Solder smoke physics - Page 1
Forum section: electronics / general

author: Dajgoro
author_rank: Frequent Contributor
timestamp: August 13, 2018, 12:18:45 am
content: Hi,When soldering, the solder smoke tends to go toward the face.I always though it was because of a draft, but then I tested it by moving away a bit and the smoke went straight up.So I took a box, placed it next to the soldering iron, and the smoke would always go toward the box no matter where I put it as long its close and big enough.Then I made another test, took a box bit bigger than my head and placed it close to the soldering iron, and suddenly the solder smoke started going always toward the box.What sort of phenomenon is this?Are some sort of air vortices created from the hot air at the obstacle edges that keep pulling the hot air in the same direction?

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 13, 2018, 12:52:55 am
content: Moving air tends to "stick" to surfaces. I think that what you're seeing is the coandă effect, which describes this phenomena.https://wikipedia.org/wiki/Coandă_effect

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 13, 2018, 12:54:29 am
content: Your head is hot (brain is powerful) so you have rising air around you. I suppose this is the same reason shower curtains move when you take a hot shower.

author: mariush
author_rank: Super Contributor
timestamp: August 13, 2018, 01:01:19 am
content: or a side effect of your breath .. like sucking air in then holding your breath (maybe unconsciously) so that you don't breathe in smokeor just pulling solder iron towards you when done could create a current of air. or you lifting your head away from work piece, or straightening your body when done....

author: Dajgoro
author_rank: Frequent Contributor
timestamp: August 13, 2018, 03:09:06 am
content: QuoteIts not that, when I solder I either don't breathe at all or I slowly exhale to blow off the smoke from my face.The trick with the box works when I'm not close.The Coandă effect on the other hand might be the reason.But then shouldn't the smoke be divided into two streams, why then does it only pick one side?

author: abraxa
author_rank: Frequent Contributor
timestamp: August 13, 2018, 02:26:08 pm
content: Maybe it's the same effect observable at camp fires (or outdoor grills)?https://www.quora.com/Why-does-the-smoke-from-a-fire-always-seem-to-follow-me

author: MadTux
author_rank: Frequent Contributor
timestamp: August 13, 2018, 02:33:25 pm
content: Just put a couple of big old computer fans on the table in front of where you're soldering. Air gets drawn away from your face and the fumes dispersed and diluted in the large volume of air inside your room.

author: Pinkus
author_rank: Frequent Contributor
timestamp: August 13, 2018, 02:55:27 pm
content: Quote from: MadTux on August 13, 2018, 02:33:25 pm... and the hazardous microscopic particles will become breathed then later...thus: not a good idea! Get a fume extractor with a decent filter (better two or three different ones in a row). Probably everything below 100 Euros will be just crap.

author: Dajgoro
author_rank: Frequent Contributor
timestamp: August 13, 2018, 06:53:56 pm
content: Quote from: Pinkus on August 13, 2018, 02:55:27 pmI have one already, but I don't use it always. Solder smoke hazards aside, I'm curious just about the physics side of the phenomenon.

author: innkeeper
author_rank: Unknown
timestamp: August 13, 2018, 07:16:40 pm
content: breathe in your lead and rosin the easy way the new rosin and lead VAPE flavor!WARNING: Not intended as a replacement for soldering iron.

author: Dajgoro
author_rank: Frequent Contributor
timestamp: August 13, 2018, 11:06:19 pm
content: Quote from: innkeeper on August 13, 2018, 07:16:40 pm

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 14, 2018, 06:34:46 am
content: Quote from: Dajgoro on August 13, 2018, 03:09:06 amI don't think moving air likes to be easily split in two like that.