At 21:24 02/01/97 GMT, you wrote:
>Duncan McFadyean mentioned using Alodine instead of anodising the alloy
>parts. I have already anodised most of my parts, but I am interested in the
>possibility of using Alodine on the remaining few. Any idea of where it can
>be obtained and how much.
>
>Thanks, David Watts.
Alodyne, Alumiprep (the pre-alodyne acid cleaner -essential) and zinc
chromate paint in various forms (spray cans, epoxy 2-packs) are available
---From aircraft spruce.
The standard aircraft finishing rationale is as follows:
Alodyne provides a similar surface to anodising (it's chemical anodising, if
you like) -it's hard, corrosion resistant (it's inert, itself) and paint
bonds to it far better than aluminium alloys.
Zinc chromate provides "active" corrosion prevention -as well as acting as
an undercoat. Epoxy is best because it adheres extremely well, but makes for
a poor finishing coat -it goes dull and dusty in time.
Linear polyurathanes (2-pack) of the correct type provided an excellent long
lasting, damage resistant finishing coats. But -it is difficult to repair
seamlessly.
Personally, I won't use etch primer on critical parts.
All the best,
Miles
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