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Question on powder coating
Posted by: cepak ()
Date: November 27, 2017 05:28PM

Can you paint over powder coating and will the paint stick or will it peal?


Tom Cepak
DFW, TX

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Re: Question on powder coating
Posted by: vairmech ()
Date: November 28, 2017 04:09AM

Since powder coat is a plastic of sorts I would think that the plasti-coat paint would work with a thorough cleaning and maybe a light scotch brite pad.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Question on powder coating
Posted by: vacorvairlover ()
Date: November 28, 2017 09:45AM

Good Afternoon,

Powder coat is still paint, if you wish you want to paint over it you would need to prep it just like anything else. you can use a self etching primer first or sand it lightly then prime and paint. Note trying to sand a good powder coating may be a little more difficult than your normal paint.

John Garrison
Roanoke VA.
1964 corvair spyder convertable
1965 Corvair Monza 110 auto coupe soon to be my daily driver
2014 Ram 1500 5.7L Hemi
2018 Re-designed Jeep Compass Trailhawk

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Re: Question on powder coating
Posted by: BobV66Vair ()
Date: November 28, 2017 09:50AM

Second that. I recently powder coated the tins for my engine and one came back flawed. I had to have it sand blasted to get the coating off. I first tried it in my HF bead blaster with iron oxide (hard stuff) and it didn't make a dent.

Bob Vinnacombe
Sandy, Oregon
1965 Corsa 140 stock
1966 Monza Soon to be race car
1968 Monza Parts for now

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Re: Question on powder coating
Posted by: vairmech ()
Date: November 29, 2017 03:55AM

This is probably more than you wanted to know! While you spray it like a paint it is more like a plastic than conventional paint.

TYPES OF POWDER COAT

There are two different types of powder coat - thermoplastic and thermoset. Thermoplastic powders melt and flow when heat is applied but they continue to have the same chemical composition once they cool and solidify.
They are generally applied to a surface that has been preheated to a temperature significantly higher than the melting point of the powder. As a thermoplastic powder material is applied to the hot surface it will melt and "fusion bond" to the surface and then "flow out" into a strong, continuous film. As the film cools it develops its physical properties. Nylon powder coating materials are the most commonly used thermoplastic powders.
Thermoset powder coatings also melt when exposed to heat, but they then chemically cross-link within themselves or with other reactive components. The cured coating then has a different chemical structure than the basic resin. Thermosetting coatings are heat-stable and, unlike thermoplastic powders, will not soften back to liquid phase when re-heated.
Thermosetting powders are derived from four generic types of resins: epoxy, acrylic, polyester and fluoropolymer. From these resin types, several coating systems are derived. Resins used in thermosetting powders can be ground into fine particles necessary for spray application and a thin film finish. Most of the technological advancements in recent years have been with thermosetting powders.
Thermosetting Powder Coatings
EPOXY resin is a hard, impact resistant interior only formulation. For the most part, epoxy coatings are used as functional coatings for substrate protection where corrosion resistance, impact resistance, and adhesion are essential. The primary limitation of epoxy-based coatings is poor weatherability. Typical applications include industrial equipments, automotive underbody components, metal furniture and appliances.
ACRYLIC resins are typically used in the automotive industry as a clear coat on materials. Acrylic creates a smooth clear coat with very good clarity and provides a hard surface that is highly chip-resistant. Acrylic resins are used as additives to promote improved flow and leveling as well as enhanced stain and chemical resistance in polyester hybrid, polyester TGIC, and polyurethane powder coatings.
POLYESTER powder coats are the most used of all powder coatings in the U.S. market. Polyester's offer a broad application field and many different chemistries including: Polyester/TGIC (triglycidyl isocyanurate); Polyester/TGIC-free; Super-durable Polyester and Polyester Hybrids. Some Super-durable and Hybrid Polyester resin systems meet the AAMA 2604 specification.
FLUOROPOLYMER resins are top of line for exterior weatherability and UV stability in both powder and liquid coatings. Fluoropolymer powder coatings are purposely tailored for the architectural market and offer a long-life durable finish. Fluoropolymer powder coat resin systems can be formulated to meet the requirements of the high performance AAMA 2605 specification.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Question on powder coating
Posted by: Mel ()
Date: November 29, 2017 07:58AM

powder coating thumbs downsad smiley forget it , had some 60 Impala parts done .....never again sad smiley

Orangeville, Ontario. CANADA

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Re: Question on powder coating
Posted by: American Mel ()
Date: November 29, 2017 08:33AM

I find this statement ironic.

" The primary limitation of epoxy-based coatings is poor weatherability. Typical applications include industrial equipments, automotive underbody components, metal furniture and appliances."eye rolling smiley

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WA. state, 1 mile south of the Canadian border,
I am not at the end of the world, but you can see it from here.
'66 Monza Coupe - 4spd, 140 Daily driver beater
'67 Monza Vert. - PG, 140 Daily driver beater
'67 A/C Moredoor Monza - 140 4-spd. driver

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Re: Question on powder coating
Posted by: alpinemetal ()
Date: November 29, 2017 11:41AM

We're dealing with this on a commercial project where the owners didn't like the color of some downspouts installed at a prison. PPG recommended preping the surface with 80 to 100 grit and using a 2 part marine grade urethane paint.
Good luck

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Re: Question on powder coating
Posted by: tony66 ()
Date: November 29, 2017 02:03PM

I had some parts powder coated with a bright silver color. I commented to the powder coater that I wanted to retain the brightness, and he suggested that we spray a clear coat over the parts. The urethane clear adhered just fine without any prep on the powder coat, but it reduced the silver's brightness. I had those parts for over 5 years before I got rid of them. Over that time, I never saw any pealing or adhesion issues.

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Re: Question on powder coating
Posted by: Melb-Mike ()
Date: November 29, 2017 06:00PM

I'm not what type of powder coating the PO used on some of my engine tins but it was as hard as a ceramic surface. I managed to scuff it enough to coat it with paint but it was a chore. I don't think I could have scratched it with a screwdriver. If it had not been painted red I might have left it alone. The one aspect of powder coating I don't care for is the orange peel finish, reminds me of the inside of our ovens. By the way I tried to bead last the tins with a medium grade and a coarse grade glass beads without success. Tough stuff.

64 Greenbrier
64 Spyder (needs restoration)
65 Corsa 140, restored
66 Corsa turbo, restoring now
66 Corsa 140 "RR" code coupe fully restored
67 Pontiac GTO restored
69 Corvette 427 convertible restored
2015 Porsche Panamera S
2015 Corvette Z06
1965 AC Cobra (Factory Five)

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