what's on my prop?

[capz]

I wanted to get one more summer out of my props and have a shop recondition them next season. So I figured I'd clean and polish them myself. There's a thin, rough coating on them that's real tough to get off. I tried a few stainless steel cleaners and a Scotchbrite pad. I finally got down to bare metal by sanding lightly with my drill. I'd rather not go any further and risk warping the blades. I'd like to find the correct cleaner to use. I just don't know what the coating is. I attached a pic. Is it paint, corrosion, rust, growth?

 

[Henry Boyd]

I was thinking about doing the same to mine and noticed they were coated with something. It might be a clear coat to cut down the galvanic corrosion between the props and alu housing.

This might be worth a call to Mercury customer service.

Henry

 

[Riptide III]

If your talkingabout the dull greenish color, it looks like growth to me. None of my 4 stainless props have any type of coating on them. As far as you warping it by sanding, I doubt it. Ive TIG welded little nicks on the edges of the blade and not done damage to the pitch.
Phil

 

[H2ONUT]

yeah, looks like growth to me also. (mist it with water and see if it's slippery)

sanding won't hurt the prop at all.

 

[Hampton]

I had that on my props and I kept the boat out of the water. I think it has to do with heating them up in sand or cavitation. It comes off with steel wool. It's like a calcium deposit or something, judging from my old 250's props.

 

[geriksen]

its just funk
muriatic acid will clean it right off
dilute it with water and scrub with a brush

 

[capz]

Naval Jelly did the trick. You can find it at any hardware store. I globbed it on, took the dog for a walk, ate dinner, an hour later it all brushed right off with a Scotchbrite. Even the dog was impressed.
I think I'll get more to touch up some rust spots on the engine. If you try it be careful around painted areas. Be prepared to prime and repaint soon after using it.