I'm working on my RV-12 wing kit and have decided to alodine and prime/seal the interior parts. That's not what this thread is about, though
I did my first alodining last night and am a little concerned about the results. All of the pieces were Alclad, and I used the following prep procedure:
1) Debur and smooth edges.
2) Glove up
3) Wash in Dawn, then rinse in plain water
4) Etch in EkoEtch (same as Alumiprep), scrub off the Alclad with a Scotchbrite pad, and rinse in distilled water per directions.
5) Dip in alodine solution. Full immersion was used for 2-3 minutes with almost all of the pieces.
6) Rinse by immersing in clean water.
7) Hang up to dry overnight
I immediately noticed a huge variation in coloring of the metal upon removal from the rinse. When I checked on the pieces this morning, the variation (unsurprisingly) was unchanged. The metal ranges from silvery aluminum with a gold sheen all the way to a uniform brown. I also found that wiping the parts with a damp cloth results in some of the color transferring to the cloth (that is, the cloth gets stained and the color on the metal lightens).
I did the stub spar by painting the alodine solution on the piece rather than immersion. The color still showed variation, but not nearly as much as the dipped pieces. And there was much less excess to wipe off.
So, is this normal? Do I need to wipe down all of the pieces before I prime, since the excess may effect the bonding of the primer/sealer?
Or do I need to fix something? Should I actively wipe off the alodine in the rinse phase? Did I skip a step, such as wiping the pieces with paint thinner prior to the Dawn wash? Do I need to be more vigilant about removing all of the Alclad in the etch process?
I'm trying not to be neurotic about the build, but I'd hate to screw up the most internal pieces of the wings for all sorts of reasons. Folding wings = bad. Fixing wings spars and doublers after assembly = almost as bad.
I did my first alodining last night and am a little concerned about the results. All of the pieces were Alclad, and I used the following prep procedure:
1) Debur and smooth edges.
2) Glove up
3) Wash in Dawn, then rinse in plain water
4) Etch in EkoEtch (same as Alumiprep), scrub off the Alclad with a Scotchbrite pad, and rinse in distilled water per directions.
5) Dip in alodine solution. Full immersion was used for 2-3 minutes with almost all of the pieces.
6) Rinse by immersing in clean water.
7) Hang up to dry overnight
I immediately noticed a huge variation in coloring of the metal upon removal from the rinse. When I checked on the pieces this morning, the variation (unsurprisingly) was unchanged. The metal ranges from silvery aluminum with a gold sheen all the way to a uniform brown. I also found that wiping the parts with a damp cloth results in some of the color transferring to the cloth (that is, the cloth gets stained and the color on the metal lightens).
I did the stub spar by painting the alodine solution on the piece rather than immersion. The color still showed variation, but not nearly as much as the dipped pieces. And there was much less excess to wipe off.
So, is this normal? Do I need to wipe down all of the pieces before I prime, since the excess may effect the bonding of the primer/sealer?
Or do I need to fix something? Should I actively wipe off the alodine in the rinse phase? Did I skip a step, such as wiping the pieces with paint thinner prior to the Dawn wash? Do I need to be more vigilant about removing all of the Alclad in the etch process?
I'm trying not to be neurotic about the build, but I'd hate to screw up the most internal pieces of the wings for all sorts of reasons. Folding wings = bad. Fixing wings spars and doublers after assembly = almost as bad.