I figured I needed a flexible scraper, a wire brush, some sandpaper, and maybe a Scotch-brite pad or two. I started with the scraper. I chipped the remnants of the barnacles and other stuff off...slowly. This stuff is like cement. It took quite a while with the scraper before I got down to the bronze. For the tight spots where I just couldn't work the scraper, I ended up using the wire brush and sandpaper. After I got the prop clean, I went over it with the sandpaper to get the last bits off the prop. I think it took about 3 hours per prop to get them reasonably shiny and clean. The truth is, I never used the Scotch-brite, I quickly realized that a Scotch-brite didn't have a chance.
|1/3 of a clean prop|
Originally, I wasn't intending to coat the propellers with anything, but after all the work, I was re-evaluating that decision. I couldn't use bottom paint since the ablative paint wouldn't stay on the props for long. Fortunately, there are a few prop coatings available. In doing my research on propeller coatings, I found out that Rust-oleum Cold Galvanizing Compound is virtually the same stuff as one of the propeller coating products...and at $7, it was an economical alternative to the $22 can of official propeller coating. So, I got a can of it to give a try.
|Shiny prop with sad looking zinc|
Painting the propeller was pretty easy. Simply mask off the area from overspray and apply a couple light coats of paint and let it dry. The props aren't shiny anymore, but hopefully they'll resist some growth or, at least, may be a bit easier to clean. Guess I'll know next time we haul the boat how effective it is.
One last task and the props will be ready to go. That broken piece of metal at the end of the props in the above pictures were the remains of the sacrificial zincs and they obviously needed to be replaced. Simply remove the alan head bolt holding it on and replace with a new zinc. Yeah, right. One zinc came off just fine, the other bolt would not budge. I broke a hex wrench trying to get it off. Fortunately, the prior owner had a supply of zincs AND prop nuts, so I ended up having to remove and replace the prop nut as well as the zinc. I replaced the prop nut, bent up the tab on the keyed washer to lock the nut in place, then installed the zinc with a little Lock-tite on the hex bolt.
|Painted prop with unpainted nut and new zinc|
So, other than the touch up bottom paint where the stands are covering the bottom, the underwater surfaces should now be ready to go back in the water.