metals and galvanic corrosion

[HJALBERT]

I've heard tell of copper being unacceptable for heat exchanger components exposed to V.O.), yet alot of people do it (myself included). There is alot of talk about what lasts and what doesnt, as far as hoses and the like. I was wondering what the thoughts of other people were on galvanic corrosion with these systems. Another question I have, If aluminum is preferred, then why are brass fittings used instead of aluminum (obvious availibilty) or carbon steel or iron? thanks for the input, John

[Todd T]

Its not so much galvanic reaction (as in metal to metal contact) as the acidic nature of the veggie.

Veggie does have some very mild corrosive action on brass/copper. On the outside of a brass fitting you'll see green from corrosion. This is from incidental contact. But on the inside of that fitting where the veggie is in full contact the brass will be clean.

Some feel the corrosion potential of veggie is related to how much water is present. I feel the FFA levels will have a lot to do with corrosion. This gives more incentive to explore the baking soda wash.

Todd