Prop Hardening

[Buckshot]

Anyone care to share how you are hardening your props?

 

[Terry Keeley]

Tom Prezenka once told me that Octura props are 20C (C82500) so for that you first heat through at 1450F (20 mins or so) and water quench, it's then dead soft and perfect for finishing/bending etc.

Next you harden at 625F for about 3 hrs and slow cool. Don't try bending on it after that, lol. Holds a great edge too.

https://materion.com/-/media/files/...fs---heat-treating-copper-beryllium-parts.pdf
Without a kiln you can heat evenly to a dull orange with a torch (do it in the dark) , then stick it in the kitchen oven and run the cleaning cycle. Wala, hardened props and happy wife.

I've tried to find out what alloy Jim at ABC uses but haven't had much luck, seems it's a secret or something.

 

[Buckshot]

Thanks Terry! I ran a couple through the oven on the clean setting for about 3 hrs and they definitely got harder. Just curious if there was a better way (without a kiln).
I’ll try the torch first next time.

 

[Mark Anderson]

For octura props, I put them in the oven at 500deg. for three hours. Turn the oven off and let it cool. Leaves the prop hard, but still workable

 

[Brad Christy]

Guys,

My preferred heat treating shop does BeCu for $1.25/lb - $65 minimum (52lbs). This may seem kinda spendy, but if you've got a handful of props that you are ready to harden, the piece price comes down considerably, and there can be certainty in the process. It's also done in a vacuum, minimizing oxidation and fuming (pretty nasty with beryllium). I'd say most of us have a heat treating shop somewhere nearby, nestled within your closest industrial area. Have a look around. Talk to them. Trust the professionals.

Something to think about.

Thanks. Brad.
Titan Racing Components
BlackJack Hydros
Model Machine and Precision LLC

 

[Stuart Barr]

Found my notes on hardening. These are the old equations from years back:
ABC props: Harden at 600* for one hour and let air cool
Octura props: Harden at 625* for 3 hours and let cool in oven
Now I am running mostly the new ABC's and found this to be about the best. It is not brittle and will allow some repitching if moderate.
575* for one hour. Let air cool.
If you need to anneal a prop after hardening, Octura's run at 1250* and Octura's at 1450* for an hour. Quench in oil, not water. Water boils away.
Stu

 

[Buckshot]

Found my notes on hardening. These are the old equations from years back:
ABC props: Harden at 600* for one hour and let air cool
Octura props: Harden at 625* for 3 hours and let cool in oven
Now I am running mostly the new ABC's and found this to be about the best. It is not brittle and will allow some repitching if moderate.
575* for one hour. Let air cool.
If you need to anneal a prop after hardening, Octura's run at 1250* and Octura's at 1450* for an hour. Quench in oil, not water. Water boils away.
Stu

Thanks Stu!

For octura props, I put them in the oven at 500deg. for three hours. Turn the oven off and let it cool. Leaves the prop hard, but still workable

Thanks Mark!

 

[SayMikey]

My son wraps them in foil and throws them in the coals after the steaks are done. Sounds crude but if you bend on one very much after this process it chunks

 

[Ray Sametz]

My son wraps them in foil and throws them in the coals after the steaks are done. Sounds crude but if you bend on one very much after this process it chunks

And Dad works the hand bellows blower.

 

[Wasted wages]

Not sure beryllium fumes in the house and food cooked in the oven after that would be good for ones health...

Just "food" for thought...

 

[Alan Elzer]

Found my notes on hardening. These are the old equations from years back:
ABC props: Harden at 600* for one hour and let air cool
Octura props: Harden at 625* for 3 hours and let cool in oven
Now I am running mostly the new ABC's and found this to be about the best. It is not brittle and will allow some repitching if moderate.
575* for one hour. Let air cool.
If you need to anneal a prop after hardening, Octura's run at 1250* and Octura's at 1450* for an hour. Quench in oil, not water. Water boils away.
Stu

Thnx Stu

 

[John Beardslee]

Sorry, I missed seeing this earlier, had to make a quick run to FL.
My recipe was provided to me by a metallurgist from Brush Wellman, my source for BeCu 20 ie: 2% Berillium Copper. I actually took props to him to see.
Here’s how I did it. I used small bread baking tins, put notches along the top rail from short pieces of shafting to hang props. I would place in my electric atmospheric furnace at 1000-1100 F for 30 minutes, I quenched in distilled water that was at room temperature to full anneal the props. I swirled each prop in a figure 8 while quenching. City or well water has lots of minerals and forms extremely har oxides on the surface that are hard to remove.
Then I would hang the props on the bread tins again but this time I would tent the tin with aluminum foil. Placed them back in a 600 F furnace for 30 minutes and remove from furnace and air coil in the tented tin. This takes the as cast prop from 85,000 psi to 135,000 psi. In practical terms as cas is about 1/2 hard and after heat treatment to full hard. You can use any heat source to heat to anneal that you want and not leach berillium unless the go over 1500-1600F, if you use a propane torch just keep moving the flame around the prop and don’t hold it in one spot. I’ve use an instant read temp gun but the color is a dull red/orange as stated by others.
I have emails from Jim Allen and myself from years ago covering what Jimmy felt was the alloy that ABC new series props are made with and how to heat treat them. When I return to Michigan next week I will retrieve those emails and try to put together a summary for use. My re call is that it’s a little more involved process but doable.
Thanks John

 

[Zimmerman]

Back in the early 70's Jimmy Gale said the best way to harden a BeCu prop was to quench it in good old American pee. Not very high tech by today's standards, but it always worked for me. Something to do with nitrogen.

 

[Brian Sorgente]

Back in the early 70's Jimmy Gale said the best way to harden a BeCu prop was to quench it in good old American pee. Not very high tech by today's standards, but it always worked for me. Something to do with nitrogen.

Whenever I think of hardening props that's the first thing that comes to mind. I remember reading comments about people doing that in the past, but always wondered if they were playing games or being serious.

Brian

 

[John Beardslee]

The first I heard of it was from a custom knife maker in Kentucky by the name of Randall, he collect urine from his employees bathroom in is machine shop and used it to quench his knives, some of which went to the moon on some of the first trips. He said the acid in the urinate prevented the hard spots from developing on the surface. This was in the early 1970’s. When I stopped doing propellers in the 1990’s, John Ackerman (Indy) asked me for my heat treatment recipe. I gave it to him and told him of Randall’s urine quench but suggested he might prefer the distilled water due to the Oder while quenching. Fast forward to 6-7 years ago and Norm Doerr (Hobby Heat Treating) told me Ackerman added it was cat urine and wondered how I collected it! Too funny!
Thanks John

 

[John Beardslee]

All my contacts in metallurgy have all passed but if anyone out there knows someone, I think a recipe that would result in a 3/4 hard prop would work really well for heat racing as I think you could still tweak it. Full hard is excellent for Saw & 2 lap but can fatigue and throw a blade over extended use in heat racing. And if you try to tweak one it most likely will crack or break.
Thanks John

 

[Zimmerman]

I was originally from St. Louis, but I knew Ackerman back in the 70's and he was a bit of a trixter. Old "Speedy John" would bring different colored fuels to the practice pond. Every one crowded around to see which one got the best results and try to get the formula. Snicker, snicker same fuel different food coloring!!!

 

[Ray Sametz]

I was originally from St. Louis, but I knew Ackerman back in the 70's and he was a bit of a trixter. Old "Speedy John" would bring different colored fuels to the practice pond. Every one crowded around to see which one got the best results and try to get the formula. Snicker, snicker same fuel different food coloring!!!

John Finch used too write on his fuel bottles( 10% more then yours) to keep everybody guessing.

 

[John Beardslee]

We had GREAT FUN back in the day!!! God I can’t believe I lived through all this! But if what I remember is of humor or??? to any of you? Enjoy! Can’t believe at my age I can still do this but by the Grace of God! Yup I still fly heli’s too!
Thanks John

 

[SayMikey]

Not sure beryllium fumes in the house and food cooked in the oven after that would be good for ones health...

Just "food" for thought...

Charcoal Grille