "Testing in the Development Lab", "Testing of Raw Materials", "Testing During Manufacture", and "Testing of the Finished Product" =>

Good luck.

Regards,

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

The Technology of Powder Coatings
by S.T.Harris



December 11, 2014

Q. I plan to buy / get manufactured 50 (hospital type) steel beds in 14 gauge (approx. 1.8 to 2 mm thk.) CRCA pipe sections to donate to an old age home. We plan to get them white powder coated. Kindly advise recommended thickness for reasonable durability (say to last 10 to 15 years). Would 50 micron be okay? How to easily check?

Anupam Suri
Retired - Gurgaon, Haryana, India
  ^- Privately contact this inquirer -^


December 28, 2014

Q. Is there any mathematical relation between the powder coating thickness and other input parameters such as dryer temperature, main furnace temperature and conveyor velocity. I want to know how those input value can be identified for particular coating thickness?

kannan paramasivan
park - coimbatore, tamilnadu, india
  ^- Privately contact this inquirer -^


December 31, 2014

A. There's not much relationship between those factors and coating thickness, though conveyor speed has some impact, but only where a conveyor is used (not all powder coating is done with a conveyor).
Varying the curing temperature doesn't change the thickness.

If you wish to change thickness of the coating, try varying gun parameters.

Geoff Crowley Geoff Crowley
galvanizing &
   powder coating shop
Glasgow, Scotland


January 8, 2015-- apologies, finishing.com misfiled this reply, and didn't post it until January 16

A. Well, this item is usually referred to as a "cure schedule".
Essentially it means time at metal temperature and is usually represented graphically.
There is very little change with varying coating thickness.
Hope this helps.
Regards,
Bill

William Doherty
Trainer - Newcastle, NSW Australia

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