Alodining - By John Cox

Reference Materials:
Alodine Vs. Anodize
RV-10 Alodine (DeHaviland Dash 8)

<excerpted from the RV-10 Matronics List>
At the airlines, we always acid wash the aluminum with phosphoric acid
then copious amounts of deionized water before the Alodine application
process. I have attached passages which might apply to our RV-10

"Touch-up Alodine" is used with a handheld container much like a magic
marker to apply spot application.

You can disregard Section 3 - as the RV-10 is not yet fabricated using
any Titanium or associated alloys. Well maybe some scrap parts will be
fabricated on mine.

Our issue is, was and will remain the delaminating effects of Jet A and
Skydrol (phosphate ester based brake fluid) on the final topcoat.
Neither is a factor with the RV-10 using Avgas or H5606.

Using the correct primer for adhesion to the treated aluminum which is
also compatible with the final topcoat is critical. Changing
manufacturers is never done between primer and topcoat. I think it is
the secret formulas and special pricing that frightens us.

All Amphibians, all military and all commercials get Alodine. Cheaper
cost Spam cans skip the step cause the insidious damage is not obvious
till the product liability coverage lapses. Many kitbuilders skip this
important step (In my opinion) to save dollars. Just like using
automotive vs. aerospace hardware and electrical connectors. Risk /
Reward analysis.

Personally I would not purchase nor recommend any client buy another
builder's kitbuilt aircraft that was not alodined. Just one of many
corners cut on the road to perfection. Keep up the extra consideration
and effort.

John - KAUO