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Re: Good polish
OK guys, I'll admit I don't know the FAA rules on prop polishing, but from a metallurgical or engineering perspective you should NOT polish off anodize. That is ANODIZE, not Alodine! Anodize is a plating process, alodine is a conversion coating process. If you remove Anodize you have removed an expensive and costly corrosion protection that the manufacturer wouldn't have put on the part if it wasn't made from a material that needed it (there are cosmetic reasons for anodize but it is pretty pricey compared with paint). There are lots of aluminum alloys and some are pretty corrosion resistant, some aren't. If you have an anodized prop it probably NEEDS the anodize (never seen one personally).
From a metallurgical and design perspective you could polish off alodine, but you have GOT to keep is polished from then on and the part will corrode pretty quick if there is a corrosive environment. Again, I DON'T know about what is legal for props. Mine is painted.
If I had already polished my prop and read this thread, I would be on the phone with the manufacturer first thing Monday and ask them what the next step is. The next step IS NOT to trash the prop! WORST case is you might have to send the prop back for an overhaul. When props are overhauled they would need to strip all coatings off to properly inspect anyway. Best case is you can keep polishing it or they will let you re-alodine and paint it yourself (you aren't going to be anodizing a prop in your garage). Maybe you can clear coat it if that is OK with the manufacturer.
Big thing is DON'T PANIC and do something dumb like trashing it! If you have to overhaul it, oh well, at least you have a new prop. You can't do anything to a heavy hunk of aluminum like a prop that will completely ruin it from a can or bottle you can buy at an auto parts store, at least not from ONE polishing.
Hank
OK guys, I'll admit I don't know the FAA rules on prop polishing, but from a metallurgical or engineering perspective you should NOT polish off anodize. That is ANODIZE, not Alodine! Anodize is a plating process, alodine is a conversion coating process. If you remove Anodize you have removed an expensive and costly corrosion protection that the manufacturer wouldn't have put on the part if it wasn't made from a material that needed it (there are cosmetic reasons for anodize but it is pretty pricey compared with paint). There are lots of aluminum alloys and some are pretty corrosion resistant, some aren't. If you have an anodized prop it probably NEEDS the anodize (never seen one personally).
From a metallurgical and design perspective you could polish off alodine, but you have GOT to keep is polished from then on and the part will corrode pretty quick if there is a corrosive environment. Again, I DON'T know about what is legal for props. Mine is painted.
If I had already polished my prop and read this thread, I would be on the phone with the manufacturer first thing Monday and ask them what the next step is. The next step IS NOT to trash the prop! WORST case is you might have to send the prop back for an overhaul. When props are overhauled they would need to strip all coatings off to properly inspect anyway. Best case is you can keep polishing it or they will let you re-alodine and paint it yourself (you aren't going to be anodizing a prop in your garage). Maybe you can clear coat it if that is OK with the manufacturer.
Big thing is DON'T PANIC and do something dumb like trashing it! If you have to overhaul it, oh well, at least you have a new prop. You can't do anything to a heavy hunk of aluminum like a prop that will completely ruin it from a can or bottle you can buy at an auto parts store, at least not from ONE polishing.
Hank
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