Flux and health issues - Page 1
Forum section: electronics / general

author: Kuro
author_rank: Regular Contributor
timestamp: September 01, 2016, 06:16:17 pm
content: Since I'm starting again with electronics and soldering after 40 years, I figured I'd better start over with the basics and watched Dave's video soldering tutorials (great stuff!). It was rather interesting that he warned that the vapours from soldering do not contain lead, but it's the flux vapour that is a health issue.I don't have a professional filtered air absorbtion system, I just make sure the room is ventilated. Nevertheless, I already have some respiratory problems, so I looked into this further. Wikipedia.de revealed that the often mentioned Kolophonium (German) is basically Rosin, and can cause astma and other issues. It also stated that Rosin is no longer used much, but replaced with alcohol or water soluble alternatives. For me, the possible health issues are a potential problem, and it's better to prevent than to cure.Here in Belgium, electronics stores have mostly gone belly-up, so I buy stuff from Amazon Germany. There isn't as much choice of types and brands of soldering stuff as I expected, and when I looked up the soldering wick from Spirig (a good Swiss company, I'm told) I found the flux used is kolophonium. And just about all solder with flux core has rosin. I looked at the other electronic stores that I am familiar with (Reichelt, Conrad), same story, if the used flux is named at all.A quick search here on EEVblog showed a lot of information on the effectiveness of various types of rosin flux, water soluble flux, how much cleaning is needed, if this is difficult and such, but very little on health issues.Sorry about the long winded intro to my question, I'll cut to the chase now. What flux types would you advise if health issues would be a primary concern? How do I recognise these (chemical names or types?). Any brands (for flux, solder with flux and solder wick) you can advise that are more or less easily available in Europe?

author: Jeff_Birt
author_rank: Regular Contributor
timestamp: September 01, 2016, 06:45:34 pm
content: Rosin flux is a great all-purpose flux. A small can will last many years. You can clean it up with alcohol and a toothbrush. If you are doing surface mount parts a liquid flux is usually better. I have used both water clean and no-clean. Both produce noxious vapors, much worse than rosin. Have some ventilation. In a pinch I will exhale slightly when soldering to blow the vapors away from me. A small fan rescued from an old PC would be an inexpensive source of ventilation. I tend to want to clean up after even the no clean flux. Some liquid fluxes will clean up fine with alcohol and some require a stronger solvent. For the most part you can leave the no clean on the board but there are cases where it can cause problems. At a previous employer we had a board fail in UL testing as the no-clean flux under a few components was throwing off something (don't remember details) in an RF circuit. This only happened in a narrow humidity range and was hard to track down.

author: Ian.M
author_rank: Super Contributor
timestamp: September 01, 2016, 06:48:18 pm
content: They are all nasty, and some of the synthetics fumes are nastier than rosin( colophony) flux fumes. Its a choice between burning plastic fumes or rosin fumes, which are more commonly found as a natural component of wood smoke if you are burning non-deciduous wood.Get or make a benchtop fume filter, or if you do a lot of soldering every day, an extractor system that draws air directly from your benchtop.

author: Kuro
author_rank: Regular Contributor
timestamp: September 03, 2016, 04:16:35 pm
content: Thanks both for your informative replies. I guess this makes things easier, though not 'healthier'The rosin seems to still be the main used flux, so it's easy to get.Since I don't have room for a permanent bench, I'll make a desktop fume extractor using one of the many 12V 12cm PC fans I have lying around. Filters can be found easily. Thanks for the tip, purchased sets cost over 100 EUR, which is rather a lot for a fan and a filter.@Jeff_Birt, is it OK to use a toothbrush? Is that ESD safe enough? I do prefer to clean up the residue, even if it would not be necessary. I like things neat and tidy, perhaps too much so - I have not yet done any SMD work, but from the videos I suspect I will be trying to get all components nicely aligned and straight even if I have to resolder them 3 times