Galvanic series - bronze and silver solder?

[The Bigfella]

I've got an issue with the plumbing for the head on Grantala.

I brought in some 90 degree bronze fittings which weren't what was depicted in the online catalogue - ie they were supposed to take two sizes of hose, but turned up as a single size fitting. At least that supplier has amended their catalogue as a result - but, I still have the problem of a couple of skin fittings that need 90 degree elbows that reduce from 1.25 and 1.5 inch pipes down to 1 inch hose. Oh - and I refuse to have plastic fittings on any circuit that will be left open for any length of time.

So - I need to make my own bronze fittings up - from the supplied fittings and some 1" hose tails. The larger, 1.5" fitting looks large enough to just tap for the hose fitting, but the 1.25" fitting will need to be either brazed or as someone else suggested, silver-soldered. My welding supply shop couldn't help with bronze brazing rods and I'm a bit concerned about galvanic issues with the silver solder. Silver and lead are both a bit more noble than bronze - but it doesn't appear to be too far apart.

Do we have any galvanic series experts here who could add to the discussion? Calder, incidentally, hasn't got silver solder in the table in his book, but I did find it mentioned online elsewhere - at about the Monel level.

Thanks
Ian

[Paul Fitzgerald]

Why not braze it with some MAPP?

[George Ray]

http://www.csudh.edu/oliver/chemdata/alloys.htm

80Ag, 13Cu, 6.8Zn Silver solder, hard


*****************************************


http://www.corrosion-doctors.org/Def...nic-series.htm

Active (Anodic)

1. Magnesium
2. Mg alloy AZ-31B
3. Mg alloy HK-31A
4. Zinc (hot-dip, die cast, or plated)
5. Beryllium (hot pressed)
6. Al 7072 clad on 7075
7. Al 2014-T3
8. Al 1160-H14
9. Al 7079-T6
10. Cadmium (plated)
11. Uranium
12. Al 218 (die cast)
13. Al 5052-0
14. Al 5052-H12
15. Al 5456-0, H353
16. Al 5052-H32
17. Al 1100-0
18. Al 3003-H25
19. Al 6061-T6
20. Al A360 (die cast)
21. Al 7075-T6
22. Al 6061-0
23. Indium
24. Al 2014-0
25. Al 2024-T4
26. Al 5052-H16
27. Tin (plated)
28. Stainless steel 430 (active)
29. Lead
30. Steel 1010
31. Iron (cast)
32. Stainless steel 410 (active)
33. Copper (plated, cast, or wrought)
34. Nickel (plated)
35. Chromium (Plated)
36. Tantalum
37. AM350 (active)
38. Stainless steel 310 (active)
39. Stainless steel 301 (active)
40. Stainless steel 304 (active)
41. Stainless steel 430 (active)
42. Stainless steel 410 (active)
43. Stainless steel 17-7PH (active)
44. Tungsten
45. Niobium (columbium) 1% Zr
46. Brass, Yellow, 268
47. Uranium 8% Mo
48. Brass, Naval, 464
49. Yellow Brass
50. Muntz Metal 280
51. Brass (plated)
52. Nickel-silver (18% Ni)
53. Stainless steel 316L (active)
54. Bronze 220
55. Copper 110
56. Red Brass
57. Stainless steel 347 (active)
58. Molybdenum, Commercial pure
59. Copper-nickel 715
60. Admiralty brass
61. Stainless steel 202 (active)
62. Bronze, Phosphor 534 (B-1)
63. Monel 400
64. Stainless steel 201 (active)
65. Carpenter 20 (active)
66. Stainless steel 321 (active)
67. Stainless steel 316 (active)
68. Stainless steel 309 (active)
69. Stainless steel 17-7PH (passive)
70. Silicone Bronze 655
71. Stainless steel 304 (passive)
72. Stainless steel 301 (passive)
73. Stainless steel 321 (passive)
74. Stainless steel 201 (passive)
75. Stainless steel 286 (passive)
76. Stainless steel 316L (passive)
77. AM355 (active)
78. Stainless steel 202 (passive)
79. Carpenter 20 (passive)
80. AM355 (passive)
81. A286 (passive)
82. Titanium 5A1, 2.5 Sn
83. Titanium 13V, 11Cr, 3Al (annealed)
84. Titanium 6Al, 4V (solution treated and aged)
85. Titanium 6Al, 4V (anneal)
86. Titanium 8Mn
87. Titanium 13V, 11Cr 3Al (solution heat treated and aged)
88. Titanium 75A
89. AM350 (passive)
90. Silver
91. Gold
92. Graphite

End - Noble (Less Active, Cathodic)

[The Bigfella]

Paul - the issue isn't the gas - I have oxy acetylene at home, rather a concern about a joint failure due to corrosion.

George - that's interesting, as they don't list silver solder as such in that list. This lot do - and its much lower than straight silver:

MAGNESIUM
MAGNESIUM ALLOYS
ZINC
ALUMINUM 5052, 3004, 3003, 1100, 6053
CADMIUM
ALUMINUM 2117, 2017, 2024
MILD STEEL (1018), WROUGHT IRON
CAST IRON, LOW ALLOY HIGH STRENGTH STEEL
CHROME IRON (ACTIVE)
STAINLESS STEEL, 430 SERIES (ACTIVE)
302, 303, 321, 347, 410,416, STAINLESS STEEL (ACTIVE)
NI - RESIST
316, 317, STAINLESS STEEL (ACTIVE)
CARPENTER 20CB-3 STAINLESS (ACTIVE)
ALUMINUM BRONZE (CA 687)
HASTELLOY C (ACTIVE) INCONEL 625 (ACTIVE),
TITANIUM (ACTIVE)
LEAD - TIN SOLDERS
LEAD
TIN
INCONEL 600 (ACTIVE)
NICKEL (ACTIVE)
60 NI-15 CR (ACTIVE)
80 NI-20 CR (ACTIVE)
HASTELLOY B (ACTIVE)
BRASSES
COPPER (CA102)
MANGANESE BRONZE (CA 675), TIN BRONZE (CA903, 905)
SILICONE BRONZE
NICKEL SILVER
COPPER - NICKEL ALLOY 90-10
COPPER - NICKEL ALLOY 80-20
430 STAINLESS STEEL
NICKEL, ALUMINUM, BRONZE (CA 630, 632)
MONEL 400, K500
SILVER SOLDER
NICKEL (PASSIVE)
60 NI- 15 CR (PASSIVE)
INCONEL 600 (PASSIVE)
80 NI- 20 CR (PASSIVE)
CHROME IRON (PASSIVE)
302, 303, 304, 321, 347, STAINLESS STEEL (PASSIVE)
316, 317, STAINLESS STEEL (PASSIVE)
CARPENTER 20 CB-3 STAINLESS (PASSIVE),
INCOLOY 825NICKEL - MOLYBDEUM - CHROMIUM -
IRON ALLOY (PASSIVE)
SILVER
TITANIUM (PASS.) HASTELLOY C & C276 (PASSIVE),
INCONEL 625(PASS.)
GRAPHITE
ZIRCONIUM
GOLD
PLATINUM


From http://www.prevco.com/Reference/Galvanic.htm

That said, I'm told to use a specific "Blue tip" Silver solder, not that "plumber's junk". I also just noticed there's a "Nickel Silver" in there that is pretty close to bronze.

Oh, wouldn't it be nice if the damned fitting had been what it was supposed to have been!

[donald branscom]

I've got an issue with the plumbing for the head on Grantala.

I brought in some 90 degree bronze fittings which weren't what was depicted in the online catalogue - ie they were supposed to take two sizes of hose, but turned up as a single size fitting. At least that supplier has amended their catalogue as a result - but, I still have the problem of a couple of skin fittings that need 90 degree elbows that reduce from 1.25 and 1.5 inch pipes down to 1 inch hose. Oh - and I refuse to have plastic fittings on any circuit that will be left open for any length of time.

So - I need to make my own bronze fittings up - from the supplied fittings and some 1" hose tails. The larger, 1.5" fitting looks large enough to just tap for the hose fitting, but the 1.25" fitting will need to be either brazed or as someone else suggested, silver-soldered. My welding supply shop couldn't help with bronze brazing rods and I'm a bit concerned about galvanic issues with the silver solder. Silver and lead are both a bit more noble than bronze - but it doesn't appear to be too far apart.

Do we have any galvanic series experts here who could add to the discussion? Calder, incidentally, hasn't got silver solder in the table in his book, but I did find it mentioned online elsewhere - at about the Monel level.

Thanks
Ian

One solution would be to weld with silicon bronze filler wire - TIG process. I would not braze that part.

[pipefitter]

Surely, there has to be another way to adapt it without welding. We come across this different size hose issue alot when setting up livewells/baitwells in alot of the boats we work on.

It would be better if they would just standardize the stuff to begin with.

[The Bigfella]

Surely, there has to be another way to adapt it without welding. We come across this different size hose issue alot when setting up livewells/baitwells in alot of the boats we work on.

It would be better if they would just standardize the stuff to begin with.

I totally agree with you there, but this is an old boat and I've got to deal with a couple of oversized through-hulls here. I may get around to replacing that plank some year - athough, I think these are on different planks ........

I have got it connected up - but with plastic fittings - and I hate them with a vengeance.

Ian

[jverl]

What I find very curious is that even experts can not agree on the correct sequence. Note Monel 400 and Silicon Bronze (655):
"63. Monel 400
64. Stainless steel 201 (active)
65. Carpenter 20 (active)
66. Stainless steel 321 (active)
67. Stainless steel 316 (active)
68. Stainless steel 309 (active)
69. Stainless steel 17-7PH (passive)
70. Silicone Bronze 655" and
"SILICONE BRONZE
NICKEL SILVER
COPPER - NICKEL ALLOY 90-10
COPPER - NICKEL ALLOY 80-20
430 STAINLESS STEEL
NICKEL, ALUMINUM, BRONZE (CA 630, 632)
MONEL 400, K500".
What can we normal mortals decide then?
Is there a definitive list that everyone agrees to?

John

[The Bigfella]

The difference may be due to the testing medium perhaps? ie seawater - or an alternative solution.

[George Ray]

Is there a definitive list that everyone agrees to?

Get: (A) bronze from the head, (B) New bronze tailpipe, (C) stick of hard silver solder, (D) Sea Water, (E) Digital Volt Meter.

Immerse and measure the developed potential between AB, AC, BC.

Report back.

[The Bigfella]

Get: (A) bronze from the head, (B) New bronze tailpipe, (C) stick of hard silver solder, (D) Sea Water, (E) Digital Volt Meter.

Immerse and measure the developed potential between AB, AC, BC.

Report back.

It has barely stopped raining here for weeks - my boats in "fresh" rather brown water at the moment - and given that there are a million or so cats and dogs not far upstream, I'm not inclined to taste it to check its salinity at the moment! Good idea though - thanks

[Jay Greer]

All I can say is that I have had good luck with, made up, above water fittings that I have silver soldered. How ever, I once fastened a silver coin to a mast heel with a copper sheathing clout nail from "Cutty Sark." After one season, the nail was eaten away! The mast heel was not immersed, just in a damp area.
Jay

[donald branscom]

What I find very curious is that even experts can not agree on the correct sequence. Note Monel 400 and Silicon Bronze (655):
"63. Monel 400
64. Stainless steel 201 (active)
65. Carpenter 20 (active)
66. Stainless steel 321 (active)
67. Stainless steel 316 (active)
68. Stainless steel 309 (active)
69. Stainless steel 17-7PH (passive)
70. Silicone Bronze 655" and
"SILICONE BRONZE
NICKEL SILVER
COPPER - NICKEL ALLOY 90-10
COPPER - NICKEL ALLOY 80-20
430 STAINLESS STEEL
NICKEL, ALUMINUM, BRONZE (CA 630, 632)
MONEL 400, K500".
What can we normal mortals decide then?
Is there a definitive list that everyone agrees to?
John

Stainless (passive) means above the waterline.
17-PH would be a propshaft . Part of it below the water and part of it above the waterline. A very special case.

Stainless 321- come on what are the chances? Especially below the water?

309 stainless. (active) Why would it be used below the water?
It is used as a filler for joining steel to stainless. Like welding a stainless chain plate to a steel hull.

The point is that as long as there is not a 30 point difference i would not worry. Keep it as low as possible. But remember if the metal is underwater and moving at 6 knots or more corrosion would be 30% higher.

Stainless and bronze work ok together and steel and aluminum work together above the water.

NEVER let a copper penny get in the bilge of a steel boat and dropping a dime could eat its way thru a piece of 3/16 steel in about a year.

[Canoeyawl]

It seems to me that the only galvanic part of the fitting that would be exposed to electrolyte is the very thin edge of the solder joint.
If that is true any corrosion or electrolysis should be very local i.e. at the .003” or .004" solder lines and of little concern.
The old “Gold Platers” had much bigger problems, Eh?
Or - I wouldn’t worry about it.