Tips on polishing?

Django · **Posted:** Thu Aug 20, 2009 10:01 pm

I'm trying to polish a C-47 cowling and holy crap, is it tough to do! I spend a couple hours and I'm nowhere near where I want to be. I tried using my angle grinder with one of the plastic grit wheels and that took it from flat aluminum to sorta shiny. Then I tried a finer flap wheel to even out the swirls. Then tried polishing. It didn't do crap!

So next I tried a 120 grit wheel. This gave me heavy swirls and sparks to boot. Then back with the plastic grit wheel, finer wheel and then polish. Definitely better, but maybe only 50% of where I want to be. And the swirl marks cut too deep in spots as well.

I've polished my fair share of aluminum on hot rods, but never on aircraft aluminum and I'm surprised at how much harder it is to do.

Any suggestions to get to this point?

RMB · **Posted:** Thu Aug 20, 2009 11:29 pm

http://www.perfectpolish.com/

I didnt just pull this out of GOOGLE. I have done this and the results are spectacular. It is alot of hard work though.

bdk · **Joined:** Sun May 02, 2004 1:16 am **Posts:** 11324

What is the final grit of paper you are using? 1000? 1500? Are you using a DA sander?

JMHO, if you are going from a Scotchbrite wheel to polish you'll never get there!

Second Air Force · **Posted:** Fri Aug 21, 2009 12:42 am

Django,

When you get a system down pat I've got a Fortress for you to practice on! :shock:

Yeah, it takes some elbow grease, doesn't it! I have a hard time just polishing the spinner on our flivver.

Scott

Django · **Posted:** Fri Aug 21, 2009 9:40 am

I bet you do Scott! :lol:

I have an orbital, but it wasn't doing that much. I used 120. Maybe I need to hit it with the grinder and then the orbital. The panel has this ridges all over it. Kind like someone dribbled paint onto the surface, only it's all part of the aluminum. You can even feel some edges in places with your fingernail.

That polish looks interesting. Kinda pricey though. $95 for the sample kit!

CrewDawg · **Posted:** Fri Aug 21, 2009 11:53 am

You beat me to it Scott!!! :lol:

sdennison · **Posted:** Fri Aug 21, 2009 1:00 pm

Django wrote:

I bet you do Scott! :lol:

I have an orbital, but it wasn't doing that much. I used 120. Maybe I need to hit it with the grinder and then the orbital. The panel has this ridges all over it. Kind like someone dribbled paint onto the surface, only it's all part of the aluminum. You can even feel some edges in places with your fingernail.

That polish looks interesting. Kinda pricey though. $95 for the sample kit!

Have a pic of the piece? You need to start "coarse" and move to finer & finer, then polishing compounds. "Grinder" scares me. :shock:

Remember, aluminum is soft and once removed...gone.

I have used 240, 320, 600, 1200 the red ruge on a buffing wheel in a horizontal buffer, then Mother's and my own elbow grease.

Always thought "Elbow Grease" woudl be a great name for a polish. :wink:

hawkeyepoole · **Posted:** Sun Aug 23, 2009 12:03 am

I've polished a lot of metal, and a lot of aluminum. If the surface you're polishing isn't pitted or badly damaged, then something like Mother's on a DA and a lot of patience is the best thing. The ONLY time I would take ANY sandpaper type material to aluminum is if it's damaged with corosion or badly scratched from an 'event'.

I have a $200 D/A sander that i put a bonnet on, and use automotive polishing compounds on a nappy cloth bonnett and use a different bonnett with the Mother's type of polish. It's elbow grease and time. I'm a car guy, and not certified or even experienced with aircraft mechanics, but what scares me about using abrasives like 200grit on the aluminum is how thin the metal is to begin with. When I'm polishing an automotive valve cover, I have .5 inches of material to start with. When you're grinding on sheet metal from an airplane you're starting with, what, .06 maybe?

At the Auto Paint store you can find 3M brand polishes that are fine to superfine that can remove minor imperfections without losing metal.

I have in my hand a quart of 3m "Perfect-It II" Rubbing Compound. This is neat stuff, because as you use it the abrasive degrades and eventually turns to 'mud'. this would be safe to experiment on your aluminum with because it's designed for auto paint, which is much softer.

Hope this helps and isn't just me rambling.

Rossco · **Posted:** Sun Aug 23, 2009 6:35 pm

An orbital sander with a lambswool polishing pad is the way I did my ex bosses replica P51.Took about a week and ended up dirtier than a $10 hooker each day.

Not that I know these things.. :shock:

Elbow grease and hard work is the only way to do it.Stay away from anything that removes metal or leaves scratches.Have you tried Autosol or Car Mag wheel cleaner?You will need lots of it.

bdk · **Joined:** Sun May 02, 2004 1:16 am **Posts:** 11324

Just like any type of polishing, it is a matter of turning big scratches into smaller ones. Polish alone will not remove big scratches. Old beat up parts will require considerable sanding which does remove material. Only the manufacturer or maintenance manuals can tell you how much material is safe to remove.

ZRX61 · **Joined:** Tue Jun 14, 2005 10:16 am **Posts:** 2308

sdennison wrote:

Always thought "Elbow Grease" woudl be a great name for a polish. :wink:

Do NOT! google it..... :shock:

sdennison · **Posted:** Fri Aug 28, 2009 9:57 am

That is NOT what I had in mind. :evil:

Django · **Posted:** Wed Sep 09, 2009 8:10 am

Here's a pic. It's kinda hard to see, but this thing looks like galvanized sheet metal in appearance. There are some organically shaped raised areas too, like it had corrosion maybe? Are all panels like this when you try to polish them?

quicksilvermustang · **Posted:** Wed Sep 23, 2009 10:05 pm

You have a bigger problem then using a wheel or a strong grit, that aluminum has ALCLAD on it and it DOESN"t polish worth a darn. Trust me, having a majority polished P-51 and working on it 2 hours a day 7 days a week I'm here to tell you that the alclad in the part (when it was put on) went on and interlocked, for the lack of words, with the metal. Your best bet is a cloth polishing wheel with Nuvite C grit, use that till the product dissappears then hit it with whatever you are using as a final polish.

valdez25 · **Posted:** Thu Sep 24, 2009 12:37 am

I'm polishing my T-6 for the 1st time. The plane was surplused in '55, and spent '55 to '70 inside at a votech school. Then it sat outside at Chino, unpainted from 1970 to about '93 when it was painted. The cowlings and fairings were scratched pretty badly at the votech school. I bought the entire Nuvite product line from Perfect Polish and had fair results, but it was REALLY EXPENSIVE!!!! $49.00 per pound, and it wasn't aggressive enough to "soften" the scratches. I bought some Rolite Pre-Polish at Oshkosh, and have had very good results on scratched, old metal. I haven't gotten to the finer grits yet to finish up the job, but for older stuff, Rolite is the best I've found. I talked to Mike VadBonCoeur from Midwest Aero Restorations, and he said he starts out on the new skins on his Mustangs with Rolite, then moves to Nuvite for final stages. Here's a link to the Rolite product I used http://www.topoftheline.com/rolprep.html It's less than 1/2 the price of Nuvite, and will give you the results you want. (Unfortunately, it'll never look as good as the new metal on Scooter's Mustang!)

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