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Again with the fingerprints!

LettersFromFlyoverCountry

Well Known Member
(Reposted from the blog)

IMAG0073.jpg


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.
 
Try it with a rubber glove on the fingers? That should tell you if it is an interaction between your skin oils and the polish, or not.
 
Bob-

Couple of thoughts for your consideration:

1. I always wear rubber gloves whenever I detail/polish the plane (which is after every flight)
2. I dip my microfiber towel (the ones that Perfect Polish sells) into the Nuvite tub and then use it to dab the Nuvite onto the aluminum

All of the fingerprints I get are now from the airshows I fly at...while not perfect, I think she still looks pretty good
N411TW%20Polished%20Wing_zpsevrjdpxr.jpg

Good luck!

-Tim
 
I use vinyl gloves so it's no an interraction with skin oil.

I'll try the microfiber towel idea; that's a good one.

It's almost as if the polish dab is etching the aluminum; that's why I'm curious if there could be any chemical change in the product in the time that might lead to that.
 
Bob-

I had a jar of F7 that began to separate (oil from compound) after a very extended period of time, so I'm sure there's a chemical change occurring. That being said, do you see any visible separation in the jar of S your using (a thin oil on top of the white paste)? If so, did you try remixing the S before applying?

-Tim
 
I've seen evidence of the oil separation in an old jar of Grade S also. So far, I haven't found it acts differently than "normal" S grade. Given the cost of the stuff, I'm too cheap to throw out what's left !
 
Bob-

Couple of thoughts for your consideration:

1. I always wear rubber gloves whenever I detail/polish the plane (which is after every flight)
2. I dip my microfiber towel (the ones that Perfect Polish sells) into the Nuvite tub and then use it to dab the Nuvite onto the aluminum

All of the fingerprints I get are now from the airshows I fly at...while not perfect, I think she still looks pretty good
N411TW%20Polished%20Wing_zpsevrjdpxr.jpg

Good luck!

-Tim

yOWZA!!! That's some polish P0rn right there.

When you say you polish after every flight, what sort of degree of polishing are you doing?

I'm not sure I'm quite "there" yet. :eek:
 
Thanks Bob. "Patience" (the planes name :)) get's a thorough detailing after every flight which typically consists of:

1. Cleaning all painted surfaces (special attention to leading edges) with Meguiars
2. Cleaning the canopy with Novus
3. Cleaning all polished surfaces with an alcohol concoction I make (special attention to prop, spinner and leading edges) to remove any bugs, etc. If there's a surface imperfection I will hit it with Nuvite S and the orbital (I rotate detailed polishing of the various surfaces (port top wing, starboard top wing, bottom port wing...) on a monthly basis).

It's tough being a perfectionist with a polished plane ;)

Polished%20Airplane%20N411TW_zpsqit8ifnw.jpg
 
Pitfalls of Polish

I also use Nuvite S on my fully polished 7A. Last month, my son and I flew to a weekend flyin where the 'locals' had full access to the tarmac. No sooner did we arrive and several non aviation folks swarmed our plane and planted their sweaty imprints over the fuselage, wings, empennage, any everywhere that I had just polished.
Needless to say, we didn't stay long. But it was satisfying to see the enthusiasm and interest in our polished plane.

Jim Diehl 7A
Based at Lock Haven, Pa.
 
I have been polishing and learning the trade quite a bit over the last month or so. Getting nice results, but spending lots of time. I might have an idea of what is causing your fingerprints..

I bet it is like if you write "wash me" on a dirty car. The dirt can scratch the paint under your finger.. Maybe when you dab your finger on the surface with the abrasive polish on it, you are sliding it slightly and scratching the surface. Then the final grade polish isn't enough to cut through the scuff.

Anyway, just a thought.

Thx
 
I have been polishing and learning the trade quite a bit over the last month or so. Getting nice results, but spending lots of time. I might have an idea of what is causing your fingerprints..

I bet it is like if you write "wash me" on a dirty car. The dirt can scratch the paint under your finger.. Maybe when you dab your finger on the surface with the abrasive polish on it, you are sliding it slightly and scratching the surface. Then the final grade polish isn't enough to cut through the scuff.

Anyway, just a thought.

Thx

I think that's right. For the spring polishing -- underway now -- I'm dipping old fleece pieces (yeah, occasionally I'll actually wash those old ones) in the polish and use that to dab it onto the AL and it seems to work just fine, as someone predicted upthread.

And, yes, it does take time; but less so after you've polished and compounded a few times. Sometimes Cyclo and S alone is enough to bring life back to things.
 
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