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Solar Mike · 06-13-11, 03:15 AM

Hi
I have made many types of solar hot water collectors over the past 5 years or so, generally I have found its easier to use thin copper foil (0.25mm thick) fins soldered to the risers than using aluminum. Even though AL. is cheaper its long term reliability in this application is suspect (20 years +), ie the different rates of expansion between the differing metals will eventually work the fins loose, or cause corrosion failure if they ever come in direct contact. Copper foil is not that expensive, $26 per Kg here in NZ if purchased in a 50 Kg roll, will make many panels, go halves with someone else.

Cheers
Mike (NZ)

06-13-11, 03:15 AM	#8
Solar Mike Helper EcoRenovator Join Date: Apr 2010 Location: Wellington, New Zealand Posts: 61 Thanks: 0 Thanked 6 Times in 5 Posts	Hi I have made many types of solar hot water collectors over the past 5 years or so, generally I have found its easier to use thin copper foil (0.25mm thick) fins soldered to the risers than using aluminum. Even though AL. is cheaper its long term reliability in this application is suspect (20 years +), ie the different rates of expansion between the differing metals will eventually work the fins loose, or cause corrosion failure if they ever come in direct contact. Copper foil is not that expensive, $26 per Kg here in NZ if purchased in a 50 Kg roll, will make many panels, go halves with someone else. Cheers Mike (NZ)