brass prop question

uspsjuan wrote:

cant find anyone who makes brass props for trump's Nimitz. not the flat PE ones, but the ones with the right contours. anyone know where i can find some?

check Great Models try searching under Brass props.

BTW real ships screws are actually a Bronze alloy not brass.

Not only are they not brass, but they aren't shiny eithr. The only time that you'll see any shine is after they have been machined and buffed after an overhaul , which isn't very often. They dont stay shiny for any length of time, either, as they take on an oxidized dullness after exposure to the elements. Props are actually a kind of a dull brassy brown color.

That's actually really interesting to hear.  Is the dull brown/brassy hue you mentioned anything like the following?:

I'd like to know how people approach getting exactly this sort of finish on their props.  I can think of some ways myself but it's a common task that must have some best practices to be learned from.

Mikeym_us wrote:

BTW real ships screws are actually a Bronze alloy not brass.

Are there any Aftermarket companies that actually make them out of bronze?  They would look better IMHO.  Go to a hardware store and look at their Bronze Bearings to see what the difference is between brass and bronze.

BGuy wrote:

That's actually really interesting to hear.  Is the dull brown/brassy hue you mentioned anything like the following?:     I'd like to know how people approach getting exactly this sort of finish on their props.  I can think of some ways myself but it's a common task that must have some best practices to be learned from.

That is a good finish on that prop, especially with the hull bottom being free of seagrowth. This hull looks like it hasn't been out of drydock for too long.

uspsjuan wrote:

cant find anyone who makes brass props for trump's Nimitz. not the flat PE ones, but the ones with the right contours. anyone know where i can find some?

Assuming you are looking for 1:350 scale (you didn't state) 5-blade props, a quick search didn't show anything appropriate among the large scale static and RC products.   At 21 feet in diameter, the props should scale out to a bit less than 3/4 inch.   The smallest functional brass 5-blade prop I was able to locate was 1-inch.  From there they range up to 3-inches.  (Siteck, Cornwall, Raboesch)

There is a company called G-Factor which has done some props for the 1:72 Gato and 1:144 Fletcher.   There was a product list I fould identifying props for the big Akagi (1:350 scale).   They may have something in the works for a Nimitz.  Otherwise you may be limited to PE blades.

(EDIT - Since you already know about G-Factor, you may be SOL)

If you're looking for a smaller scale.   Stick with PE or plastic

Mikeym_us wrote:

Oh and not to meantion that some model of Ships screws actually had variable pitch blades. And some had removable blades so that damaged blades could be changed out faster.

google-images 'Nimitz Propeller'

I don't see indications of replaceable blades or variable-pitch

The 'fingered strips' on the blade edges help protect it against knicks during transportation and installation

EdGrune wrote:

Mikeym_us wrote: Oh and not to meantion that some model of Ships screws actually had variable pitch blades. And some had removable blades so that damaged blades could be changed out faster. google-images 'Nimitz Propeller' I don't see indications of replaceable blades or variable-pitch The 'fingered strips' on the blade edges help protect it against knicks during transportation and installation

I work at a shipping canal and have seen replacement propeller blades on the aft superstructure of freighters.

And is that the same type of propeller as used on the Arleigh Burke?

Mikeym_us wrote:

And is that the same type of propeller as used on the Arleigh Burke?

No, different.  You can see the variable pitch swivels around the hub.   Also note how the blades are notched to allow them to go to zero pitch.

I believe that all the turbine powered ships;  Burkes, Ticos, Sprucans, Perrys all have/had variable pitch props.    The engine turns the prop shaft at a constant speed.  Power is extracted by varying the pitch

Mikeym_us wrote:

EdGrune wrote:  Mikeym_us wrote: Oh and not to meantion that some model of Ships screws actually had variable pitch blades. And some had removable blades so that damaged blades could be changed out faster. google-images 'Nimitz Propeller' I don't see indications of replaceable blades or variable-pitch The 'fingered strips' on the blade edges help protect it against knicks during transportation and installation

The screw in this picture is as shiny as you will ever see. The props are not polished per se, but buffed up with a grinder with a wire wheel which gives it that striped look. There is no uniform gloss on a shined up prop.

Also, the USN recycles rudders, props and anchors from decommissioned ships to new ones. I believe the anchors on the T Roosevelt are off of the Ranger as are the rudders on the G W Bush.

Oh sure, they toss plenty.. especially near the end of the fiscal year

The fact is, any standard "assembly" such as a anchor or radar, etc. can be re-used after overhaul and repair. They've been doing that for a while; I have documents from WWII (OK, scans of them) where Mk 51 gun directors from one ship were taken off during that ship's overhaul, overhauled separately themselves, returned to a pool, and installed on another ship when it came in for overhaul.

The old big guns were the same way; Arizona's #2 turret guns were put in Nevada when she came back for overhaul after Normandy and Toulon and exacted some revenge when they pounded Japanese positions at Iow Jima and Okinawa.

When I was on the Lexington in Pensacola,Florida, I saw machinery being replaced in the engine and boiler rooms that came off of the USS Alabama which was tied up nearby in Mobile. The Lex and the Alabama shared a lot of common equipment that was no longer being manufactured any longer. I understand that there is only one complete machinery space left out of four on the Alabama and it is the one on display. The rest have been canibalized to ssome extent.

I also recall removing pump motors and other equipment from deactivated ships at the naval shipyard where I work for use on active ships. Sometimes it is just easier to take a used piece of equipment than to go through the hassle and delay of obtaining a new one.

(My shipyard built the Alabama, by the way)

mfsob wrote:

Sheesh, subfixer ... does the Navy ever throw anything away???

If it was a bigger scale I would def go brass. I weathered mine in saltwater and hydrochloric acid, nice dull, spotty, iccky finish! http://www.rokket.biz/models/modelsweb/rokket/u557/prog1.shtml

But for small plastic the metallizer suggested, maybe with some drybrushing of greeny crap dulling, could work a treat.

And true, bronze was the metal (is) used, but brass is an excellent substitute, both bronze and brass are made from copper, and once weathered, look very similar.

Keep us posted on your prop progress!

Some small props are made of stainless steel (expensive stuff, and will still pit somewhat), I think aluminum would be too soft. Normal (mild) steel would require constant painting to resist rust and the motion of the prop would probably wear the paint away from the leading edges in no time at all.

Bronze, with its copper component, resists seagrowth and attains a natural patina that resists corrosion.

Saltwater and oxygen are powerful!

Uboats ran out of bronze by 42-ish, and switched to steel. They were desperate.