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Just because it looks bare doesn't mean it's unfinished. If I specified sheet aluminum for Type II Class 3 chemical conversion per MIL-DTL-5541, any materials

Just because it looks bare doesn't mean it's unfinished. If I specified sheet aluminum for Type II Class 3 chemical conversion per MIL-DTL-5541, any materials QC professional would be hard pressed to visually determine that anything was actually done to the material. To be sure, no, MIL-DTL-5541 isn't an uncommon spec constrained to military applications.

0_____0 7y ago
any idea what they use on aircraft skins?
- metaphor 7y ago
  That's not an application you can generalize. Literally everything is dependent on requirements.
hinkley 7y ago
I know I've noticed on airplanes before that while some of the wing is aluminum colored, some areas in particular are painted a vaguely aluminum-colored shade of grey. And I think the... it seems they're called Krueger flaps? Those are often painted aren't they? And those I'd think you'd definitely want to de-ice.
- handedness 7y ago
  On an aircraft that has a mixture of polished and painted surfaces, the painted surfaces often aren't bare aluminum. Often that's the wing root fairings, winglets, nacelles, radar cones, vertical stabilizer, and so on.
  - hinkley 7y ago
    I don’t think I was meant to get a giggle out of this. Can you explain using other words? Of course a painted surface isn’t bare. It’s got paint on it. Did you mean it’s not aluminum? Or a different grade?
    - handedness 7y ago
      Thanks, I laughed at it myself, in hindsight. I should have stipulated "underneath" and likely appended an "if you follow...". Yes, well, they may either be materials that have other surface textures/coatings/treatments/finishes that aren't conducive to polishing, or they may be other metals, or non-metallic composites (can't put aluminum over a radar, for example), and so on. TL;DR: The painted surfaces are generally instances in which polished aluminum won't really work, for a variety of reasons.
handedness 7y ago
In addition to that, behind every beautiful, polished aluminum aircraft is a crew that is washing, cleaning, and polishing it regularly. Polished surfaces are higher maintenance than painted ones, generally speaking, and by quite a bit. Polished aluminum is not low maintenance by any stretch.

0_____0 7y ago

any idea what they use on aircraft skins?

metaphor 7y ago
That's not an application you can generalize. Literally everything is dependent on requirements.

hinkley 7y ago

I know I've noticed on airplanes before that while some of the wing is aluminum colored, some areas in particular are painted a vaguely aluminum-colored shade of grey. And I think the... it seems they're called Krueger flaps? Those are often painted aren't they? And those I'd think you'd definitely want to de-ice.

handedness 7y ago
On an aircraft that has a mixture of polished and painted surfaces, the painted surfaces often aren't bare aluminum. Often that's the wing root fairings, winglets, nacelles, radar cones, vertical stabilizer, and so on.
- hinkley 7y ago
  I don’t think I was meant to get a giggle out of this. Can you explain using other words? Of course a painted surface isn’t bare. It’s got paint on it. Did you mean it’s not aluminum? Or a different grade?
  - handedness 7y ago
    Thanks, I laughed at it myself, in hindsight. I should have stipulated "underneath" and likely appended an "if you follow...". Yes, well, they may either be materials that have other surface textures/coatings/treatments/finishes that aren't conducive to polishing, or they may be other metals, or non-metallic composites (can't put aluminum over a radar, for example), and so on. TL;DR: The painted surfaces are generally instances in which polished aluminum won't really work, for a variety of reasons.

handedness 7y ago

In addition to that, behind every beautiful, polished aluminum aircraft is a crew that is washing, cleaning, and polishing it regularly. Polished surfaces are higher maintenance than painted ones, generally speaking, and by quite a bit. Polished aluminum is not low maintenance by any stretch.