Galvanic corrosion , Aluminum and Copper press fit.

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justahoby
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Galvanic corrosion , Aluminum and Copper press fit.

Post by justahoby » Sat Feb 15, 2014 7:09 pm

I know there is A reaction between aluminum and copper, but wonder about in a press fit ( interference fit)Does the type of aluminum or aluminum alloy in a Suzuki head ( Car) matter? If it is fine with such an alloy, what about in the presence of water ? Antifreeze ? Devcon? I may use a different material .. Or scrap the idea.
As I'm approaching 40,I still think I'm 20. What the hell is wrong with me?

Dan Timberlake
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Re: Galvanic corrosion , Aluminum and Copper press fit.

Post by Dan Timberlake » Sun Feb 16, 2014 6:15 pm

Most coolant/antifreeze contains wording like this -
"This patented formula provides a high degree of performance durability and carefully balanced protection against temperature extremes and rust and corrosion of all cooling system metals, including aluminum."
Stolen from here -
http://prestone.com/products/antifreeze ... t_region=1

It is possible if extreme pockets of stagnant coolant can form the sacrificial anti-corrosion additives are depleted and local corrosion can be pretty severe. If the coolant is several years old then the additives are getting low anyhow, so local pockets can form more easily. Like at the steel/mls headgasket or solder joints in the radiator and heater core.

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Re: Galvanic corrosion , Aluminum and Copper press fit.

Post by jsgarage » Sat Feb 22, 2014 11:50 pm

Hobby, there is no galvanic corrosion without moisture. So a nice tight press fit of dissimilar metals should not corrode at all in the contact area. On the outside edge, maybe. A small bead of epoxy around the sides of the joint (if accessible) could eliminate edge corrosion too.

justahoby
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Re: Galvanic corrosion , Aluminum and Copper press fit.

Post by justahoby » Sun Feb 23, 2014 1:22 am

jsgarage wrote:Hobby, there is no galvanic corrosion without moisture. So a nice tight press fit of dissimilar metals should not corrode at all in the contact area. On the outside edge, maybe. A small bead of epoxy around the sides of the joint (if accessible) could eliminate edge corrosion too.
Thanks ,that's what I was thinking , and if I get into coolant areas I am thinking I may use a diesel antifreeze with the stuff to prevent any electrolysis .
As I'm approaching 40,I still think I'm 20. What the hell is wrong with me?

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Re: Galvanic corrosion , Aluminum and Copper press fit.

Post by 4sfed » Sun Feb 23, 2014 9:14 pm

jsgarage wrote:Hobby, there is no galvanic corrosion without moisture. So a nice tight press fit of dissimilar metals should not corrode at all in the contact area. On the outside edge, maybe. A small bead of epoxy around the sides of the joint (if accessible) could eliminate edge corrosion too.
Remember that Loctite is an anaerobic epoxy . . .

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Re: Galvanic corrosion , Aluminum and Copper press fit.

Post by underhead valve » Sat Apr 26, 2014 2:04 am

Mercedes used copper intake guides in aluminum heads for many years, I have scrapped over 60 lbs of copper guides ---they did wear fast, have never seen any corrosion at the guide/head interface even on heads that there was long term gasket problems that ate the head away from the valve seat.
Most got replaced with bronze guides that lasted twice as long. --in the same application that the copper guides wore out at 60k, bronze was good at 100k

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