Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Can paper mill's galvanized fence be powder coated?
Q. The fence of our company was hot-dipped-galvanized, but as the colour is not attractive, I want to apply powder coating on it. What are your suggestions? Do you think that the bonding between galvanized area and the powder coating is good enough?
Sugiharto Budidjajapapermill - Surabaya, Jawa Timur, Indonesia
2003
A. First you have to strip the old coating off. To the clean substrate apply a product called One Pack Etch Primer obtained from your local wet paint supplier. Apply a POLYESTER POWDER and bake.
Terry HicklingBirmingham, United Kingdom
2003
Q. . Thank you very much for your response. As the fence was newly galvanized and installed, is there any other way that we can do than removing the galvanizing material in order to prepare the fence to be powder coated?
Sugiharto Budidjaja [returning]papermill - Surabaya, Jawa Timur, Indonesia
2003
A. I disagree. You do not need to take off the galvanizing. A competent zinc phosphate based pretreatment (at least 8 stages) and polyester powdercoating over is OK.
We do this all the time, specializing in powdercoating galvanized steel. We only powder coat steel, and 90% galvanized, mostly by our own galvanizing plant. The key to this is the pretreatment in powder coating. Degreaser Acid etch, zinc phosphate.
With lots of hi purity rinses in between each stage.
Geoff Crowley
Crithwood Ltd.
Westfield, Scotland, UK
2003
1000 hours salt spray for powder coating over galvanizing, with no zinc phosphate?
Q. Dear Geoff Crowley,
is there any other process alternative to zinc phosphate? We need 1000 hours salt spray pass for polyester coating over galvanized substrate.
- Istanbul, Turkey
May 30, 2015
June 2015
? Hi Ates. What constitutes failure?
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
No failure related with process ... we'll decide investing for a process.
Ates Ucuncu [returning]- Istanbul, Turkey
June 25, 2015
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