Bismuth solder Sn43/Bi57 - Page 1
Forum section: electronics / general

author: Free_WiFi
author_rank: Regular Contributor
timestamp: February 20, 2019, 12:24:15 pm
content: Hello people!I'm doing this thread to ask you,which Sn43/Bi57 solder wire brand do you know.Basically i already use the genuine Cynel 60/40 and now i want to switch to another one,because of health reasons ....Thanks to all for advices etc ..

author: PedroDaGr8
author_rank: Super Contributor
timestamp: February 20, 2019, 04:51:12 pm
content: As a chemist with a background in heavy metals, there are no common health reasons to avoid lead-based solders. Lead does not volatilize during soldering, only the flux; if you wash your hands after soldering you have eliminated essentially all routes of ingestion. In fact, as lead-free solders often require more aggressive flux (which DOES volatilize) you can actually be making a less healthy substitute.The reasons for switching to lead-free solders is entirely environmental. As in the environment lead can leach out as lead salts, which are MARKEDLY more toxic than metallic lead.

author: Free_WiFi
author_rank: Regular Contributor
timestamp: February 20, 2019, 08:05:14 pm
content: Im using the flux in the picture.

author: wraper
author_rank: Unknown
timestamp: February 20, 2019, 08:20:17 pm
content: Quote from: Free_WiFi on February 20, 2019, 08:05:14 pmThe right place for it would be trash bin.

author: Gyro
author_rank: Super Contributor
timestamp: February 20, 2019, 08:21:13 pm
content: That is presumably Rosin (and a nice lump at that). Rosin fumes are going to cause you far more problems than physical contact with metallic lead, although as PedroDaGr8 points out, it's a lot less nasty than the flux in lead-free solders.From Wikipedia:QuoteGood ventilation and sensible hand washing are the keys to safe soldering.

author: wraper
author_rank: Unknown
timestamp: February 20, 2019, 08:23:14 pm
content: Quote from: Gyro on February 20, 2019, 08:21:13 pmJust good ventilation is not enough. Fume extraction is essential for avoiding breathing flux fumes while soldering.

author: Gyro
author_rank: Super Contributor
timestamp: February 20, 2019, 08:34:00 pm
content: Ideally yes, but more difficult to arrange in a hobby situation. A small fan blowing the fumes away from your nose and towards an open window is better than nothing.P.S. A useful reference on fume extraction...http://www.hse.gov.uk/pubns/indg249.pdf

author: Ian.M
author_rank: Super Contributor
timestamp: February 20, 2019, 09:12:34 pm
content: Knocking a lump off that chunk of rosin, pulverising it and dissolving it in just enough 95% alcohol (denatured ethanol or IPA) to get a liquid with the consistency of runny syrup, that can be applied to the work in a controlled fashion using a small brush bottle would be a good way to reduce rosin fume exposure, as sticking the soldering iron bit in the rosin to melt some for use causes excessive and unnecessary fuming.Alternatively, just stick a flux pen on your next parts order. Any western brand of RMA flux from a reputable distributor will be fine, and will be less messy and more effectvie than making your own unactivated liquid rosin flux.

author: Gyro
author_rank: Super Contributor
timestamp: February 20, 2019, 09:34:22 pm
content: Another thought. Is unactivated rosin flux going to be effective at the low melting point of Sn43/Bi57 (139'C)?