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"Brass props"

Posted: Wed Sep 13, 2017 4:30 pm
by ryanjames170
What are the Michigan brass props made from?

Re: "Brass props"

Posted: Wed Sep 13, 2017 5:31 pm
by CaptChuck
Is this sort of like who is buried in Grant's tomb?

Re: "Brass props"

Posted: Wed Sep 13, 2017 6:01 pm
by wbeaton
Bronze

Re: "Brass props"

Posted: Wed Sep 13, 2017 6:29 pm
by green thumbs
"Bronze" and "Brass" do NOT tell you very much. For instance cartridge cases are made of cartridge brass...70% Copper and 30% Zinc. Tobin Bronze is 70% Copper and 30% Zinc and up
to 1% tin....your math and mine add up to 101% Go Figure.
Tobin Bronze was used for prop shaft on what were called cabin cruisers and also on
certain war time Canadian coins instead of nickle.
Alloys of Copper may be called Bronze, Brass or a trade name such as Muntz Metal. Foundry practice vary
so the exact composition of alloy will differ from lot to lot and as well as foundry to foundry.
Local brass foundry makes copper tubing using recycled metal...they try to keep lead content
below an allowed amount, but, that depends upon what they get from scrap yard.
Not much metal sourced from refinery so alloy will vary to some degree.
I expect Michigan Wheel is more interested in how well metal machines and holds up in use
rather than exact Chemical Analysis.
High prices paid for metal scrap resulted in a lot of old outboards going to junk yard.
I bought a few there.
Louis

Re: "Brass props"

Posted: Wed Sep 13, 2017 7:41 pm
by FrankR
It's been more years than I care to think about, but back in the day, (as I sort of remember it) it seems like Michigan had their own name for their brass. Nybral?? Or something of that nature??

Re: "Brass props"

Posted: Wed Sep 13, 2017 7:56 pm
by Kerry
My 1989 MW catalog calls it Michalloy K. They were NIBRAL, a bronze alloy of brass, aluminum, and nickel, obviously their proprietary blend.

Re: "Brass props"

Posted: Thu Sep 14, 2017 12:57 pm
by ryanjames170
the reason i am asking is i want to figure out how to weld to it so i can build up the prop to re do it a little.

Re: "Brass props"

Posted: Thu Sep 14, 2017 4:28 pm
by Jeff Register
Is it broken now? Yes, Try a little heat to see what it turns out to be. Bet a coated brass rod would work, & thanks Louis for the analogical reply,
What happened in the 50's to 60's was an open market...............anything went back then!

Re: "Brass props"

Posted: Thu Sep 14, 2017 4:44 pm
by ryanjames170
Not broke nor in overly bad shape but I want to make it look nice and also cut threw the water good too, it's on a 15HP Johnson

Re: "Brass props"

Posted: Thu Sep 14, 2017 6:34 pm
by amuller
Brass and Bronze are terms used very loosely. But in a general sense, "brass" tends to be an alloy of copper and zinc, often with some lead content. This type of mix does not fare well in water, especially salt water, as the zinc is reactive and tends to dissolve, leaving a no-strength copper sponge.

"Bronze" tends to be a mix of copper and tin, and is both stronger and less subject to electrolytic corrosion. Stronger, often proprietary, alloys have nickel and chrome, etc, and get expensive.

So hopefully people are not making brass props except as decorations. Many people have made the mistake of fastening a boat with brass rather than bronze screws. Brass is fine for decorative items, low pressure fittings, etc.