These are my rotors that are 15 years old, but never been used, not even assembled onto the hub bar.... they have a splotchy look to them from sitting.... no pitting, no bad oxidation on them, when I washed the dust and gunk off them, there was remnants of the wax on them from manufacture.... there is a few little scratches, well, hardly scratches.... but just from storage. The guy I got them off got them about 15 year ago, they stayed in the cardboard until that fell apart, then have just sat in a shed, gathering dust.

I have washed off the dust and am about to try and shine them up a bit.... what technique do you guys use? I am going to get some 1200 or better wet and dry sandpaper and give them a light rub with that with soapy water, then hit them with some cutting compound, then car polish.... see how that goes

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Are those white spots corrosion ? The white powdery stuff around the rivets look like corrosion too. Exterior corrosion is one thing , the interior corrosion could be even worse , are those bonded and riveted blades ? I would worry about the bond , if the aluminum was not chemically treated corrosion would be there before they were even assembled

Every hour of every day , and every degree of temperature change , will have moved air and humidity inside and out of those blades for 15 years just sitting on the shelf , the metal would have expanded and contracted as well , thermodynamics never rests.

If those were my blades I would use a bore scope to at least take a peek inside as far as you can (looking for corrosion) , white powdery stuff ,

And if I was to fly them I would get an AMERICAN QUARTER from FRANK ROBINSON and do a tap test every hour

There are some days I love Frank , but I will only tell you MadMuz , I dont want farmer titanium to get jealous

Good luck with the blades , if Hillberg chimes in , listen to his advice , he knows best.

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To answer your first question I would do it the lazy way (trying to get a shine) (trying to clean the blades)

I would use Purple ficking Polish

And if the corrosion pits are still there , MAYBE 1200 grit wet sanded carefully by hand , some polishing with rubbing compound SLOW AND COOL with a buffer ... do not overheat the aluminum , either with a buffer or sander , then purple ficking polish again

Mostly I would want to be reassured they would not dis-bond , I would care less about the shine,

Thanks Arnie, yes, they are bonded and riveted, I had a go at one with 1000 grit, then 1500 grit with soapy water and they clean up nicely. The spots are not corrosion they are just fly spots, mouse crap and dark marks, I could sand and bugger around with them and try and make them look perfect, but I am just going to get them smooth and not worry too much about looks.... The rivets are all tight and fine..... there was no white powder corrosion, just years of dust mixed in with the wax. They will be thoroughly examined (microscopicly) once I start using them. The guy who manufactured them had some bad glue near the end of his run, I put some pics in somewhere where a set delaminated in flight, but those were glue only (no rivets) which is why they have rivets now. ASRA requires this brand of rotors to have extra rivets placed between the existing rivets which are like 5" apart, which I will do. I wont be doing any machine polishing or sanding.... they will just be made look as best they can by hand. I was going to take a pic of the top of the one I have started on, but my windshield dude came and interrupted me and it got dark

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Sounds good Murray , I love sanding and polishing aluminum , done thousands of hours of it , (non aviation)

Bees Wax on sandpaper is the only thing that keeps it from plugging up , has to be real beeswax , industrial suppliers have it , comes like a big crayon

You might think I was lonely out the back sanding the rotors.... I wasn't tho.... I had help

They didn't give me any lip.... weren't much help either.... they just supervised

FJ, that was the little joey in the pouch when you were here

I can see the corrosion at the bond line. 1- tap test and 2- add an extra rivet between the ones you have now.

x-ray would be nice check for exfoliation of the spar or pull a tip cap off and check with bore scope.


inergranular is more dangerous. surface not so much

Agreed!!! 100 percent...

Thanks guys, but what you see as white, is just where the metal hasn't been sanded, it is just dull, which appears white or 'frosty' in the pics, but it isnt. I don't know what is wrong with my camera, have to get another one.... it wont be a Nikon coolpics, that's for sure

There is no corrosion. I have tapped a coin along the bonded areas and there is no difference in sound and the extra rivets will remove any doubt

Stan swears by "Purple-polish" if you can get it in your neck of the woods.
The Helicycle rotor-blades looked pristine, like mirrors.

K.

Yeah, Scott mentioned purple polish the other day, I said we don't have it here in

So I went down to the car parts store and here is a rack of purple polish

Weird looking stuff.... it had separated out to purple and pink....obviously needs shaking....lol

I might give some a try

If there is one thing I understand...its how to get a deep mirror finish out of aluminum. My Helicycle blades were like telescope mirrors...not kidding. Purple polish is part of it....and yes...you can just dump it on and start buffing...and you will have a shiny surface....but not a deep mirror surface. There is a difference that only you can detect in person.

It takes progressively sanding to finer and finer grit....then use Purple polish.

Been there and I know what I am talking about.

Thanks Stan, I will give it a go.... I am not going to try to make these ones too shiny, just as long as they are smooth.... As long as they work

Oh....and one MAJOR point I omitted.....the finer you get the aluminum surface....the easier it is to keep shiny.

I got all my information out of an article in KitPlanes years ago. A guy had an all aluminum polished airplane....hundreds of square feet....it was beautiful....and that part about it being much easier to maintain the more elbow grease you use in prepping the surface..stuck in my head.....and my experience showed me it was true.

I have one done.... came up great with 1000, then 1500 wet and dry then purple polish.... not show quality, but way above acceptable

As we Aussies say.... "she'll be right mate"

Edit: before and after