Are filtered solder fumes safe?

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I am soldering using lead-free solder for about 1 hour a day with a solder fume extractor that has a carbon filter that looks like the image below. The place of soldering is in a building with commercial-grade ventilation, but without the ability to open windows.

This source claims solder fumes to consist of 95% particulates and 5% gases, while this other source claims 99.5% particulates and 0.5% gases.

Considering the effectiveness of the carbon filter, the possible composition of the fumes, and location, would this setup be considered safe?

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• 1You should be aware that solder fumes, even those from leaded solder, don’t contain any lead. The fumes are entirely from the flux. That said, they’re still not great stuff to breathe–it’s just not lead as many people seem to think. – Hearth 44 mins ago
• 1If you are at a company then I would recommend it. Workers comp is way more than some silly air filter. When I’m soldering at home I use the tried and true breath out while its smokey. On the plus side blowing on the joints cools it slightly faster as well! – Parker 37 mins ago
• Well, me poor hobbyist’s life does not matter that much, so all these years I do high lead soldering without any filter: What type of solder is safest for home (hobbyist) use? – @Russell McMahon, EE SE, Asked 9 years, 5 months ago Active 1 year ago Viewed 69k times electronics.stackexchange.com/questions/19077/…. I always appreciate the guy Keynes saying: “In the Long Run We Are All Dead: ftadviser.com/european/2019/09/25/…. Cheers. – tlfong01 2 mins ago   Edit   

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In this case, “Safe” is speculative. If you want an absolute level of safety, you want a fume hood or extractor(Could be built into a window with PC fans I would note similar to a drop in air conditioning unit). Carbon filter units like that are the next best option for when a proper extractor is not an option. You would have to specifically analyse the unit in question(how often carbon sheets are changed, quality, total thickness, air flow rate per area) to know exactly what made it through the filter.

As far as different distributions of particulate and gas, there are different alloys of solder and types of flux and soldering temperatures that could account for the distribution, so both of your sources are probably right. If an extractor isn’t an option for you and you don’t fully trust your engineered unit, it’s a very simple device that would be very easy to overbuild. Add a hepa filter, increase carbon filter quality/thickness, make it easy to change and use high static pressure fans to compensate for the additional restriction. How much there was to gain from this would depend on the original engineering, but it’s an easy and cheap project.ShareEditFollowFlaganswered 1 hour agoK H2,75555 silver badges2121 bronze badgesadd a comment0

That “filter” doesn’t really do anything. The fan however disperses the fumes, which are then ideally vented out by the HVAC system without reaching harmful levels. How safe that is depends on how much air exchange you have and the volume of fumes you’re generating.

Edit: I’m surprised this is controversial, but those “charcoal filters” are worthless at removing particulates, which are the primary component in solder fumes. Take a look at the particle size that will fit through them:

Those millimeter-wide gaps are literally thousands of times too large to remove the sub-micron particulates generated by soldering. Activated carbon is more helpful at removing gases, but again, the surface area is negligible and most gases will pass through without ever encountering any surface at all because the filter is simply too thin. If you have one of these, you are depending on the HVAC system to exchange fumes for fresh air. If you can’t get access to that ventilation and are going to be generating any serious fumes, then you need a HEPA filter. Otherwise you’re just blowing the same particulates in a circle and then breathing them in.

There is a whole EEVBlog episode going over this: https://www.youtube.com/watch?v=ffaiKZMU0Lw

The specific generic filter mentioned are hard to find in the West, but there are other vendors that will sell you something similar for not very much money. They’re generally effective (will remove smoke and the order of burning flux from a room), can actually remove particulates, and the filters are interchangeable if you want to buy a name-brand or certified replacement filter rather then trust the generic parts.ShareEditFollowFlagedited 14 mins agoanswered 1 hour agouser18504795,61611 gold badge1212 silver badges1919 bronze badges

• 2Have you ever used one of these? The filters may not be perfect but they’re extremely effective. It’s definitely not just dispersing the fumes. – pericynthion 46 mins ago
• 1@pericynthion Yes, I use one regularly. And no, they provide negligible filtration. Check the EEVblog video I linked, or just look at one. They have very little surface area and almost no ability to trap particulates, unlike a HEPA filter. – user1850479 42 mins ago

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