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Rick,
I have included below a letter posted to the LML several years ago. You may find it helpful.
On my boat I have started using a lubricant called Tef-Gel (http://www.tefgel.com/tef_gelm_information.htm). This lubricant is supposed to stop corrosion between dissimilar metals (like mast aluminum and stainless steel screws). A google search for Tef-Gel will give you the suppliers.
Lorn
On: Mon Apr 15 16:31:24 2002
From: "Ted Stanley" <direct@vineyard.net>
Regarding corrosion and the results of using various materials next to one another I thought I'd pass on the listing below which should be of interest to builders.
Avoid having materials next to each other that are widely separated on the listing below. Note too that the material at the corroded end of the chart will do just that, corrode, when placed next to a material at the other end of the chart.
Naturally anything that acts as an electrolyte only aggravates the process.
When I was in A&P school I had to build an aluminum wing rib as a project. As an experiment I asked a commercial fisherman friend of mine to toss it in the bow of his boat for a week. The result was almost no corrosion. I took it back and riveted a copper penny to it and sent it back to the bow of the boat. A week later the rib was badly corroded, particularly between the penny and the aluminum.
Hope everyone finds this useful.
Ted Stanley - A&P-IA
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GALVANIC SERIES OF METALS AND ALLOYS
CORRODED END ( ANODIC OR LEAST NOBLE)
MAGNESIUM -2.375
MAGNESIUM ALLOYS
ZINC -0.7628
ALUMINUM 5052, 3004, 3003, 1100, 6053
CADMIUM
ALUMINUM 2117, 2017, 2024
MILD STEEL (1018), WROUGHT IRON
CAST IRON, LOW ALLOY HIGH STRENGTH STEEL -0.036
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 +0.15
LEAD
TIN
INCONEL 600 (ACTIVE)
NICKEL (ACTIVE)
60 NI-15 CR (ACTIVE)
80 NI-20 CR (ACTIVE)
HASTELLOY B (ACTIVE)
BRASSES +0.522
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 +0.7996
TITANIUM (PASS.) HASTELLOY C & C276 (PASSIVE), INCONEL 625(PASS.)
GRAPHITE +0.8
ZIRCONIUM
GOLD +1.68
PLATINUM
PROTECTED END (CATHODIC OR MOST NOBLE)=20
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The Mc Nally Institute
1986 S. Belcher Rd. Clearwater, Florida 33764
Phone 727 535 6450 Fax 727 535 8150
E mail mcnally@earthlink.net
http://www.mcnallyinstitute.com/Charts/galvanic-series.html</x-rich>
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