A heatsink on a Zero is a waste of effort because it's next to impossible to get it running hot. A heatsink on a 3B+ may not be needed as the termal conduction of the CPU package and circuit board are an order of magnitude better than earlier models.
Microprocessor, Raspberry Pi & Arduino Hacker
Mainframe database troubleshooter
2012-18: 1B*5, 2B*2, B+, A+, Z, ZW, 3Bs*3, 3B+
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