Harry Roussard:
I am trying to find a good way to polish my spinner and it’s a BEAR. What is a good process? (Spinner polishing; polished spinner; polish spinner; polish my spinner)
Editor:
-1- Take the spinner off the plane. Cut a piece of 2×4 with the ends rounded and beveled (using a coping saw or similar), so that it fits flush inside the back of the spinner (flat side across the back of the spinner). Put two long-ish sheetmetal screws through two existing holes that overlap the ends of the 2×4, on each end of it. Something like bugle-head drywall screws work well, but don’t crimp in the spinner holes. You can angle the screws toward each other if necessary, to get a good “bite”. You don’t want the spinner moving or coming off. while you are working on it.
-2- Clamp the 2×4 in the jaws of a vise, to rigidly hold the spinner while you work on it.
-3- Buy three large-ish cotton buffs that you can chuck in a drill; or three bonnets for a small buffer. A big buffer is too hard to work with. You need something maneuverable. Denser buffs will cut faster, but looser buffs are better for the final polishing compound.
-4- Go to Sears (or wherever) and get two grades of aluminum polishing compound. They usually come in sticks or bars, not in tubes. You want a fast-cutting grade, and a medium-cutting grade.
Also buy a tube of the German polish called Simichrome, if you can find it (online or at auto parts stores). It is relatively expensive for the quantity, but provides the best final “mechanical polish”. Otherwise you
can use whatever final polish you plan to use for maintenance. I’ve been
using Metal Gleam lately (last 6 years), but everyone seems to have a favorite. I advise against one popular product called Nevr-Dull. It is easy to use, as the compound is carried in cotton wadding that you just pull out of the can and use as-is. It also provides a decent quick shine.
Unfortunately, it quickly loses its “depth”, and starts looking gray. I have been told that the stuff uses some acid in the mix in order to more quickly create a shine, but the result is that the shine doesn’t hold up. I don’t really know for certain “why”, but the shine fades fast with Nevr-Dull.
-5- Put the fast-cut compound on the first buff, and go to town. Try to keep moving and varying position. To the extent you can, move the buff fore and aft, but some side motion is almost unavoidable. Make DAMN sure no metal parts hit the spinner; the resulting ding won’t be removable by you.
After the spinner has a consistent polish and color all over, carefully clean off all the fast-cut mix. Put the medium mix on the next clean buff, and repeat. Then repeat with the third buff, using the Simichrome. Try to
do all the Simichrome work fore-and-aft. Wrap up with a hand-buffing with
a clean cotton towel. Make certain that you store each buff in its own bag; don’t let any compound cross-contamination occur.
After you have gone through this thorough process one time, you won’t have to repeat it for years. Unless, of course, you fail to maintain it with a
periodic hand polishing (using the Metal Gleam or Simichrome). The
periodic hand-polishing only takes maybe fifteen minutes, working fore-and-aft. Just slip a towel behind the spinner to keep the black film off the plane, and try to avoid the prop blades.
The worst contaminant is dried water. It can be very hard to get water spots out of polished aluminum, once they have fully formed. If the plane is outside, they are hard to prevent. If it is hangared, buff the spinner dry any time you hangar the plane wet. I usually dry off the whole plane, as that’s the only time it gets wet. All my other aircraft cleaning is hand-washing using spray-on product; no buckets, running water, or hoses.
Please note. Factory-painted spinners and some shop-painted spinners often had an acid-etch type of treatment, to aid the paint adhesion. Any such artificially-roughened spinners will require much more polishing during the initial stage of work. Also note that prop shops strongly advise against polished props (as opposed to polished spinners), on planes that actually get used outside a museum or infrequent air show appearance.