Wind generator paint falling off

[Guest]

Have an aerogen wind genny and the paint or coating is coming off the alloy housing.What is the best to recoat it with? 1, Alloy antifoul? 2,etch primer then paint? 3,leave it, Interested in all Ideas.

[wheels 543]

The first thing is you need to remove the old stuff back to the bare Aluminium. Then an etch primer and top coat. I did the same to my wind gen and used Watyls Etch Primer and then Rustoleum white top coat. Seems to have worked well, but time will tell.

[idlerboat 116]

.. as much as paint systems is not one of my favourite subjects at the moment, I agree with wheels.

I would like to add that I have seen the same problem many times with the airX range of gennys.

They are a cast ally body. The first sign is localised and spreading blisters (sounds like a medical condition) when scraped off there is both pitting and a white powder ...and when scraped a dark colour to the pitted surface.

A possibility that may make the condition worse is the direct connection to a stainless steel stub pole or similar.

Most of these gennys have an anti vibration bush or sleave that also acts as an electrical isolation insulator.

The idea being that positive, negative, and ground currents only travel through the wiring and not between the geny body and supporting structure. This can happen when the spin off from old brush dust collects and makes a contact with the housing.

(AirX lists this as a major problem (fail) of older units.)

The direct connection of ally to stainless is problematic regardless, without some kind of mitagation.

 

cheers

[wheels 543]

I think the issue is really just a poor powder coating to begin with and even a really good powder coating can have adhesion issues to Aluminium. They don't use any form of etch priming in powder coating, so the surface is not treated and then adhered to to stop further oxidation. After a long time, the surface gets just enough oxygen to create the oxide layer and the powder coating starts to let go. Then add a little moisture underneath and you get the white oxide forming that causes the blisters.

The same can happen with a painted surface if an etch primer has not been used. The surface must be etched and sealed wet to stop that oxide layer from forming. That's the way I see it anyway.

[Steve Pope 243]

A not so easy solution that I used with a Lofrans windlass that had very bad oxidation issues was to strip it and get the body anodised, I didn't bother painting it afterwards, worked a treat.

[Guest]

Guy with a yacht next to mine has a powder coating business and he tells me they have some new treatments that are "better than Galvanising" so may be a good idea to ring one and ask.

[tuffyluffy 76]

I’ve got an alloy yacht, therefore alloy corrosion is something I keep an eye on pretty closely.

 

As they others have mentioned, the alloy blades should be isolated from most other metals, if not, your ongoing maintenance will be constant.

 

If you’re sure the blades are isolated, id strip the paint back to bare alloy, then with an electric wire brush, give the blades a thorough ‘liven up’ then coat with a decent etch primer ASAP (preferably same day to minimize oxidation), then topcoat. There is a special 3 pot (yes 3) that Altex supply, but for a small amount its probably overkill.

 

Also, if you are reassembling the bits afterwards, use lots of lanolin, or something similar to reduce the metal-to-metal conductivity.

 

You'll know within 12 months if youve got it right or not

[Guest]

Thanks for all your help , Striped it,Cleaned it, Etched it and painted it,Will keep an eye on it and see how it looks ina year or so. Cheers :