Bronze Pipe Nipples

[Maine Sail]

I know this has come up before and no one has been able to find a source of real bronze, not red brass, pipe nipples.

I stumbled across a Groco catalog and lo and behold they DO make a bronze pipe nipple!!

Groco Bronze PN Series Pipe Nipples (LINK)

 

[Ross]

What alloy?
http://www.anchorbronze.com/

 

[Maine Sail]

What alloy?
http://www.anchorbronze.com/

All they say is that it is the same as their seacocks and galvanically compatible. Their seacocks, thru-hulls and other bronze is very, very resistant to corrosion. I have yet to have a Groco fitting suffer from any sort of galvanic degredation.

We know red brass is resistant to galvanic corrosion but has a much higher zinc content, about 15%, than does marine grade bronze so they technically are not galvanically compatible. Most pipe nipples you can buy at chandleries are red or yellow brass. While red is decent it's not ideal..

 

[Ross]

I have always been amused by the confusion in naming copper alloys Naval bronze is by some definitions a brass. As best as I can learn if its primary alloying metal is zinc it should be called a brass. If zinc is a minor alloy and there are other metals used then it is a bronze. I would trust Groco or Buck Algonquin to get it right.

 

[RAD]

My dock neighbor went through this last summer and he needed a 2" or 1-1/2" coupling,so I offered to get one at a big plumbing supply and could only find a brass one but believe or not one day shortly after the purchase I noticed in the plumbing section of West Marine they had bronze couplings so I told my neighbor and he bought it and changed out the brass one

 

[Maine Sail]

I have always been amuzed by the confusion in naming copper alloys Naval bronze is by some diffinitions a brass. As best as I can learn if its primary alloying metal is zinc it should be called a brass. If zinc is a minor alloy and there are other metals used then it is a bronze. I would trust Groco or Buck Algonquin to get it right.

For instance Manganese Bronze and Tobin Bronze are very high zinc content but are still considered a bronze?

This is why you see bronze prop shafts, usually made of tobin bronze & about 40% zinc, with dezincification and props, often made of manganese bronze, with dezincification. Nibral Nickel/bronze/aluminum has very little to no zinc but few sailboat props are made from Nibral and it is usually reserved for higher horsepower props. More expensive folders like Flex-O-Fold are made from Nibral but the standard Michigan Wheel "MP sailor props" are generally manganese bronze unless special ordered in nibral.

 

[sailingdog]

The major problem is finding someone who stocks the bronze nipples at a reasonable price.

 

[Maine Sail]

The major problem is finding someone who stocks the bronze nipples at a reasonable price.

They can be ordered from any Groco dealer and the issue is NOT price. Cut a corner and mix brass and bronze and it could cost you a lot more than the price of a nipple!!

This is what can happen when mixing a brass hose barb and a bronze elbow. Note the pinkish dezincification of the brass where it broke..

 

[sailingdog]

Maine—

You know I would never advocate mixing metals or cutting corners.

 

[Ross]

Domestic plumbing often has chrome plated yellow brass nipples threaded into copper piping and if the water isn't neutral they come apart. I have picked the remains of the threads out of a female adapter. lift an end and unwind them like a piece of wire.

 

[Hermit Scott]

What happens to copper in sea water? Why is it not used more? Also I have a bunch of fittings on old seacocks that came in a box of parts, how do I tell if they are bronze or brass?

 

[sailingdog]

If the copper is connected to more or less noble metals, it creates a galvanic cell and depending on the nobility of the metals involved, bad things happen. Aluminum and brasses are generally fairly low on the scale, bronze, passivated stainless steels, titanium are fairly high on the scale.

What happens to copper in sea water? Why is it not used more? Also I have a bunch of fittings on old seacocks that came in a box of parts, how do I tell if they are bronze or brass?

 

[Hermit Scott]

Bronze or Brass?

Here are two identical hose barbs. I cleaned one up and left one how it came out.

 

[sailingdog]

Hose barbs on plastic or rubber hose isn't the problem. It is when metal-to-metal contact is present, like using a copper or brass pipe nipple with a bronze fitting. The fact that the two metals are in contact and one is more or less noble than the other is what causes the problem—especially if the fluid they're carrying is salt water.

Here are two identical hose barbs. I cleaned one up and left one how it came out.