Solder Fume Extractor

[tiofilo75]

I have been doing a lot of soldering lately and I think its time I invest into a fume extractor. I normally just turn on a window fan but I think I am just pushing the smoke around. Is it best to build one or just to buy one that is made? I am looking at the Aoyue 486 Benchtop Solder extractor, does anyone have any experience with this model? Thanks.

Also on a side note is there really a risk for hobbyist who use lead solder? I solder maybe once a week so maybe I am just being paranoid  .

[mariush]

The temperature of the melted solder is not high enough to turn the lead into particles or vapors that would get into your lungs.  Lead won't get into your lungs (or if it does, it's in ridiculously low amount, you'd get more from the air around you)

What is bad for you is the flux inside the solder wire which melts before the solder and attacks the surface before the solder hits the surface and binds the two metals. The flux is acid in its liquid state and has some chemicals that, when turned to smoke, hurt your lungs. Long term, they can affect you.

Often, unleaded solder actually has more corrosive fluxes, because due to the higher temperatures required to melt such solders the flux has less time to attack the surfaces before its vaporized by the solder iron so its more potent, more acidic, it has more chemicals which are bad for you.  So I suggest sticking to solders with lead in them, they're usually safer.

So yeah, you should use something to push the smoke away from you, but not for the reasons you think... not for the lead. An open window and a regular fan blowing away the smoke towards the window are often enough for a hobbyist... fume extractors are more complex in the sense that they actually have a charcoal filter or some other kind of filter which traps the chemicals in it and cleans the airs.

[con-f-use]

You can make a quick calculation. Usually it says on the solder how much of it is flux in percent. Then you multiply that by the typical mass of solder you use per session and get the mass of flux per session. That mass distributes all over your soldering room (if you're using a fan). If you know the volume of your room, you can calculate the mass of the air in your room. Then you know how much of the air will be flux vapour, by dividing the two numbers.
You inhale about 5 grams of air per minute. So that gives you an absolute upper limit of flux intake per minute. It's an upper limit because at the beginning there will be close to no flux in the air and on top of that, much gets lost because of the open window. Now you can compare with the save amount of your particular flux or the LD50. Usually it's far far, far away from the first and even further from the second.

Bottom line: A good fan close to the solder and an open window should be enough even if you solder a fair bit. Your flux intake is usually dominated by what gets on your hands and even that is not too much. But wash your hand and don't eat/store food or drink in your work are. Fume extractors are used where multiple persons solder a lot for a long time each day in an otherwise unventilated room. It is also hard to gauge the effects of inhaling solder alone in scientific studies as typically people who solder are also exposed to heavy metals, etchant, developer and many other chemicals just by touching components. Its quite difficult to disentangle.

The temperature of the melted solder is not high enough to turn the lead into particles or vapors that would get into your lungs.

And even if it was, the air would cool the lead vapour very fast. Since lead is quiet heavy it would sink to the ground and never get into your lungs.

[tiofilo75]

Thanks for all the info. I never really knew that it was the flux that got you. I know of a couple of buddies at school who use lead less solder with the idea that it is safer. I would have to let them know what i learned. I guess I should not worry too much then just as long as I got good air circulating.

[con-f-use]

Arguably led-free solder IS safer as it releases less heavy metal into the environment. Lead is poisonous inside your body, can accumulate there over a long time and causes problems especially to small children and pregnant women. On a global scale to ban lead in solder for industrial production makes sense. But hand soldering is only a small part and negligible compared to things like lead salts in fertilizers and industrial large scale electronics. Unfortunately you can't mix leaded and led-free solders, so we're all stuck with lead free and the small hobbyist gets more agressive flux. So  for the general public,  for us.

[quarros]

Unfortunately you can't mix leaded and led-free solders,

Please can you elaborate on that? Sometimes I use leaded solder to desolder components or to repair cold broken joints that made with lead free solder. So I don't get what you mean.   

[con-f-use]

Please can you elaborate on that? Sometimes I use leaded solder to desolder components or to repair cold broken joints that made with lead free solder. So I don't get what you mean.   

Okay, that was the short version. Under a few circumstances you can, under most you shouldn't. Long answer:

Working with RoHS solder

If you are used to working with a very small tip on your soldering iron (such as a Weller NT1 tip) you should switch to working with a larger tip such as an equivalent to the Weller NT4 or NTAX. Smaller tips simply don’t have the thermal mass needed to work properly with RoHS solders. Don’t turn up the iron temperature too far (I use 660 to 680F/349 to 360C) since this will cause the flux to burn and make adequate heat transfer even more problematic. Speaking of flux, a more aggressive flux will be needed, and lots of it, when doing hand soldering of RoHS materials. Something like Kester #2331-ZX works well. Having an iron tip cleaner handy will be helpful as well as keeping lead free tips clean is a lot more of a chore than with leaded solders.

Note that it is unwise to mix leaded and lead-free solders, not just from a legal or environmental standpoint. As little as 0.5% of lead contamination of a lead free joint will greatly weaken the joint and lead to premature failure. Metalurgically it’s OK to use leaded solder to affix lead free components since enough lead will be present in the alloy to prevent attachment problems, but do NOT use RoHS solder to affix components with tin/lead plating on their leads as this will result in weakened solder joints.

RoHS solder joints look different. The material doesn’t wet the joints as readily as tin/lead solder, and when cooled has a dull “frosty” appearance. This is what makes using plenty of flux so important as it’s much more difficult to distinguish a “cold” solder joint when using RoHS solders. Also the transition zone of RoHS alloys is much narrower than tin/lead. One moment it’s solid, the next it runs like water. There’s no in-between semi-molten state like there is with tin/lead solders. If you’ve done any soldering on copper pipe used for potable water supply in the last 15 years using tin/antimony solder you know what I mean.

More (or less qualified answers) on the matter: https://www.eevblog.com/forum/beginners/mixing-lead-solder-with-lead-free-solder/
The safe choice is not to.

[quarros]

More (or less qualified answers) on the matter: https://www.eevblog.com/forum/beginners/mixing-lead-solder-with-lead-free-solder/
The safe choice is not to.

Okay Thanks. I thought I missed something but thankfully not. You can mix them just don't expect long lasting high quality joint... But to point out the joint was already cracked on its own so you probably making one that is actually longer lasting than the original 

[nanofrog]

Been thinking about converting an old room air purifier unit (HEPA + active charcoal) I've got stored in the shed into a fume extractor (opening a window isn't much of an option).

Figure I need to make some sort of enclosure to direct the air properly, and I've seen some Loc-Line (2.5" inner diameter) that would make a great adjustable pipe for the intake (vacuum kit sells for ~$50USD).

Any thoughts?

[M. András]

ive ordered an electromagnetic air pump for aquariums and small ponds. the thing has 35watt input power and can supply 65liter/min air. now i plan to use its intake for fume extraction if it can push that amount of air trough those 4mm id tubes im sure it can pull trough it. plan is to use some large diameter pipe or some kind of shaped box. prefilter+activated carbon sheet+activated carbon pellets and a fine dush filter after this from this goes to the extractor attached to the iron itself and maybe some coolant hoses for extra directed suction. im not sure how much if the fumes can this filter out but to be sure i just run the outlet tubing to the outside. all of this filter just to protect the pump. the pump costs somewhere 6-70bucks and the manufacturer is resun an asian company

[Alex]

As stated earlier the amount of lead that becomes vapour at soldering temperatures is negligible. In fact, it is less than 10^-11 atm (graph attached).

There is an argument that lead-free solder is worse in terms of flux fumes as the higher temperature required will cause more components of the flux to evaporate. This, of course, needs to be evaluated on a flux by flux basis, it is however a sensible argument.

Lead is not absorbed through skin - lead from solder can only enter the body by swallowing (http://www.hse.gov.uk/pubns/indg305.pdf).

Since you are in the business of making your activity healthier, you should also evaluate the best solder to use. In general, the higher temp for lead-free solder will oxidise your tip faster. Also, it makes duller joints and is more expensive. Leaded solder does better in all domains. However, it is very aggressive to copper, so if the plating on your tip goes, expect to solder to eat through it very quickly. Arguably, the tip had been damaged beforehand.

And just for laughs, in 1999 the worldwide consumption of lead in various products was 0.49%. 80% for batteries, 4.7% for ammunitions, 4.6% for paints and so on. This is from an old reference(Advancing
Microelectronics, September/October 1999 p. 29),  but it is before RoHs and gives you an idea of the proportions.

Alex

[SLJ]

A poor man's fume extractor.



If you are soldering in a larger room, find an old computer power supply and use the fan and case.  Many are 12VDC.  Use a adjustable DC supply you most likely have on the bench already to power it and adjust the speed. If you want, a dryer hose and vent can fashioned to exhaust it outdoors or to somewhere else away from your bench and work area.

[JuKu]

To answer the original question: I have the Aoyue 486, and I'm positively surprised. The hood is efficient, the range of suction is larger than one might expect, long enough not to be a disturbance on the table. The filter is effective enough for hobby use. ((Surprisingly enough, ) I haven't developed sensitivity for the fumes, YMMV.) Excellent value for money; still, you are spending $30 or so, don't expect an industrial strength unit. 

[con-f-use]

The best type of fume extractors are ones that clip on to the iron itself. Hakko and Weller both make them but they are really expensive for some reason. Aoyue make cheap ones but I don't know if they will work with any other irons.

I have found the clip-on type somewhat tedious. They get in the way, when soldering in narrow spaces and the extra tube along the cable makes movements less smooth. But their main drawback in my opinion is that you can't turn you soldering iron around to use the other side of your tip. At least provided, you don't want to fiddle with the clip-on mount all the time. I think a large, slow rotation fan, perhaps mounted on some loc-line to move it around still is the best solution.

I consider drilling holes into the edge of my workbench at an angle facing away from me. Then mounting an air-guide  on the other side of those holes (underside of my table). A fan blows into the airguide through the holes and blows solder fumes away from me. Don't know how well this is going to work. And of course the holes would be a sink for small components and the air might blow something else away, but then again, so would a fan. Also a mosquito net or something over the holes will prevent components from falling into it. I could use an even larger fan to blow air into the airguide so it makes very little noise. What's your opinion on this idea?

[nanofrog]

The best type of fume extractors are ones that clip on to the iron itself. Hakko and Weller both make them but they are really expensive for some reason. Aoyue make cheap ones but I don't know if they will work with any other irons.

Other than the fan + charcoal filter types (~$50USD), they're all expensive from what I've seen. 

I've been looking to convert a Honeywell Envirocare HEPA room filter unit I have stored in the shed (similar model), using a loc-line vacuum hose kit and make an enclosure out of either thin plywood or sheet metal to channel the airflow.

[GreyWoolfe]

I picked up a Weller WSA-350 for $30 USD off of eBay and found filter replacements for less than $10 on the internet.  I like it a lot, it does a great job of removing the fumes.  The footprint isn't big at all and there is enough power cord that having it plugged into a surge protector on my bench, I have it on the top shelf, 26 inches or 66 centimeters for the rest of the world, above my bench and can just pull it back down to the bench with plenty of wire to spare.  FYI, the power cord runs through cable pass throughs drilled into the back of the shelves.  All in all, a nice bit of kit for the price.

Tom

[CJWarlock]

I picked up a Weller WSA-350

From  what I see this unit has a noticably sized rectangular flange. Is it effective in the terms of directing the air flow? Does it help to suck all the fume from a larger distance? I'm soldering components on large boards and I'd like to know is there something that can suck the fume from ca. 30-45 cm. I don't want to have the fume extractor too close to my work neither covering the light.

[GreyWoolfe]

I haven't tested it from that far away.  My bench is kind of shallow(until I get the new one built).  It I just tested it and it works from about 15 to 18 cm.  Not going to work for your needs.

Tom, NW0LF

[nanofrog]

I picked up a Weller WSA-350

From  what I see this unit has a noticably sized rectangular flange. Is it effective in the terms of directing the air flow? Does it help to suck all the fume from a larger distance? I'm soldering components on large boards and I'd like to know is there something that can suck the fume from ca. 30-45 cm. I don't want to have the fume extractor too close to my work neither covering the light.

You'd be looking at something that uses an intake pipe, and moves a lot of air (CFM) to do what you need. Example.

[dr.diesel]

I was 10 years old when I started soldering, both of my parents were clueless as to the dangers/chemicals in solder.  I spent many many years holding the lead based solder in my mouth as a third hand while soldering, myself clueless as to the lead content, or the flux as it drafted over my head.

27 years later I have fans and wash my hands thoroughly after each use.  I'll probably die tomorrow.   

[nanofrog]

I was 10 years old when I started soldering, ... I spent many many years [of] flux fumes drafting over my head.

You're not alone, and I have some health issues as a result. 

[dr.diesel]

You're not alone, and I have some health issues as a result. 

I'm very sorry to hear.  I'd ask but I don't want to know what I'm headed for...

[SLJ]

I took both my Weller WSA-350 and my Edsyn FXF11 Fume Extractors and measured.  I measured to the furthest point each pulled all of the solder fumes horizontally so none of the visible fumes rose straight up to where your face would be.

The Weller WSA-350 pulled all the fumes I could see from up to 11 inches (~28 cm) away.  The Edsyn FXF11 pulled all visible fumes up to 8 inches (~20 cm) away. 

I think I still prefer the Edsyn as the Weller is about twice the size of the Edsyn and twice as noisy.  Even though the Edsyn only pulled from 8 inches the stand can be angled and in some cases I think due to it's smaller size and the angle it can get closer to the work without being in the way.

[Stonent]

Please can you elaborate on that? Sometimes I use leaded solder to desolder components or to repair cold broken joints that made with lead free solder. So I don't get what you mean.   

Okay, that was the short version. Under a few circumstances you can, under most you shouldn't. Long answer:

Working with RoHS solder

If you are used to working with a very small tip on your soldering iron (such as a Weller NT1 tip) you should switch to working with a larger tip such as an equivalent to the Weller NT4 or NTAX. Smaller tips simply don’t have the thermal mass needed to work properly with RoHS solders. Don’t turn up the iron temperature too far (I use 660 to 680F/349 to 360C) since this will cause the flux to burn and make adequate heat transfer even more problematic. Speaking of flux, a more aggressive flux will be needed, and lots of it, when doing hand soldering of RoHS materials. Something like Kester #2331-ZX works well. Having an iron tip cleaner handy will be helpful as well as keeping lead free tips clean is a lot more of a chore than with leaded solders.

Note that it is unwise to mix leaded and lead-free solders, not just from a legal or environmental standpoint. As little as 0.5% of lead contamination of a lead free joint will greatly weaken the joint and lead to premature failure. Metalurgically it’s OK to use leaded solder to affix lead free components since enough lead will be present in the alloy to prevent attachment problems, but do NOT use RoHS solder to affix components with tin/lead plating on their leads as this will result in weakened solder joints.

RoHS solder joints look different. The material doesn’t wet the joints as readily as tin/lead solder, and when cooled has a dull “frosty” appearance. This is what makes using plenty of flux so important as it’s much more difficult to distinguish a “cold” solder joint when using RoHS solders. Also the transition zone of RoHS alloys is much narrower than tin/lead. One moment it’s solid, the next it runs like water. There’s no in-between semi-molten state like there is with tin/lead solders. If you’ve done any soldering on copper pipe used for potable water supply in the last 15 years using tin/antimony solder you know what I mean.

More (or less qualified answers) on the matter: https://www.eevblog.com/forum/beginners/mixing-lead-solder-with-lead-free-solder/
The safe choice is not to.

Lead-free solder is weak enough as is.