Someone asked me the other day if copper or aluminum was a better heat sink.
I thought copper was better at moving heat through metal, but aluminum was better at coupling with the air.
Well I did a test, 2 reasonably new 7875's with 2.4a drivers from DTR both in MX-900's with Budget Beams heat sinks
One has this 2 x 2 bar stock that was going to be a triple, the other I drilled and used some self tappers to attach a 1.5 x 2 x 1/4 inch copper plate and I'll be damned if this copper plate didn't boost duty cycle by 300%, about the same as the big aluminum bar.
Without the additions the BB sink gets warm in 2 minutes, with the additions they both are not really warm until 5-6 minutes, maybe a bit more, anyway I was surprised how well the copper dissipates heat into the air, it also seems to hold more heat as it has a higher density so to do a fair test I would need to record cooling time. Still the copper surprised me, I have used it before but usually internally, comparing like this I was surprised.
When I cut leaves from my windows the stems are always the hardest part to burn through, so I have a laser in each hand, It's fun putting one little focused bar on top of the other, more power is more fun, anyway I expected the copper would get hot quickly, but it works a lot better than I expected.
Now I'm thinking about a big copper finned unit...hmm :thinking:
