Powder coated aluminium finish - Up to a marine environment?

[ganter]

Hello fellow seafarers,

I've had to ditch the original inside aluminium trims for the cabin lights/ windows in my old Westerly - too badly corroded, etc.



I've cut some new ones from 3mm Aluminium.

Question is; I wonder if I should have them powder coated white to bring the interior up to date a little (and hide my atrocious sanding and bevelling on the bare metal)

AND, most importantly; if I do, will the powder coating survive the ravages of the salt water environment (albeit "below") for more than a season or two?

As always, thanks in advance for wise answers.

Ganter.

 

[pvb]

Just how much salt water do you get below? Thought of closing the hatches?

Of course powder coating, or anodising, will help.

 

[Seajet]

Ganter,

I'm afraid I have my doubts that it will last, judging by car & motorcycle powder coating I've had.

I treated my alloy rubbing strake tracks with Dulux ' Metalshield ' which worked very well, think it comes in silver or white, 1 part but requires the 1 part Metalshield primer.

Far and away the best metal paint I've ever used ( and I've tried a lot ) inc for my steel keel; don't be put off by the ' Dulux ', this stuff is the business.

 

[Tranona]

Powder coating is often used in this type of application as it is easier to get a good finish rather than spraying or hand painting. It will last indefinitely inside.

 

[RichardTaylor]

Going back to my metal finishing days, aluminium is a pig of a material to coat well. Although I dont know much about anodising but bearing in mind masts are anodised I am sure internally it is well up to the job?

 

[ganter]

Thanks for those replies.

Fair winds.

 

[MM5AHO]

Powdercoating is just paint applied in a solid form instead of a liquid. Its not some magic.
Like any paint, the quality of the coating is important, but equally (or more) importantly, the pretreatment system must be right.
Few paints (whether powder applied or liquid) adhere to aluminium without suitable pretreatment. Chromate is the best, but there are others.
If you get powdercoating on it, ask about the pretreatment system.
Abd like paints, there's different qualities of powder, and many different chemistries. Polyester or polyurethane better for marine applications, but even better in a 2 coat powder applied system with epoxy first then polyester on top, all over a chromate pretreatment.

For comparison, I powdercoated my roof hatch, been exposed to the sea spray now for 4 years, no sign of deterioration. (yet)

 

[Seajet]

Going back to my metal finishing days, aluminium is a pig of a material to coat well. Although I dont know much about anodising but bearing in mind masts are anodised I am sure internally it is well up to the job?

Anodising is a very different process to powder coating though - the latter chips very easily, as seen on motorcycle frames; while the interior of a yacht shouldn't be as rough on treatments, it's not the best coating I've come across.

 

[Halo]

I have a small stake in a metal finishing business. What you need to do is get the pats hard anodised. This process will put a tough layer of ally oxide on the outside of the parts. They will look grey or you can specify black. It's not expensive. You need to put any threads in first and ask the anodiser to mask them.

 

[dgadee]

I presume there are different forms of aluminium. I had to repair my wheel pedastal - cast. One firm said they couldn't do anything since aluminium would not take powder coating, but another firm said no problem they did it all thte time. Now been a year and no sign of any problems.

 

[Alpha22]

Anodising is the way to go..... my windows are anodised... still OK inside and out after 45 years.... OK, there is a little tiny bit of corrosion on the ends of the exterior frames..... I think they were cut after the anodisation process.

Anodisation is a chemical change to the surface of the aluminium, powder coat is simply a layer of melted on plastic..... no bonding to the aluminium at all.

 

[nigelmercier]

Get an etch primer, then paint. I recommend Rustoleum.