Polish aluminum spinners: Bringing out the shine is easy

Model Airplane News, Sep 2003 by Bell, Rick

Like many modelers, I want to have a sharp-looking plane that stands out on the flightline. One detail that can really grab attention is a highly polished metal spinner that gleams and glints on a bright sunny day. Most metal spinners are made of turned aluminum that isn't shiny. Although they have a nice shape, these spinners just don't have the chrome-plated look that could set them apart from the crowd.

Polishing an aluminum spinner to bring out that shine isn't difficult. In fact, it's pretty easy and requires just a few, easy-to-find supplies. The most important item needed for this project is elbow grease-something that modelers have a lot of! For this article, I used a Tru-Turn 2 1/2-inch-diameter aluminum spinner that saw a lot of flying last year. Why not follow along and learn how to add a touch of class to your airborne pride and joy?

1 Although there are various ways to polish metal, the best way to polish turned aluminum is to sand the spinner with successively finer grits of wet-and-dry sandpaper used wet. You'll need sheets of 240-, 400-, 600- and 1,000-grit sandpaper; you can find them at any hardware store. To bring out the shine, you'll need a cream-based polishing compound and a Dremel Moto-Tool with a large, felt polishing wheel. I use Blue Magic metal polish; it's available at auto-parts stores. Just about any metal polish will do, so you don't need to buy an expensive brand; the cheap stuff works just fine.

One note of caution here: don't mount the spinner in a lathe, a drill press, or a hand drill to rotate the spinner. Those power tools would turn the spinner so fast that you could damage it or injure yourself.

2 Fasten the backplate to the spinner. Insert a long bolt through the spinner's nose and securely tighten a nut and washer to the rear of the backplate. It's best to grind down the bolt's head (if necessary) so it fits completely inside the recess. If you use an extra-long bolt, you'll have a convenient handle to hold the spinner.

3 Start by sanding with the 240-grit sandpaper used wet. If you look closely at the spinner, you should see tiny radial grooves that encircle the spinner. The cutting tool that machines the spinner to shape creates these grooves. The grooves are similar to those on an old 33rpm record. The best way to remove them is to sand at 90 degrees across them-not parallel to them.

With a stroking motion and moderate pressure, manually sand the spinner from its nose to the backplate. Make sure that the sandpaper is wet at all times, or it will "load up" with aluminum powder that will scratch the spinner. Your goal in this step is to smooth out the machining tool's marks.

As you sand, the spinner will develop a satin finish; uneven areas that need further sanding and sections that you may have missed will be obvious. When you've sanded out all of the tool marks, it's time to switch to finer, 400-grit sandpaper.

4 Sand the spinner as before, but this time, at 90 degrees to the previous direction; in other words, sand the circumference. Every time you move up to a finer-grit sandpaper, you must change the sanding direction by 90 degrees. As before, be sure to keep the sandpaper wet, and sand the spinner until all of the previous sanding marks are gone and the spinner takes on a nice burnished look.

Now, change to 600-grit paper and alternate the sanding direction; again, sand it until the previous marks have been smoothed out. The spinner is starting to look pretty good, but let's take the sanding one step further.

5 This last sanding with 1,000-grit sandpaper really smoothes the metal, and it will begin to shine. Take your time to thoroughly sand the spinner to remove any remaining scratches. The better job you do with the sandpaper, the easier it will be to polish the spinner in the next step. You'll know you can move to the polishing step when it has a satiny look and feels very smooth.

6 This is where the elbow grease you applied in the past few steps pays off. Use the Moto-Tool and a felt polishing wheel to apply the metal-polish to a small area of the spinner. Use the tool at its medium speed (if the speed is too high, you'll "burn" the polish) with moderate pressure. Polish the metal until it turns black; as it does, the polishing cream will start to disappear, and the metal will look like chrome. Polish the entire spinner. When you polish near the prop cutouts and at the backplate edges, be sure to run the polishing wheel parallel to the edges; if you don't, the wheel can grab the edges and dislodge the spinner from your grip.

When you are satisfied with the spinner's shine, use a clean cloth and glass cleaner to remove any polish residue. You'll be amazed at the results!

If you don't have a Dremel tool, you can polish the spinner by hand. It will take longer, but the results will be much the same. It takes me about 2 hours to polish a spinner of this size; larger spinners will take more time.

That's all there is to it! A little time and elbow grease will yield a spinner that looks as if it has been chrome-plated. But you don't need to tell your flying buddies that!