Prop re-pitching and casting.

[JS_Racing]

Hey Terry,

Why not consider using your modified prop as a plug and sand casting a new solid prop?

http://www.foundry101.com/new_page_7.htm

 

[lohring]

Sand casting is not even close to the accuracy and fine detail you need. Lost wax casting is what is used for all the commercial props. One off props can be made by wax welding blades onto a wax hub with either a pitch block to form the blade or tooling like Terry's. Props can be custom cast from chrome colbalt alloys by any dental lab that makes partial denture frames. That's how Joerg made his props that went 140 mph.

However, Terry's method is quicker and easier. It probably will be used to set gas hydro SAW records next weekend at Legg Lake.

Lohring Miller

 

[Terry Keeley]

Sent it back to my Engineering dept., here's what they came up with. :lol:

Now the guys in Fabrication can rotate the blade holders, lock the angle down and pull them apart for brazing.

Now to make another prop!

 

[dwilfong]

WOW Terry that is the bomb.

Put one more adjuster on it so it will hold the blades as you cut the hub out. then you can move the blades in and re-cut.

That way you can change the dia and keep the same blade profile.

 

[lohring]

I just got some reports from the Legg Lake SAW event of strength problems with beryllium copper props. We have run props with cut and brazed blades on gas boats. However, we have broken blades on thinned props on electric boats. Be careful.

Lohring Miller

 

[Tim Kish]

Looks like the Engineering and Fabricating departments are going to get a good Christmas bonus this year.

Great work Terry .

 

[Terry Keeley]

WOW Terry that is the bomb.

Put one more adjuster on it so it will hold the blades as you cut the hub out. then you can move the blades in and re-cut.

That way you can change the dia and keep the same blade profile.

Not a bad idea, might work on that down the road...

I just got some reports from the Legg Lake SAW event of strength problems with beryllium copper props. We have run props with cut and brazed blades on gas boats. However, we have broken blades on thinned props on electric boats. Be careful.

Lohring Miller

Thanks, will play safe. Even my heat race props throw a blade once and a while, doesn't seem to do any damage. I like 'em thin!

Looks like the Engineering and Fabricating departments are going to get a good Christmas bonus this year.

Great work Terry .

Yup, now to just get the guys in the field to run that number they've been looking for...

 

[Terry Keeley]

Think I got a good joint this time, when the parts got to the right temp. the springs pushed them together.

 

[shoboat]

Terry,

I may have another brazing rod for you to try if that does not hold up?

Send me your address in a PM please.

I will ship you a sample for free.

Thanks,

Mark Sholund

 

[Terry Keeley]

Terry,

I may have another brazing rod for you to try if that does not hold up?

Send me your address in a PM please.

I will ship you a sample for free.

Thanks,

Mark Sholund

Thanks much for the offer, lemme run this and I'll let you know.

What's the rod specs?

 

[shoboat]

Terry,

I will have to look up the numbers as we get it bulk quantities.

We braze copper line sets together with this and it is harder than the copper itself

After it is brazed in place. You are going to need some heat to use this rod, we use

Dual welding tanks to get it hot enough.

Let Me Know How This One Works For You?

Mark Sholund

 

[Terry Keeley]

Terry,

I will have to look up the numbers as we get it bulk quantities.

We braze copper line sets together with this and it is harder than the copper itself

After it is brazed in place. You are going to need some heat to use this rod, we use

Dual welding tanks to get it hot enough.

Let Me Know How This One Works For You?

Mark Sholund

Sure will, forgot you were an HVAC guy!

 

[El Zorro]

I think I would have chamfered the edges of the blades a bit more where they join the hub. Maybe leave more fillet material where the blades join the hub this time, ehh?

Great looking work, Terry!

Dick Tyndall

 

[dave roach]

Terry

Test time.

Dave

 

[Terry Keeley]

I think I would have chamfered the edges of the blades a bit more where they join the hub. Maybe leave more fillet material where the blades join the hub this time, ehh?

Great looking work, Terry!

Dick Tyndall

Ya eh? :lol: I "pre thinned" the blade roots so I can have the blades thin the way I like 'em but leave a fillet this time.

Thanks!

Terry

Test time.

Dave

About 6 hrs. more work then hopefully the winds die down here before the water gets hard... :unsure:

 

[Olly]

Terry

I think you should make a prop guard for your stand LOL

Olly

 

[Blackout]

Fantastic work Terry!

Problem is when the winds die down this time a year, the water freezes over night. Wake up with a thin layer of ice.

 

[Marty Davis]

Terry:

Remember that the hub of the prop doesn't see much water at al (mostly hidden by the strut)l and the fillet can be very large there to support the blades. The amount of solder fillet is primary to the strength of the total prop.

 

[Terry Keeley]

Terry

I think you should make a prop guard for your stand LOL

Olly

lol! How 'bout this?

Fantastic work Terry!

Problem is when the winds die down this time a year, the water freezes over night. Wake up with a thin layer of ice.

Wonder if this will work on hard water?

Terry:

Remember that the hub of the prop doesn't see much water at al (mostly hidden by the strut)l and the fillet can be very large there to support the blades. The amount of solder fillet is primary to the strength of the total prop.

This 45% stuff doesn't fillet very well, tends to run right off.

Might try another braze they recommend for filleting (35% Ag) or even lazer welding as my toolmaker buddy suggested. He said they get a lot of BeCu molds lazer welder where he works...

 

[Terry Keeley]

Got it cleaned up a couple days ago, too bad winter's come early this year (-13C the other night) and the water's hard.

Spring's just around the corner!