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-   -   Using Bottom Paint on Brass Propeller (http://www.sailnet.com/forums/gear-maintenance/98781-using-bottom-paint-brass-propeller.html)

73Morgan 04-23-2013 09:49 AM

Using Bottom Paint on Brass Propeller
 
Just polished up my brass propeller after 15 years of using ablative bottom paint on it. It polished up real nice, no corrosion damage. I was told I should use some fancy stuff ranging in price. It seemed like a lot of money, I had to understand what it was going to do for me. Found an old post on here which had some good alternatives (link below). Not giving up yet, I looked up galvanic reaction of various metals (second link below). A difference of hundreds of mill volts is likely to result in galvanic corrosion, but only a few tens of mill volts is unlikely to be a problem. Note that the numbers at the top are in Volts. The chart shows copper and brass in the same range. Plumbers have been mixing brass and copper for over 100 years with no problems. The paint I've been using is the cheapest I can find, it has Copper and Cuprous Oxide (principal oxides of copper), which I believe to be very common ingredients for bottom paint. I am not a scientist but it seems that this is just a bunch of nonsense with the brass props.

Interested in knowing what you guys think, or maybe shed some more light on the subject.

http://www.sailnet.com/forums/gear-m...-coatings.html

Galvanic Corrosion Chart*

Faster 04-23-2013 10:41 AM

Re: Using Bottom Paint on Brass Propeller
 
The prop will be bronze, not brass....

SimonV 04-23-2013 10:43 AM

Re: Using Bottom Paint on Brass Propeller
 
If its brass its too late.

sww914 04-23-2013 10:46 AM

Re: Using Bottom Paint on Brass Propeller
 
Slightly off topic, but my friends were stuck in one spot at anchor for 3 months with a dead engine. She put pieces of nylon stockings on the blades to protect them. After all that time, the nylon slid right off covered in barnacles and slime and cleaning the prop was a 30 second job.

73Morgan 04-23-2013 11:14 AM

Re: Using Bottom Paint on Brass Propeller
 
Quote:

Originally Posted by Faster (Post 1020238)
The prop will be bronze, not brass....

Color is brassy, I thought bronze has a bronze hue. Are all props bronze?

73Morgan 04-23-2013 11:17 AM

Re: Using Bottom Paint on Brass Propeller
 
Quote:

Originally Posted by SimonV (Post 1020240)
If its brass its too late.

Why is it to late?

Faster 04-23-2013 11:53 AM

Re: Using Bottom Paint on Brass Propeller
 
Quote:

Originally Posted by 73Morgan (Post 1020258)
Color is brassy, I thought bronze has a bronze hue. Are all props bronze?


Not all props are bronze, but I'm pretty sure there are no brass props.

SS, Aluminum, Plastic etc... but not brass.

DrB 04-23-2013 12:28 PM

Re: Using Bottom Paint on Brass Propeller
 
Quote:

Originally Posted by sww914 (Post 1020244)
Slightly off topic, but my friends were stuck in one spot at anchor for 3 months with a dead engine. She put pieces of nylon stockings on the blades to protect them. After all that time, the nylon slid right off covered in barnacles and slime and cleaning the prop was a 30 second job.

Clever idea.

73Morgan 04-23-2013 12:33 PM

Re: Using Bottom Paint on Brass Propeller
 
Faster, Thanks

I appreciate the correction it's a bronze prop. If I am reading the chart correctly copper is on the Anodic side of the two bronzes shown. Copper would then be the sacrificial metal to the bronze. So, it still makes sense to me that there is no problem with using bottom paint with copper in it on bronze props.

tommays 04-23-2013 02:23 PM

Re: Using Bottom Paint on Brass Propeller
 
WELL

There is bottom paint that is made for underwater metal


Not everything happens to things 100% of the time they are just general recommendations of what is considered good and bad practice

I can snap a picture next time I am inside a SS vessel from the 1970s were the SS blade locking pins got in a fight with the blade they were locking and as a result the pins SS pins LOST

I can go in its twin same age same place nothing happened


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