Prop spinner chromed instead of painted?

It needs polishing when you are taking up a lady passenger… not before

Peter wrote:

I don’t think hot dip galvanising would work on aluminium.

I was not proposing that. I was just making an analogy to known failure mechanisms.

Polishing a spinner is easy, start the engine and apply polish :-) Just need to be a little bit careful with the propeller, otherwise you might end up with blood everywhere and having to do lots of cleaning.

I was about to make a bad joke about the position of your 185’s nose up high in the air and perhaps having to polish while on floats, but you can picture the result was a bit too disgusting for this otherwise polite venue, so I’ll refrain…

I started polishing my spinner this weekend. It used to be painted, but was stripped at least 10 years ago. It still bears the scars from this, so has never been polished.

I started with 1000 grit wet-and-dry sandpaper, then quickly worked down to 320 grit to have any effect. I got fed up doing this by hand, so once I finished one side, I did the other with the sanding attachment on my cordless drill. Even with very gentle pressure, it still ripped into the aluminium, and I was scared I’d taken off too much. Working back up through the sandpaper grades (320-400-600-800-1000-1200-1500-2000-2500-3000) by hand, the two sides were uniform again. This created a lot of dust, which was ok working outside in the wind, but would need a dust mask otherwise. It’s very fine, so disposable gloves were a must also.

Next step was to start polishing. I’d bought a set of buffing drill attachments, and a pot of Mothers mag and aluminium polish. Looking at the list of ingredients, it’s an abrasive (‘alumina’) held in suspension in a paste (various waxes and oils) with cleaning agents (alcohols, acids, and other chemicals). To stop it damaging the paintwork, I kept the aircraft cover on, and hung an old pair of curtains on the propeller. The first section was a miracle: it went to a mirror finish in seconds. However, the cotton buffing pad very quickly got clogged with a black mix of aluminium and polish residue, and the rest required more pressure and took a lot longer. Once the paste starts to dry, you polish it off by hand with a microfibre cloth and reapply the cleaner as necessary. I’d brought a nail brush to clean the buffing pad, but it only had limited effect. I did one half of the spinner to about 90%, then ran out of time. There are still some speckles in the polished section, so I should have taken more off at the coarse sanding stage. It’s also hard to sand and polish around the screws.

The sanding took approx. 2½ hours; this could have been about 30 minutes quicker if I’d done both sides with the drill attachment. A sanding wheel would probably have been faster still, but maybe harder to control?

The polishing took 1½ hours to get one half of the spinner to ‘almost there’. I would estimate another 2 hours + to finish the whole spinner. The drill speed was too low for buffing, and in hindsight I should have got a cordless buffer like people use for cars.

Before:

Coarse sand by hand:

Sanded with the drill:

Finished with 3000 grit by hand:

The first section polished. Seeing a reflected cloud made the effort worthwhile.

Almost done. The dark parts which look like shadows need more work.

Speckles and screws need more work:

Painting needs good preparation – probably hours

Primer, base, UV lacquer. Search for MAPAERO for example threads. Then you get different paints. The best system is 2K which like a lot of good stuff is super toxic.