Prop re-pitching and casting.

[charles siler]

Terry nice work heres a good one for you if you are needing to fix porosity laser welders work super to fill build up or work harden. Check with your local jeweler . Awesome Charles

 

[Jim Allen]

why spend 30-40 hour's

lol! I wish this was I all had into this project...

Terry,

When I return to the shop I'll give you the information, with photos, of the lost wax investment procedure that Ed Kalfus & I used to make hundreds of BeCu & 17-4 stainless steel propellers. Both metals can be easily heat treated after casting to their ultimate tensile & yield strengths. There is nothing special needed to make the wax blades that the casting house will mount to a tree which is then placed in the casting sand box. Baking hardens the casting sand & melts the wax out before pouring in the molten metal. Both of these alloys can be cast in very thin sections without voids or porosity.

Jim Allen

 

[Terry Keeley]

why spend 30-40 hour's

lol! I wish this was I all had into this project...

Terry,

When I return to the shop I'll give you the information, with photos, of the lost wax investment procedure that Ed Kalfus & I used to make hundreds of BeCu & 17-4 stainless steel propellers. Both metals can be easily heat treated after casting to their ultimate tensile & yield strengths. There is nothing special needed to make the wax blades that the casting house will mount to a tree which is then placed in the casting sand box. Baking hardens the casting sand & melts the wax out before pouring in the molten metal. Both of these alloys can be cast in very thin sections without voids or porosity.

Jim Allen

Thanks Jim, I would be very interested in that. Did you guys actually cast 17-4 yourselves? I'm having some trouble with it...

 

[Terry Keeley]

Terry nice work heres a good one for you if you are needing to fix porosity laser welders work super to fill build up or work harden. Check with your local jeweler . Awesome Charles

Thanks! Wish I had that little welding unit you have...

 

[charles siler]

Terry nice work heres a good one for you if you are needing to fix porosity laser welders work super to fill build up or work harden. Check with your local jeweler . Awesome Charles

Thanks! Wish I had that little welding unit you have...

Ha ha $34thou and you can! If it wasn’t so expensive for shipping I would fix them no problem. How are keeping the Bore straight?

 

[Jim Allen]

why spend 30-40 hour's

lol! I wish this was I all had into this project...

Terry,

When I return to the shop I'll give you the information, with photos, of the lost wax investment procedure that Ed Kalfus & I used to make hundreds of BeCu & 17-4 stainless steel propellers. Both metals can be easily heat treated after casting to their ultimate tensile & yield strengths. There is nothing special needed to make the wax blades that the casting house will mount to a tree which is then placed in the casting sand box. Baking hardens the casting sand & melts the wax out before pouring in the molten metal. Both of these alloys can be cast in very thin sections without voids or porosity.

Jim Allen

Thanks Jim, I would be very interested in that. Did you guys actually cast 17-4 yourselves? I'm having some trouble with it...

No. We did not do the pouring of either metal into the molds. BeCu is very tricky because it must have it's own dedicated crucible that has not been used for melting other alloys. Even with elevating a crucible to 4,000 * F, this will not clean it good enough for casting BeCu. Failure to follow this rule will not become evident until the BeCu props are heat treated. THEY WILL BECOME DISTORTED & TWISTED during heat treating!! It is really something to see happen after all the prop work has been completed. The casting house where we had this done was also casting rifle receivers in 17-4 PH. They only needed to be machined inside with very little finish work on the outside.

JA

 

[Terry Keeley]

Terry nice work heres a good one for you if you are needing to fix porosity laser welders work super to fill build up or work harden. Check with your local jeweler . Awesome Charles

Thanks! Wish I had that little welding unit you have...

Ha ha $34thou and you can! If it wasn’t so expensive for shipping I would fix them no problem. How are keeping the Bore straight?

Only 34K! Ha! I may havta re-mortgage the house but I'm looking into a lazer profiler and five axis CNC so I can do these things right!

Bore straight?

 

[Bradley Ward]

https://sylatech.com/try these guy's for prototyping they specialize in lost wax casting and maybe worth a look? The old saying is Speed is just a question of money! How much can you spend! Definitely not a case of bagging any one's work as on the dumb scale i could be a number 1! How fast is the tip speed of a Katana swung by master? Faster than a 125mph (do the maths!) Not 1 of my suggestions may be practical! Cost effective! Even worth a look! But suggestions are only suggestions for a reason. My Dad designed a de-icing system used by Boeing and had design's used at Lockheed Martin's Skunk Works in area 51 not bad for a guy working out of a $500 shed

 

[Jim Allen]

Terry,

Sorry to take so long to answer, but I've been in Moseley getting things prepared for the new house. The steel master in the photo is used to make a silicone rubber mold. The steel master is made 15% bigger than the cast propeller to compensate for shrinkage. The steel master has blades which are silver soldered into the prop hub. High temperature silver solder is used & the propeller is hardened (1450 F+) while being silver soldered. After hardening in oil, the propeller is tempered blue to a spring temper. Then the blade is tested at the lake before casting investment wax copies are made. A silicone rubber mold is used to make wax castings for the lost wax process that Bradley's post describes. Keep in mind that when casting any beryllium copper alloy, you MUST use a dedicated melting pot that has not been used for any other alloy. If the melting pot is contaminated, the beryllium copper blades that are cast will distort when they are heat treated. Cutting the silicone mold properly will allow the cast wax blade to be removed without damage. Notice that the silicone rubber mold is made in a mesh expanded steel cage. Also notice that the propeller's shaft is held in place before the wax is pored in. It will be removed before the wax casting is removed from the mold. This ensures alignment of the propeller shaft hole with the OD of the hub. Shrinkage of the casting wax will require the hole to be reamed to size. The same wax castings are used to cast 17-4 PH stainless. Notice in the last photo that the drive dog is also cast into the wax propeller.

Jim Allen

 

[Terry Keeley]

Pretty cool stuff Jim, especially that you guys did it so long ago. I find the trick is to get good wax and that was a whole learning curve in itself.

I've got three raw castings of one pitch done (7" LE pitch as I measure it) and have redone my master for another set with 8" pitch. Cutting the clear RTV mold right on the edge makes for good wax. Also re-did my frame to use less RTV making it easier to cut.

BeCu casts so well, no wonder they use it for all kinds of intricate parts. Still gonna give 17-4 another shot once these are done.

 

[timothy johnson]

Really nice work Terry!! When Jim mentioned Ed Kalfus a few days back I wanted to post some pics of a prop from that era of RC boating. The prop in the picture was a prop that Henry Parohl made for me to run with a .90 engine that he built for me to run in a White Heat 4-60 that I built. Henry ran tether boats with Ed in the early 60s. Henry was a tool and die maker for Bulova watch. Henry like Ed made all of his own engines and props. I feel lucky to have ever met guys like Ed and Henry.

 

[Terry Keeley]

Really nice work Terry!! When Jim mentioned Ed Kalfus a few days back I wanted to post some pics of a prop from that era of RC boating. The prop in the picture was a prop that Henry Parohl made for me to run with a .90 engine that he built for me to run in a White Heat 4-60 that I built. Henry ran tether boats with Ed in the early 60s. Henry was a tool and die maker for Bulova watch. Henry like Ed made all of his own engines and props. I feel lucky to have ever met guys like Ed and Henry.

Thanks for posting. I saw a bunch of Kalfus props that Gary Preusse had years ago, works of art. I even think Gary set a record with one of them.

 

[Terry Keeley]

 

[Terry Keeley]

 

[Terry Keeley]

 

[Jay Boyd]

Beauty, EH!

 

[Terry Keeley]

Beauty, EH!

TK3362, lol!

 

[Terry Keeley]

Look what's on the bench now!

 

[Mike Hughes]

Thats one hell of a prop anvil ball you got in the back ground. LOL To tell the truth. I have used them in the past to do some repairs to props.

Mike

 

[Terry Keeley]

Thats one hell of a prop anvil ball you got in the back ground. LOL To tell the truth. I have used them in the past to do some repairs to props.

Mike

I find the 2" ball just about right for 45 size and up props, adds a nice gentle cup. Nylon capped hammer works great too.

This ones's gonna be 63mm with 6.75" of LE and 7.75" of TE pitch.

Lessee, mph x rpm / pi = pitch. No that ain't it. pitch / mph = rpm. Naw that ain't it either...