I do believe ALODINE provides an insulating surface. The best preparation of
aluminum for paint processes is a chromate surface. This is accomplished per
MIL-C-5541 (ANSI has a different specification number for thsi process). This
is a conductive surface treatment and normally yields the light yellow to
brownish color depending upon length the parts are subjected to the chemical
conversion process.
The process is usually done with a series of tanks used to clean, coat, and
rinse parts. There are 2 classes of coatings based upon the requirement for a
very low surface resistance (Class 1A) or a normal conductive surface (Class
3). Some chemical conversion can be performed in clear color and must be
specified.
There is a new process that does not use chromates that we are investigating at
work. Because of the heavy metal attributes of chromate we do NOT do this
process ourself, but send it out to be done. A non-chromate process would
allow us to do it in-house and save a lot of $$ and lessen use of chromates
(hopeful eliminate 99% of our chromate use requirements).
I do some painting of aluminum at home and usually get good results by ensuring
the surface is clean of any oils. I clean with alcohol and use several light
coatings of paint. Most I then bake in the oven at about 170F, let your wife
go away for the weekend, or she might get very upset at this happening in HER
oven. Often after this I will allow the part to relax in the New Mexico sun to
continue in a natural baking process. The paint hardens very nicely.
If I can find a shop that does powder coatng (and does it within hobby budget)
I will have all projects painted in this manner. Powder coat is probably the
best commercial coatings available.
I may have digressed a bit but hopefully the info will be helpful to the
readers. I am sure others have had success with other processes. I for one
would be interested in other results.
73 de Arne N7KA
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