Sorry for the general nature of this question. But I have always asked myself what makes solder fumes smell of incense.


closed as primarily opinion-based by Leon Heller, PeterJ, Enric Blanco, Dmitry Grigoryev, Voltage Spike Jul 5 '17 at 15:31

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    \$\begingroup\$ Burning flux. It's a mild respiratory irritant. elexp.com/Images/Health_Hazards.PDF \$\endgroup\$ – pjc50 Jul 4 '17 at 14:26
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    \$\begingroup\$ Mainly to get hippies interested in electronics. \$\endgroup\$ – Andy aka Jul 4 '17 at 14:39

"Resin core" is incorrect, it is "Rosin core", and rosin is different, albeit from the same source. Pine tree resin is heated to remove the volatile elements in it such as turpentine, leaving behind a solid brittle substance called rosin. That rosin will melt again when heated but is difficult to burn and it contains a mild acid. When it melts, the acid etches the metal surfaces so that the solder sticks. If solder had resin inside, it would result in flames when you used it and leave behind carbon deposits.

  • \$\begingroup\$ Thanks for the clarification. I use rosin frequently as a violin player, but I wasn't sure about the different technical terms for it. \$\endgroup\$ – Quasilattice Jul 4 '17 at 21:27

Assuming that you use the standard spools of solder, look closely at the label. It will say "resin-core solder", or something like it. The solder actually contains a core of resin which acts as flux to make a good solder joint possible. It is the hot resin which you smell.

  • \$\begingroup\$ Thanks that makes sense, thank you. Incense is just another type of resin. \$\endgroup\$ – Quasilattice Jul 4 '17 at 14:26
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    \$\begingroup\$ @Quasilattice - If you have a good magnifier, take a bit of solder and slice the end off with a razor blade or very sharp knife. You will be able to see the rosin core. \$\endgroup\$ – WhatRoughBeast Jul 4 '17 at 14:37
  • \$\begingroup\$ Why the downvotes? \$\endgroup\$ – Quasilattice Jul 5 '17 at 13:27

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