Prop material.

[Jeffmaturo]

Wondering if there was any other metal out there that could replace beryllium? What percentage of the actual prop contains beryllium?

Thoughts about stainless steel props and aluminum.

Beryllium is a grey metal that is stronger than steel and lighter than aluminum. Its physical properties of great strength-to-weight, high melting point, excellent thermal stability and conductivity, reflectivity, and transparency to X-rays make it an essential material in the aerospace, telecommunications, information technology, defense, medical, and nuclear industries. Beryllium is classified as a strategic and critical material by the U.S. Department of Defense. In 2014, the U.S. produced 270 metric tons of beryllium domestically and imported 68 metric tons, increases from 2013 of 15% and 19% respectively. Government stockpile release is another source of beryllium. Bertrandite (<1% beryllium) is the principal mineral mined for beryllium in the U.S. while beryl (4% beryllium) is the principal mineral mined for beryllium in the rest of the world. (courtesy of OSHA)

 

[John Beardslee]

Wondering if there was any other metal out there that could replace beryllium? What percentage of the actual prop contains beryllium?

Thoughts about stainless steel props and aluminum.

Jeff the BeCu that Octura props used to be and I believe still are is 2% Be, I cast some out 302 SS as well as BeCu

Thanks John

Beryllium is a grey metal that is stronger than steel and lighter than aluminum. Its physical properties of great strength-to-weight, high melting point, excellent thermal stability and conductivity, reflectivity, and transparency to X-rays make it an essential material in the aerospace, telecommunications, information technology, defense, medical, and nuclear industries. Beryllium is classified as a strategic and critical material by the U.S. Department of Defense. In 2014, the U.S. produced 270 metric tons of beryllium domestically and imported 68 metric tons, increases from 2013 of 15% and 19% respectively. Government stockpile release is another source of beryllium. Bertrandite (<1% beryllium) is the principal mineral mined for beryllium in the U.S. while beryl (4% beryllium) is the principal mineral mined for beryllium in the rest of the world. (courtesy of OSHA)

 

[PaulHail]

There are certainly superior materials to make a prop out of, the question is can they be cast by small foundries in small lots at a competitive price. The alternative would be to contact a foundry such as Ruger to see about the minimum lot size to cast them out of one of the high alloy stainless steels.

 

[Terry Keeley]

Just went through this recently, thread here is you're interested:

http://www.intlwaters.com/index.php?showtopic=58438&page=1

Tried to cast 17-4 stainless but it's nearly impossible to melt unless doing it in a vacuum.

I ended up using 20C, same as Octura. When heat treated it has properties close to stainless steel in the as cast condition:

https://ibcadvancedalloys.com/home/products/beryllium-products/beryllium-copper-casting-alloys/

 

[John Beardslee]

Just went through this recently, thread here is you're interested:

http://www.intlwaters.com/index.php?showtopic=58438&page=1

Tried to cast 17-4 stainless but it's nearly impossible to melt unless doing it in a vacuum.

I ended up using 20C, same as Octura. When heat treated it has properties close to stainless steel in the as cast condition:

https://ibcadvancedalloys.com/home/products/beryllium-products/beryllium-copper-casting-alloys/

Yup, been there, glad to see things havent changed too much. The great thing about BeCu 20 is it pours like water and is great to work with. As cast it comes in at 70,000 psi and if you heat treat youll have 135,000 psi, a big number if you research.

Thanks John

 

[LohringMiller]

Dental labs that cast partial denture frameworks use chrome cobalt alloys. They vacuum cast them in an electric furnace giving a very strong and accurate prop. They're accustomed to one offs, but aren't inexpensive. I was quoted $80 for a casting from my waxup.

Lohring Miller

 

[Jeffmaturo]

Dental labs that cast partial denture frameworks use chrome cobalt alloys. They vacuum cast them in an electric furnace giving a very strong and accurate prop. They're accustomed to one offs, but aren't inexpensive. I was quoted $80 for a casting from my waxup.

Lohring Miller

That seems very reasonable.........

 

[Jeffmaturo]

Really never thought I would run an aluminum prop but tried one from the advice of a friend and was surprised just how well it worked.

 

[John Beardslee]

Really never thought I would run an aluminum prop but tried one from the advice of a friend and was surprised just how well it worked.

I know some of the electric boats are using them with good success. Ive seen some of the newer ones that look robust enough to hod up. One of the guys ran 108 mph at Flint in a twin electric cat

 

[Jim Allen]

I have heat treated C-20, modified C-20, 17-4 PH & several grades of tool steels used for propellers. The main advantage of the two beryllium copper alloys commonly used by manufacturers is in their ability to be heat treated many times, providing they are NOT heated to hot during the annealing process. The use of to high of a temperature during the annealing process will cause the beryllium to leach out & the result will be a propeller that can not hardened. A properly hardened beryllium copper propeller CAN NOT be bent after hardening! The blade will snap off!

The hardening process CANNOT be done in your wife's oven. LOL! The annealing process can be done with a propane torch & cold water.

Jim Allen