SPCC POWDER COATING SPEC

[imagineers]

I have designed a sheet metal assembly out of SPCC steel sheet, with a few parts welded together. it may be used in a saltwater environment, and the coating should be able to handle that. I have no idea what to spec on the assembly for powder coating. I currently
spec'd powder coat polyurethane, smooth flat matte black, 0% gloss. would this be a valid spec? it will be sprayed in china, and they originally said SPCC painted black
but I want to clarify the coating and use powder coat rather than just say painting, thoughs?? or maybe like a TGIC free polyester coating maybe? and what should I spec on the drawing?

 

[TVP]

Not nearly enough details on the environment. Will it be immersed or just "exposed"? For how long? If you want any kind of lifetime out of this, the surface protection needs to be outstanding:

perfect cleaning
preferably zinc plating followed by
pretreatment with zinc phosphate (includes a sealer after phosphate)
thick epoxy coating followed by
thick polyurethane coating

Even with this, any small defects in the coating will lead to rapid corrosion. Most things that require resistance to saltwater exposure are either hot dip galvanized or made out of corrosion resistant alloys (stainless steels, nickel alloys, titanium, etc.).

 

[MadMango]

Since this is being done in China, I would also provide the powder coat manufacturer's information. If it is not specified, you may get an incorrect quality and color results.

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of these Forums?

 

[imagineers]

it will not be emersed in saltwater at all, more from sitting in a server environment that may or may not be close to a saltwater environement like california or maybe florida. Not sure of the control in the server rooms themselved, I just want to be on the safe side with potential higher humidity. Another thing I am trying to ensure is an UL94V-0 fire type rating, and I cannot find any rating on polyurethane powder coat for that. Not even sure if matte black polyurethane is the spec to use???

 

[CoryPad]

Will this be outside and exposed to salt spray/mist? If so, then the coating described above (maybe without the zinc plating) would be a good start. Maybe use a zinc-rich epoxy base coat.

 

[imagineers]

I wanted one coating that is corrosion resistant and also UL94V-0 safe also