Tuesday, September 29, 2015

Fingerprints



There's an old saying in the homebuilt airplane business. "The only reason to build an airplane is that you want to build an airplane." The same is true for people with polished airplanes, who have to constantly endure the admonishment that it's too much work. "The only reason to have a polished airplane is because you like polishing airplanes."

Big, expensive paint jobs are swell for those with big checkbooks. But park a painted airplane next to a polished one, and the polish attracts the eyeballs every time.

And that's the problem. Given enough exposure to polished aluminum, the defects soon become visible.

Thanks to the reflection of the fluorescent light in the photo above, you can see a couple of examples of something that is all over the plane. Fingerprints. But these are not prints from someone touching the plane. They're fingerprints from the application of Nuvite polish. As the instructions say, "dab" fingerprints of polish on the aluminum, smear with the wool bonnet on a drill or rotary machine (or cyclo machine). Voila!

Last winter, I noticed this happening. Very fine scratches would be put into the aluminum where the finger applied the polish, even if the polish was soon smeared around the AL. Even if the compounding (and cyclo'ing) took place.

At the time, my theory was that the aluminum was so cold, the polish was freezing in place and small amounts of ice scratched the surface.

But over the weekend, I polished a section of wing when it was about 80 degrees, and you can see the result, even though the area was subsequently polished with F7, Grade C, and Grade S polish and a new fleece blanket and then buffed with fresh fleece and flour.

Curiously, this started last year, two years after I first bought the polish. I tossed out a small can of F7, thinking that maybe it was the culprit. But an equally-old can of polish yielded the same results.

Is it possible that polish "goes bad" and causes this problem? We will continue to investigate the mystery.

In the meantime, when you look at my plane, leave your glasses at home.

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