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topic 24110

Kynar vs. Powder coating

A discussion started in 2003 but continuing through 2018


Q. I have four cast iron bollards scheduled to be installed (exterior) at our Harlingen Campus.
The department wants a Kynar Finish. I believe that a Powder Coating will provide an equal if not better finish and will last long.

I need data that I can use to prove my opinion. Can you help?

Tom J [last name deleted for privacy by Editor]
University - San Antonio, Texas


A. Dear Tom:

Kynar is PVDF based coating which is guaranteed for 20 years of environmental exposure. Normal powder coatings are nowhere near it - to the best of my knowledge. I am afraid, you may not find what you are looking for.

Gurvin Singh
Coatec India
supporting advertiser
Mohali, Punjab, India
coatec india


A. Hi Tom,

With the correct pretreatment and application, powder coatings are available with a guarantee for 25 year environmental exposure. These powder coatings have been available for a long time and are common in Europe. Hope this helps.

Drew Devlin
- North Lincolnshire, U.K.

June 4, 2009

A. PVDF or Kynar being a brand name, is a coating that can carry a lengthy warranty relating to color & gloss retention. A schedule of loss is applied to the product. Mechanical failure is generally not part of that. Warranties never apply to steel products. My advice is to sandblast the item white, handle minimally with clean gloves, Zinc prime, checking substrate temperature, powder coat with a finish product of SD quality polyester or TGIC free Sd polyester. Read any warranty. The 7 p's apply to powder coating. Prior Proper Planning Prevents Piss Poor Performance. Also know that Kynar or PVDF is not usually the recommended product on traffic & heavy contact areas by the reps I have dealt with. This comment is a personal opinion & not extended as fact.

Sheldon Pineo
- Fort Myers, Florida


Q. Would any one tell me more details about "Kynar" & its application..... thanks

Atul Bhide
Atul Bhide
jobshop / applicator - Mumbai, India

February 12, 2008

Q. Is Powder coating on steel as effective as on aluminum for preventing corrosion and maintaining color uniformity and luster? Exterior exposure.
For how long?

joe mercolino
ceilings - Los Angeles, California

February 13, 2008

Hi, Atul. Kynar is a powder coating, but it is thermoplastic rather than thermoset, and usually applied at far greater thicknesses than typical thermoset powder coatings. I have only seen Kynar coatings applied at one shop, so I am not really an expert on them, but they were applied from a fluidized bed rather than by electrostatic spray; my book knowledge supports that this is the typical approach.

Joe, please read Drew's entry very carefully because it implies some stuff that experts like him realize, but most people don't: it's all about the pretreatment! If appropriate and high quality powder coatings are applied to properly pretreated materials, the durability will be excellent. But no matter how exotic the paint or powder, if the pretreatment isn't good, the coating will be crummy. Steel parts require a well done phosphatizing step and possibly electropainting before powder coating. Good luck.

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

June 28, 2008

Q. What is the difference between thermoset and thermoplastic treatment for powder coating?

zia ullah khan
- Dubai . U.A.E.

July 2008

A. Hi, Zia. Thermoset plastics are plastics that cure into a different state than they started in. Sort of a one-way street. Once they are set they can never return to their original condition, you can't usefully melt them. Thermoplastic materials are plastics that soften with heat, repeatedly. If you formed a block of thermoset plastic, it would stay in that shape forever; if you formed a block of thermoplastic material you could, in theory at least, form it into a different shape the next time you applied heat.

When it comes to using these plastics in powder coating, the biggest differences seems to be that thermoset materials can be thin (a few mils) whereas thermoplastic coatings are much heavier; and thermoset materials are usually applied by electrostatic spray, while thermoplastics are usually applied by fluidized bed.


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

February 5, 2013 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Difference between PVDF, polymer and polyester coating? I am new in metal roofing industry and I would appreciate if anyone can enlighten me on the above differences and advantages.

Thanks in advance.

Tommy Kang
- Singapore



PVDF fluoropolymer based coatings are suitable for corrosion protection and making up to 15 mil film thickness. Teflon is a largest manufacturer of this type of coatings. Best luck.

D Kalyan
Calcutta, Mumbai, India

July 25, 2013

Q. We are considering the use of steel metal cladding and roofing paneling with a Kynar 500 finish for some small utility buildings in an industrial process facility. What are the effects of fluorides, both particulates and gaseous, on Kynar 500 coating? Can we expect the coating to last 5 years, 10 years? Maximum levels of particulates 12,500 ug/m3 per 24-hour period.

Randy Hansen
- Phoenix, Arizona, USA

July 29, 2013

A. Yes, if installed properly and well maintained it should last 5-10 years, maybe a little longer per BS4994. Halar (ECTFE) might be better but it is fairly expensive.

blake kneedler
Blake Kneedler
Feather Hollow Eng.
Stockton, California

August 8, 2013

A. This thread is a little convoluted, so I answer what appears the central question. Kynar is a PPG trade mark for a PVDF resin system. PVDF is a fluorocarbon based polymer which when it comes to things like weathering properties is at the top of the food chain. This is why many architects specify it for buildings. Polyester is more of general purpose resin system used for more mundane, less critical, painting. Powder coating is paint that is applied without the use of solvent, though different resin systems can be used, including polyester.

When it comes to things thermoplastic to thermoset you learn quickly if you have a chemical like MEK on your hand don't pick up a phone or a plastic stopwatch, no chemical resistance.

Ronald Zeeman
coil coating - Brampton Ontario Canada

Powder Coated Aluminum vs. Galvanized Metal with Kynar for Commercial Railings in Coastal Environment

May 20, 2014 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. We are looking to install new railings at a hotel in the harsh coastal environment on the Monterey Peninsula, California.

We have a lot of linear feet of railing (so cost/value is a consideration) and I'd like the railings to be modular or built off-site and we can "simply" install on site.

One architect has recommended a modular, powder coated aluminum railing product, and another architect has recommended galvanized metal with Kynar paint.

I'm concerned by some images I've seen of the powder coat flaking off on aluminum. I have no experience with Kynar.

Any thoughts or recommendations? THANK YOU.


Greg Alden
- Monterey, California

May 2014

A. Hi Greg. I think you can pick the railing material you wish (galvanized or aluminum), independently of which final finish you want (Kynar or a more mundane powder coating). I think I'd mix-&-match and go with the Kynar on the aluminum. But Kynar on galvanized should last the better part of forever.

A point we should continue to repeat in case there are any newbies reading this posting is that pretreatment is critical -- not only will the paint not stick properly to the aluminum if not pre-treated well, it will pull off the galvanizing in sheets :-)

Zinc phosphatizing is required for the galvanized, and chromate conversion coating for the aluminum. Best of luck.


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

May 21, 2014

Q. Thank you for your response.

With powder coating, I understand that you can't easily "repaint" it or touch it up if it gets scratched or if color palettes change in the future.

With a product like Kynar, can we paint over the original if we want to change the color in a few years or if it gets scratched or worn out?

Greg Alden
- Menlo Park, California United States

May 2014

A. Hi again. Anything can require touch-up, and consequently there are touch up materials for either finish, although the touch-up may not have the durability and longevity of the oven-cured finish. Repainting of either to accommodate color changes is probably a pretty big deal, best avoided, but farmed out to experienced parties if necessary. Firms who offer both, like the site's supporting advertiser, Southern Aluminum Finishing, can probably advise the details of repainting the various finishes.


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

Paint touch up on PVDF coated steel door

October 21, 2017

Q. Hai sir
Here we have some PVDF coated steel doors (RAL 1013). Now, due to some heavy work on site, there are lot of scratches on the PVDF coated doors. Can anyone please advise me how to do paint touch of same colour on the PVDF coated door? I'm expecting your positive replies soon, thank you.

saravana kumar
- Qatar

October 19, 2018

Q. On a salt water boat, which will be a better product on T-tops, rails, etc? They complain that powder does not hold up very well. Would Kynar be a better choice?

Eric jones
painter - ft.pierce, Florida

October 2018

A. Hi Eric. Kynar will outlast powder coating, but please remember that preparation/pretreatment provides about 80% of the durability and the paint/powder about 20% :-)

Are these T-tops, rails, etc., made of aluminum? If so, they should be properly prepped and chromate conversion coated (Alodine, Iridite, Mil-DTL-5541 [link is to free spec at Defense Logistics Agency,]) before painting or powder coating. Best of luck.


pic of Ted Mooney
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Striving to live "Aloha"

October 22, 2018

Q. What is the best and friendly way on the environmental to pre-clean before coating. The EPA is my big concern on haz/mat waste.

eric jones [returning]
auto care center - ft.pierce, Florida

October 2018

A. Hi again Eric. EPA regulations are generally "categorically" based, meaning that an auto care center will have regs that are different from the regs a plating shop has, or a high school has, or an aluminum fabrication shop has, or other categories of businesses have. So you need to figure out exactly what category your business falls into.

Regardless of any of that though, aluminum should be non-etch cleaned, etched if necessary, desmutted/deoxidized, and chromate conversion coated. There are now chromate conversion coatings which comply with Mil DTL-5541 (meaning that they have been proven to offer good adhesion and good corrosion resistance) but which are free of hexavalent chromium (Type II coatings). These go by the slang name TCP (trivalent corrosion prevention) coatings, and are considered environmentally friendly.

I'm not saying you can't prep and paint these parts yourself, but usually such parts are handled in treatment lines which involve immersing the parts sequentially in tanks full of the chemicals I mentioned (with rinsing between each step).


pic of Ted Mooney
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Striving to live "Aloha"

October 23, 2018

Q. What is the best way to wash aluminum to be Kynar coated. I don't want any haz/mat martial left over to deal with. Would like to send down city sewer system.

I am going to open a plating shop and I have boat Manufacturing all around me. And I have two powder coating places. But they don't use Kynar. I asked you about this already. And washing the parts and disposal of the chemical after it's done is my concern. I would like to put it the the city sewer system. If it safe to do that? Trying to get my cost up front Eric jones [returning]
owner - ft.pierce Florida,

October 2018

A. Hi again Eric. The EPA enforces discharge and performance standards on your local POTW (publicly owned treatment works / sewer system), and they in turn enforce standards on the businesses discharging to them. Basically you are not allowed to discharge to the sewer except in accordance with your discharge permit. So your best next step is probably to contact your POTW and find out what "category" they consider you to be and what the effluent limitations for that category are, and start applying for a discharge permit.

It is a possibility, but not a sure thing, that you can discharge all of your pretreatment and (non-hexavalent) chromate conversion coating wastes to the sewer under the terms of your permit. There are probably things like necessary solvents, stripping solutions, dregs from your paint drums, etc. which you cannot discharge but must have hauled by a licensed disposal company ... and there may be regulations regarding accumulation & storage of these wastes. Environmental permits are unfortunately not a simple, cheap, straightforward thing -- which is why there are environmental consultants and attorneys in every geographical area. Best of luck.


pic of Ted Mooney
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Striving to live "Aloha"

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