Corrosion/coating on props question

[stormyj]

Hey all,
Im used to aluminum props, but now have a Searay with stainless props on it. Duo props on twin mercs B3s. My question is, normally I would take my aluminum prop off, clean the shaft, relube, clean up the prop and repaint it. These new props have no paint, but have a corrosion on them. Just a thin film of dried gunk. I started cleaning them with a wire brush/fine grit sandpaper, then started wondering it that is what I should really be doing, hence this post. Do I even need to. I have seen way worse props. Here are the pics. Let me know what you think. Thanks.

 

[Scott Danforth]

looks like barnacle growth and other things.

Hey @tpenfield can you post a link to your prop painting thread

 

[stormyj]

looks like barnacle growth and other things.

Hey @tpenfield can you post a link to your prop painting thread

I got all the barnacles off and most of the other gunk. My querstion is about the thin film of dried stuff. I think it is a layer of dried algae or something. You wouldnt paint stainless props would you? Im not saying someone would. LOL I just think a nice polished prop would run better in water.

 

[Scott Danforth]

I got all the barnacles off and most of the other gunk. My querstion is about the thin film of dried stuff. I think it is a layer of dried algae or something. You wouldnt paint stainless props would you? Im not saying someone would. LOL I just think a nice polished prop would run better in water.

yes, on a moored boat, I would paint the props with anti-fouling paint.

stainless props used to come with paint, then because people want bling factor companies started not painting them. cheaper to manufacture and now they can charge more

 

[Grub54891]

I've seen a few props from saltwater use that had a rubber spray coating of sorts on them. Don't know what it was though. Stainless *shouldn't* need a coating?

 

[stormyj]

I don't know if it was paint or growth. But some muriatic acid/water cleaned them up nicely.
Ill monitor them and see how they do. It looks like someone might have painted them a long time ago and it was just wearing off. Barnacles came off easy. Im in Chesapeake bay, about midway up so the water is mostly light brackish. Not really salty. We will see how them look. in the fall.

 

[tpenfield]

looks like barnacle growth and other things.

Hey @tpenfield can you post a link to your prop painting thread

https://forums.iboats.com/threads/first-time-spraying-outdrive-anti-fouling.732285/

Salted water . . . You will need to paint the props. You could do galvanizing (zinc) spray and it will keep the barnacles from growing on them, but algea will grow on them. If you paint with zinc and then Trilux 33 outdrive paint, they should stay fairly clean if you boat stay in the (salt) water.

Every few years, I take the props down to bare metal. Pre-heat them in the oven, then hit them with the zinc paint while they are still hot. Then paint the props along with the rest of the outdrive.

It's a salt water thing. Putting the zinc right on the propellers is also helpful for corrosion, as it puts a weak metal in direct contact with the all-might stainless steel.

 

[Chris1956]

Don't paint SS props. That will allow marine growth and corrosion, due to the copper component of the paint. You will want extra zinc anodes with SS props.

Wire brush/sand them clean each spring. Wax can assist as well.

 

[Scott Danforth]

Don't paint SS props. That will allow marine growth and corrosion, due to the copper component of the paint. You will want extra zinc anodes with SS props.

Wire brush/sand them clean each spring. Wax can assist as well.

would love to see the sources on painting causing marine growth and corrosion.

 

[stormyj]

Decided to talk to the horse. From his mouth...

 

[dingbat]

Im in Chesapeake bay, about midway up so the water is mostly light brackish. Not really salty.

Where are you at?
Anywhere you can fill a salt shaker off the transom at the end of the day (Solomon’s south) is a bit more than “light brackish, not really salty”

If it came off with muriatic it’s either organic as in dried slime or oxidation in the form of chromium oxide. Check the condition of your anodes.

 

[stormyj]

Where are you at?
Anywhere you can fill a salt shaker off the transom at the end of the day (Solomon’s south) is a bit more than “light brackish, not really salty”

If it came off with muriatic it’s either organic as in dried slime or oxidation in the form of chromium oxide. Check the condition of your anodes.

Were in twin beaches area. Anodes are all pretty eroded. Changing them all before putting back in the water. Also, changing the continuity grounding cables. All were broke or gone. The last guy didnt do a good job taking care of it. All in all, the outdrives look ok. No real corrosion. And now the props are in better condition.

 

[Texasmark]

The original OMC SST [Stainless Steel Teflon ( coated to resist corrosion)] was coated for that reason. I bought one when they first came out in 1973 and the coating worked. Apparently they didn't have enough Crome/Zinc in the mix and if you worked a lot of sandy shallow water and wore the coating off, in fresh water, they would show rust pitting....assuming salt water would be worse and invite marine growth.

 

[dingbat]

Were in twin beaches area.

Called the Rod and Reel home port for many years..

 

[stormyj]

Called the Rod and Reel home port for many years..

We just got a slip at RnR.

 

[Sea Rider]

Is it possible to paint props with electrostatic paints or laminate/cover them up in hot plastic dips ?

Happy Boating