I got lucky!

[boatpoker]

Which is why NIBRAL is so popular, especially on highly loaded props. No zinc and stronger than pure bronze. There are many good sources and information on the Internet as BP suggests. Michigan Wheel as previously mentioned is one.

Never seen nor heard of a "pure" bronze propeller, usually phosphor bronze. By the way Nibral is just another a bronze alloy.

Professional Boatbuilder Magazine has an excellent article on this issue.

 

[BruceK]

Apart from composition issues,I understand props can be reconditioned, including adding metal. Is that just for re-balancing, nicks, and bend repairs, or can "dezincification" be remediated ?

 

[boatpoker]

can "dezincification" be remediated ?

The cost to do it well would be extreme and the chances of doing it well are slim. Simply not worth it unless maybe you are dealing with a 25' diameter ships screw and I don't think they are using manganese bronze any more

 

[Benthic2]

Donson: I think ouboards and I/Os use Stainless because at high speed the aluminum blades bend and lose some of their curve so they become less efficient.

 

[Art]

Never heard nor seen one - but - wonder what Monel would work as prop material. Expensive I imagine but long lasting I believe.


https://en.wikipedia.org/wiki/Monel

 

[BruceK]

D H Porter in Sydney are prop,shaft and bearing mfrs and repairers, making props in bronze,nibral and aluminum (according to their website). They made me a new shaft(for the boat, thanks)and renovated the prop, I think they needed the prop anyway to make the terminal of the shaft. They have a good reputation, know how to charge for it, but they are good. Whatever magic they worked I got a smooth running and turning port shaft and prop, turned out a PO had "used" the shaft to lift a mooring.

 

[gaston]

I don't know or care what my prop is made of but I bet it outlasts me .Dose it relay matter what its made from ???

 

[FF]

"or can "dezincification" be remediated ?"

Usually done by melting the prop , adding missing metals and recasting.

Common in 3rd world .

 

[High Wire]

Couldn't resist ... 99% of the propellers on cruising boats are "Manganese bronze" which is actually classed as a brass due to it's high zinc content and subject to dezincification if cathodic protection systems are not kept up or if stray current is an issue. Nibral is a proprietary bronze alloy and quite rare due to their high cost. True bronze props are very rare again due to their very high cost.

How can you tell if it's true bronze by looking at it?

 

[HiDHo]

Interesting thread, I have the builders specs for my prop but the materials used don't fit any of the periodic symbols ? Thought I'd see Cu Copper, Sn Tin and Mn Manganese, I guess the letters they used in the material section are there own stock codes.
After thirty years of use the only wear and tear is some slight erosion/pitting so it most be a good compound of metals.

 

[HiDHo]

Bronze


Brass

 

[stubones99]

Here is a propeller with plastic adjustment strips to let you change the pitch of the prop by changing the height of the plastic strips...

VEEMStar Series | VEEM Propellers

Make sure to lockout before diving in.

 

[FF]

" I think ouboards and I/Os use Stainless because at high speed the aluminum blades bend and lose some of their curve so they become less efficient."

Perhaps, tho for a long time small 18Hp OB could purchase plastic props ,

that were claimed to loose pitch at high loads and low speeds ,

and regain the pitch as the OB came up to speed.