Hmm aluminum etching is a no brainer.   What the heck is a conversion
    coating?  I thought it might be a neutralizer.  Sounds like I am wrong.
    Perhaps a chemical reaction with the aluminum to create a coating onto
    which the epoxy could stick to? ?

Dupont 226S conversion coating it is an alodine. $50.00 a gallon goes on
after the $50.00 a gallon acid etching and must go on emmidiately. I
have it in gallons if you cannot find it in Japan. You will only need a
very small amount. I can put some in a small container for you.

Dan

--

Dan

That would be extremely kind of you.  I of course would appreicate you
sending a small plastic bottle this way but how to do it?  Is the Dupont
226S a hazazourous material? Acid obviously is but I can pick that up
locally.

There is an aluminum electroplating company in town.  I wonder if they
would know about the alodine converison coating.  I understand it is a
brush on liquid that can seal off the corrosion.  The sanding or etching
basically gives the surface a profile that the epoxy can key to.

Doug in Japan.

Doug goto your local yacht store and just buy the conversion kit :)
Just kidding. I know there is no local Yacht store in your town as you live in
the mountains. You might have to go to Tokyo. What you want is a preparation kit for bonding epoxy to aluminum.

Here are some more pictures showing what happens if you don't get it
right. I assume you have the Devcon already. I also assume you cannot
get JB Weld in Japan.

Here is a test device that I made to test JB Weld. I put it in the freezer
for a week or two and then boiled it. It is now a couple of years old
and still holding pressure. Done right JB weld is good to 3000 PSI.
The force on these end caps at 30 psi is about 100 pounds each.

Paul Lamar