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post #21 of Old 04-14-2012
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Re: Epoxy on the prop?

As a pipe welder let me take a stab at it for Chris First of all the metal alloy must have zink and have less than it started with. Easy to figure out just from the word. Now lets start looking at some real world seen it kind of thing. Brass has zink. Brass valves will get this in two ways one is a plug dezincifcation. just like it sounds a pulg hole eats out you get a weep hole in the valve this is bad worst case. Fix a small hole braze it up and soon out pops a new hole in a new place. Just a poor quailty day. Little can be done hope you can keep going untill you can shut down and make a repair replacing valve asap. Broad surface decay dezincafcation is even pitting over the entire area could be more in high flow turbulent areas. You might polish this out and get more use this is not as bad. Both can have micro cracks but plug type will be deeper. White surface oxide is a big clue this is going on. Some of the new brass alloys have less zink and will stand up much longer. a real enginer might talk about ph levels, ( salt) flow, stagnation, temp, other factors. adjust them and you can extend the life and use valve with broad surface uniform corosion. Lots of salt will lead to plug type more than the other factors! The Kicker here is I speak of a brass valve and opinion. A brass valve is not a prop on a boat and it dose not spin. Still I think I have put some good views in this thread. Butterflys causing tusnmia joke?

Last edited by Lou452; 04-14-2012 at 01:14 AM. Reason: grammer
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