Aluminum vs Copper Heatsinking

Do any of you guys have experience with both aluminum and copper heatsinks, and can tell me the difference between them in terms of effect on heat dissipation (duty cycle) in a 9mm 445nm laser (any laser really but the 3W+ 445nm's in particular) and such? Thanks

My DominatoR has a copper heat sink in it, I can tell you the cost difference, about $100. I tend to notice copper heat sinked lasers feel warm sooner than aluminum ones, indicating the heat is drawn away faster. though none of my aluminum heat sinks are anywhere near the size of the DominatoR. I think copper has better heat transfer, but lower capacity. copper tarnishes, aluminum doesn't. copper is lots heavier. I'd go with copper, especially on expensive diodes that heat quickly, like the 9mm. you want that heat sucked up as fast as possible.

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