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Old 08-01-2013, 17:33   #76
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Re: Sea Cock Won't Open or Close

Just an FYI regarding bronze seacocks.

1. As far as I know all American "bronze" seacocks have been and are made of Copper alloy No. 836 (AKA - 85-5-5-5 copper/tin/zinc/lead, leaded red brass, composition bronze.) I've also seen it called red brass and gun metal. The reason for using this combination metal is it's very good resistance to corrosion and it's machinability. However, it does make it more malleable, which when hit can be deformed. If you want to know what the material really is, just ask if it's 85-5-5-5. Groco, Perko and Spartan all use 85-5-5-5. Perko uses a Celeron (phenolic) plastic ball which is well suited for marine use, corrosion resistant, minimal degradation in water (about 6%), far less degradation than any other plastic currently used for seacocks. Groco, I believe, uses either stainless steel or bronze balls, depending on the model.

2. Blake seacocks used to be made of bronze, but have for many years now been made from a corrosion resistant brass (copper 63%, zinc 37%). The reason it is considered corrosion resistant is the very careful way material is produced. The best I can understand is that the brass is annealed or super heated. It appears the heating process, that includes some chemicals, "dissolves" the zinc on the outer surfaces of the seacock/through-hull leaving only a hardened copper surface. Marine components that use this material should be stamped DZR (dezincification resistant) or CR (corrosion resistant).

3. I guess I'll stick with either Perko or Groco for ball valves or Spartan if I want an old fashion tapered cone seacock. We had Spartan seacocks on our Shannon and except for one, they worked fine. They just took a little more maintenance. The only thing I disliked about them was their female collared tailpieces. These were NPS threads and to seal so they don't vibrate loose not vibrate loose the collar had to be super tight, which made loosening a chore, especially in small places.

I hope this is of some help.
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Old 08-01-2013, 17:37   #77
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Re: Sea Cock Won't Open or Close

Quote:
Originally Posted by Jedg View Post
Just an FYI regarding bronze seacocks.

1. As far as I know all American "bronze" seacocks have been and are made of Copper alloy No. 836 (AKA - 85-5-5-5 copper/tin/zinc/lead, leaded red brass, composition bronze.) I've also seen it called red brass and gun metal. The reason for using this combination metal is it's very good resistance to corrosion and it's machinability. However, it does make it more malleable, which when hit can be deformed. If you want to know what the material really is, just ask if it's 85-5-5-5. Groco, Perko and Spartan all use 85-5-5-5. Perko uses a Celeron (phenolic) plastic ball which is well suited for marine use, corrosion resistant, minimal degradation in water (about 6%), far less degradation than any other plastic currently used for seacocks. Groco, I believe, uses either stainless steel or bronze balls, depending on the model.

2. Blake seacocks used to be made of bronze, but have for many years now been made from a corrosion resistant brass (copper 63%, zinc 37%). The reason it is considered corrosion resistant is the very careful way material is produced. The best I can understand is that the brass is annealed or super heated. It appears the heating process, that includes some chemicals, "dissolves" the zinc on the outer surfaces of the seacock/through-hull leaving only a hardened copper surface. Marine components that use this material should be stamped DZR (dezincification resistant) or CR (corrosion resistant).

3. I guess I'll stick with either Perko or Groco for ball valves or Spartan if I want an old fashion tapered cone seacock. We had Spartan seacocks on our Shannon and except for one, they worked fine. They just took a little more maintenance. The only thing I disliked about them was their female collared tailpieces. These were NPS threads and to seal so they don't vibrate loose not vibrate loose the collar had to be super tight, which made loosening a chore, especially in small places.

I hope this is of some help.
Thanks for the info. 85-5-5-5 is what used to be known as Manganese Bronze right?
Spartan used to advertise their stuff as silicon bronze..... dont know if it still is...
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Old 08-01-2013, 17:55   #78
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Re: Sea Cock Won't Open or Close

I talked to Spartan a few years ago. And they said they use 85-5-5-5 which goes by the bronze title of Composition Bronze. The lead apparently gives the metal a degree of softness that makes it reasonable to machine, hence, a more reasonable price.

Silicone Bronze is very ductile, it's 95% or so copper and only a little silicone, not sure it's what you would want for a seacock. I don't know how well it would machine. Manganese bronze???
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Old 08-01-2013, 18:01   #79
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Re: Sea Cock Won't Open or Close

Had you thought about careening the boat while you do the work ? Get some buddies to help you, buy a crate of beer and get the good lady to fire up the barbie for burgers for the lads when the jobs done. Tie a line off the top of the mast and haul her over sideways, when the seacock is clear of the water do the changeover, it's an ancient but fairly simple procedure. The other method would be to fill barrels of water and place on the deck and ballast the boat over. Before you got to those lengths have you tried a fine jet blowtorch on the valve, obviously you must take special care with the naked flame but often if there are disimmilar metals they will seize and a good bit of heat can 'crack' break, the seal. Beware of old water intake hoses as they can in some cases delaminate and starve the engine of water under full load but revert to normal on idle/low speed.
I hope this helps, Good Luck.
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Old 08-01-2013, 18:44   #80
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Re: Sea Cock Won't Open or Close

When it comes to careening a boat, I'd say I'm one of the best, as my avatar will attest.

Two for one. Both boats belonged to my wife and I.

Don't ask, just smile.
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Old 08-01-2013, 18:57   #81
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Re: Sea Cock Won't Open or Close

Jedg. It was intentional wasn't it ? :-) Great time to get the anti-fouling done though, before the tide comes back in.
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Old 08-01-2013, 19:18   #82
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Re: Sea Cock Won't Open or Close

Intentional it wasn't. Effective it was. We were rafted and the wind and tide were just right or wrong that early morning and the Shannon's keel caught as I was trying to get us into deeper water. It was on a Saturday and there were quite a few power boaters out. Many had no clue how to pass us, a few did and they were great at providing us a few extra beers while we waited.

Everything came back nice and easy. Just after we got off and were motoring away a TV news helicopter came by and circled the area. We speculated they were looking for a story.
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Old 08-01-2013, 19:32   #83
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Re: Sea Cock Won't Open or Close

Quote:
Originally Posted by Jedg View Post
I talked to Spartan a few years ago. And they said they use 85-5-5-5 which goes by the bronze title of Composition Bronze. The lead apparently gives the metal a degree of softness that makes it reasonable to machine, hence, a more reasonable price.

Silicone Bronze is very ductile, it's 95% or so copper and only a little silicone, not sure it's what you would want for a seacock. I don't know how well it would machine. Manganese bronze???
I was wrong about the Manganese... thought I deleted it immediately.. guess not!
Could have swore they said Silicon Bronze back when I bought a whole boat's worth of their stuff in the 80's. (stemhead fittings, portlites, seavalves etc) It was very warm gold colored as opposed to some of the Managanese I had cast for other stuff.
Si: 2.80-3.80%
Mn: 0.50-1.30%
Fe: 0.80% Max.
Zn: 1.50% Max.
Pb: 0.05% Max.
Cu: Balance

CuSi3Mn – UNS.C65500 Silicon Bronze Alloys, which is high strength, engineering alloys have excellent resistance to a wide range of corrosives, including fresh and salt water, most acids, alkalis, salts, and organic chemicals. However, they are not suitable for use with sulfides, nitric acid, acid chromates, or oxidizing salts such as ferric chloride. It has a combination of corrosion resistance, strength, resilience, and formability that makes them among the most widely used copper alloys.
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Old 08-01-2013, 20:10   #84
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Re: Sea Cock Won't Open or Close

I think I remember someone in the metals business telling me that you could cut 10 sets of 85-5-5-5 threads with one cutting blade and one set of silicone bronze threads. And the silicone bronze would take you longer to do.

From the sound of it the silicone bronze was great as a finished product but a bear to work with getting there.

Sounds like you know a lot more than I. My knowledge of bronze was simply as a way to compare plastic performance attributes with bronze. There are some plastics that compare favorably with bronze, (85-5-5-5), especially in water. Sadly, there not being used in the boating industry.
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Old 09-01-2013, 00:30   #85
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Re: Sea Cock Won't Open or Close

Nice one Jedg. At least you owned up ! I know quite a few who hop over the side and pretend to be scrubbing the bottom, (or in my case changing a prop !) we've all had snafu's and we can look back and have a chuckle over a beer or two and call it experience. Wisdom comes from a man who's run aground and learn't the hard way
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Old 09-01-2013, 10:27   #86
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Re: Sea Cock Won't Open or Close

Quote:
Originally Posted by Jedg View Post
I think I remember someone in the metals business telling me that you could cut 10 sets of 85-5-5-5 threads with one cutting blade and one set of silicone bronze threads. And the silicone bronze would take you longer to do.

From the sound of it the silicone bronze was great as a finished product but a bear to work with getting there.

Sounds like you know a lot more than I. My knowledge of bronze was simply as a way to compare plastic performance attributes with bronze. There are some plastics that compare favorably with bronze, (85-5-5-5), especially in water. Sadly, there not being used in the boating industry.
Nah, dont know too much about it. I come from aerospace and know more about stainless, inconel and titanium than bronze. Have used it though on some boats I built years ago.
I just looked up the machinability ratings. Most bronzes, including 85-5-5-5, silicon, manganese, red brass (naval bronze) are in the 30-60 range. Brasses are more like 70-100 range. Leaded Silicon and Aluminum bronze is in the 60 range so a little better.
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