fuel system woes

the reserve tank feed is much larger than it really needs to be ... once you open it, all it needs is a flow rate greater than the fuel requirement of the engine .. so long as it can fill the main tank faster than the engine is emptying it once you switch over, that shoudl do it. 50mm is more than it needs IMHO, a 15mm pip would be way more than enough.
 

On machined brass/bronze you cannot tell by colour alone. On raw bronze, yes, the casting marks give it away, but once machined its hard to tell.

bronze with a bit of pinking

The "pinking" is de-zincification. This only occurs with brass, not bronze. The "pink" is where the zinc has been removed, leaving pure copper.

This cannot happen with bronze, as it does not contain any zinc in the first place.
 
On machined brass/bronze you cannot tell by colour alone. On raw bronze, yes, the casting marks give it away, but once machined its hard to tell.



The "pinking" is de-zincification. This only occurs with brass, not bronze. The "pink" is where the zinc has been removed, leaving pure copper.

This cannot happen with bronze, as it does not contain any zinc in the first place.

This isn't correct, Bronze props can go pink.
 
This isn't correct, Bronze props can go pink.

True bronze being an alloy of copper and tin cannot dezincify as there is no zinc in the alloy.

But some so called bronze's are not true bronze but in fact a brass which, of cause is an alloy of copper and zinc can de-zincify. Manganese bronze is an alloy of copper and zinc so is not a true bronze but is a brass.

There is also aluminum bronze which is an alloy of copper and aluminum but again cannot de-zincify as it has no zinc in it.
 
True bronze being an alloy of copper and tin cannot dezincify as there is no zinc in the alloy.

But some so called bronze's are not true bronze but in fact a brass which, of cause is an alloy of copper and zinc can de-zincify. Manganese bronze is an alloy of copper and zinc so is not a true bronze but is a brass.

There is also aluminum bronze which is an alloy of copper and aluminum but again cannot de-zincify as it has no zinc in it.

Propellers usually contain zinc.
 
So what are the alloying elements of a a boat propeller ?

Paul read this below and educate yourself

https://www.diffen.com/difference/Brass_vs_Bronze

I still do not require any education from you, but thanks for the kind offer.

There are many types of copper alloy that are referred to as bronze and that has always been the case. The earliest forms of bronze, dating back to the actual bronze age, did not even contain tin, they were an alloy of brass and arsenic.

The material used to make propellers is generally referred to as bronze, it contains various alloying materials, amongst them, zinc. CU1/2/3/4 all contain more zinc than tin and are used for propeller construction.
 
I still do not require any education from you, but thanks for the kind offer.

There are many types of copper alloy that are referred to as bronze and that has always been the case. The earliest forms of bronze, dating back to the actual bronze age, did not even contain tin, they were an alloy of brass and arsenic.

The material used to make propellers is generally referred to as bronze, it contains various alloying materials, amongst them, zinc. CU1/2/3/4 all contain more zinc than tin and are used for propeller construction.

Your highlighted comment is the salient point generally referred to a bronze but in metallurgy terms is brass. Bronze can have other alloying elements for different properties of the final metal.

Bronze was first 3500 BC where brass only 500 BC. Bronze is a much better metal metal for swords as used in the bronze age as brass. brass would be too soft for that application.

Stick to your electrical installation work and leave the proper Engineering to proper qualified Engineers.
 
Indeed so, "is generally referred to" is not really much of a standard is it.

If we were to classify things as what the great unwashed generally referred to them as, then we'd probably have to reclassify all polymers as "plastic" and divide wood into "pine" and "hardwood", and batteries would be "torch", "car" and "lorry" ...
 
Stick to your electrical installation work and leave the proper Engineering to proper qualified Engineers.

Bitchy comment.... What kind of properly qualified engineer knows these things... I have two kids who are engineers and they would not have a clue... But I know a few guys that work on lathes and drilling and welding machinery who call themselves engineers but of course they are not...who might. The guys in the brass founders probably would...

The world exists on imprecision in language...
 
The world exists on imprecision in language...

Not in engineering it doesn't.

If the great unwashed want to refer to all yellow metals as "brass" than fine, but they are wrong.

It may not matter the slightest in the world of curtain poles and buttons, but in marine engineering the difference between brass and bronze is significant and randomly swapping the names about leads to confusion.
 
Stick to your electrical installation work and leave the proper Engineering to proper qualified Engineers.

What kind of properly qualified engineer knows these things... .

Any one who has a tertiary qualification in Engineering (at least B Sc Engineering) of ( C Eng)

I have a B Sc in Mech Eng and until I could not afford the fees in 1988 I was MIMechE (C Eng)


I have two kids who are engineers and they would not have a clue... But I know a few guys that work on lathes and drilling and welding machinery who call themselves engineers but of course they are not

Correct, they are what are called ere artisans. Their skills are more practical than most Engineers but are still very skilled but in a very different to qualified Engineers. Some of us have done and 5 year apprenticeship than included practical skills to help design Engineers to design mechanical components that can be made economical

...who might. The guys in the brass founders probably would...

The proper guys who would know is any one with a degree in Metallurgy which is a domain and study of materials science and engineering. Vyv Cox is a very own Metallurgical Engineer.

The world exists on imprecision in language...

No terms like "Engineer: is used by people who need to bolster their ego and to con people they know more than they do to people who just don't understand the difference.
 
Your highlighted comment is the salient point generally referred to a bronze but in metallurgy terms is brass. Bronze can have other alloying elements for different properties of the final metal.

Bronze was first 3500 BC where brass only 500 BC. Bronze is a much better metal metal for swords as used in the bronze age as brass. brass would be too soft for that application.

Stick to your electrical installation work and leave the proper Engineering to proper qualified Engineers.

As usual, more insults than useful information. The materials used for manufacturing propellers contain various elements that are not found in "proper" brass. So they are not brass.
 
As far as I can make out from a few minutes googling, from a metallurgical point of view, brass is an alloy of copper & zinc, with or without other metals, such as lead and antimony in DZR brass. Bronze is an alloy of copper and tin, with or without additions, but with no zinc, so the "bronze" my prop is made of is actually a brass. What makes an alloy brass rather than bronze seems to be the presence of zinc. Take a bronze and add more than a trace of zinc and you've got a brass.
 
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