Ornamental Iron Fence & Rails

Date 12-01-2003 03:02

I cant speak for all powder coating shops but in our part of California, the shops sandblast the parts, then degrease and dry them before spraying on the powder and baking them. I've had several thousand parts powder coated (most of which have been aluminum, however) and no primer has ever been applied beforehand. I've watched steel parts being coated and I've not seen any that were preprimed. A primer may actually impair the coating process since some primers may soften and wrinkle at the temperatures used in their baking ovens (around 500 deg. F.) The shops can vary the final thickness of coating but it also depends on the type of powder coating finish ordered. Your contractor should be the one who specifies not only the color but also the type of coating (e.g., epoxy, vinyl, etc). If he has not provided any exact specifications, you should ask a competent coating firm for their recommendation for these parts. Epoxy coating, for example, would not usually be a good choice for this poolside use since sunlight eventually makes epoxy coatings chalky.

By thcqci

Date 12-01-2003 13:31

We have had pieces powder coated. On one project, the contractor applied a primer with the powder coating process and then applied a top coat. This was exterior guardrails and handrails. Looked great when it was done.

http://www.powdercoat.com/ and http://www.pcoating.com are 2 places to learn more about powder coating. Very interesting process.

By mcwelding (**)

Date 12-03-2003 13:20

hey seahawk,
my buddy builds many fences, gates, railings. no primer, they sand blast and powdercoat. just clean off the berrys

By thcqci

Date 12-03-2003 16:54

Just to add to my thoughts earlier, one requirement that the powder coat contractor had was we were to deliver the steel cleaned to SP-6 or better, preferably SP-10. They did not have the capability to blast and the chemical processes would not remove corrosion either. It would only remove oil, grease, etc. They would not warranty any of the coating if the steel was not adequately cleaned.

The primer referenced above was applied with the powder coat process. If memory serves me, it had a high zinc content. It was specified by some coating engineer somewhere as it was going to be outside, near an oceanfront environment. Powder coating was specified because the open mesh (6" x 6" x ¼" wire mesh) could be coated with less drip or run worriesand less waste using the powder coating process than a standard sprayed on coating. It worked well and looks great even after a couple of years in service.