Mounting a bench-top fume extractor under the bench - Page 1
Forum section: electronics / testgear

author: aix
author_rank: Regular Contributor
timestamp: January 07, 2019, 12:30:24 am
content: I recently acquired a Metcal BVX-101 fume extractor. It is a bench-top unit, but my bench is tiny and has very little free space.I am therefore thinking of putting the extractor under the bench, either on the floor or just below the benchtop, on a shelf/ or bracket.This is my first fume extractor, and I am not sure what might be a practical set up in terms of ducts, arms, nozzles, mounting brackets and so on.Do any of you have a similar set up and wouldn't mind sharing the details, what works well for you and what doesn't etc?Thanks.

author: cdev
author_rank: Super Contributor
timestamp: January 07, 2019, 12:43:41 am
content: Edit:I remember finding a publication in the past from a British regulatory agency (HSE?) which gave a substantial amount of information on colophony (solder) allergy prevention !-------Note that if you have an available window nearby (many people in closed office buildings dont) which can be openedreplacing solder fume containing air with fresh air by sucking up the solder fume and blowing it outdoors is always going to be the best thing for health that you can do, as well as the most economical (however I'm not considering possible increased heating or cooling costs which might dictate getting a heat recovery ventilator in some situations which can recover 65% or more of the energy while providing fresh air year round and never needing filter replacement.. A double fan in a window could be made with quiet 120 mm computer fans and two screens to keep bugs out, which allowed one fan to blow in and the other out. The exhaust fan could be fitted with a short piece of flexible duct and a holder at its end so it could be put close enough to the work to be effective. The one you got looks like it might lend itself to this too if you add an additional length of duct to it. You could use the fan in the window as a booster similar to whats done with dryer fans.----end main edit---- some small edits also below-The main thing that many extractors are doingonce the filter has been in use for a few daysis likely moving the smoke farther away, so just set it up somewhere the fan can suck up the solder smoke and then push it the farthest away possible. If you need to put an additional hose on it to allow the air to be pushed even farther, by all means do it.Consider the air dynamics year round.Since I sometimes use an electric heater under my desk, blowing the smoke down there would not do because the heat would cause it to rise up where I could just breathe it again. Disregard the filter for a minute because the filter isnt the main thing thats happening there, the movement and dilution of the air is.A filter removes particulates but also cannot impede the flow of air much or a much larger motor would need to be used. A filter designed to really filter the air is likely to vastly increase the static pressure and so also the cost. Since the filter would have to be thick and bulky (a powerful fan would be needed to pull the air through a large amount of fresh, activated charcoal) and so such a system as well as its consumables are both likely to be expensive, tempting the user to not replace the filter often.Thats not so good. If the purpose of the filter is particulate filtration then a simple HEPA filter, perhaps a washable Gore Tex HEPA filter, might be preferable. If actual removal oftoxiccontaminants is desired, the lifetime of the filters would likely be days or at best, weeks not months, per filter. So the activated charcoal in most of these fans is mostly symbolic.What would work the best would be blowing the fumes out of a window to the outdoors.

author: Hydron
author_rank: Super Contributor
timestamp: January 07, 2019, 02:31:33 am
content: These are actually fairly expensive and chunky units, with a replaceable combination activated-carbon and HEPA-type filter inside. The design doesn't move the smoke very far - it is intended to actually properly filter and remove the nasties (unfortunately I do not have any hard data on how much they actually do get rid of).

author: aix
author_rank: Regular Contributor
timestamp: January 07, 2019, 02:36:30 am
content: I too haven't been successful in finding any technical data on filters used in these Metcal units.http://www.okinternational.com/metcal/english/globalnavigation/products/fume-extraction/filters/bvx-100-series

author: macboy
author_rank: Super Contributor
timestamp: January 07, 2019, 02:26:51 pm
content: Quote from: cdev on January 07, 2019, 12:43:41 amNonsense!You should see what I clean out of the tubes of my tip-mounted fume extractor. So much gets collected (and removed) from the air that the tube becomes physically blocked with colophony residue (essentially solidified flux smoke) if not cleaned regularly. That is all ahead of the filters. More again is collected in the filters, mostly in the first stage of the pre-filter. It seems to me that flux smoke is primarily particulate, and is especially "sticky" and will adhere easily to surfaces. Better stuck inside my fume extractor than in my lungs or on my walls and test equipment.If I forget to turn the extractor(s) on and simply tin the iron tip, the room is filled with a rosin smell that is far more intense that after a hour of soldering with the extractors on.I think that the biggest source of ineffectiveness for fume extraction systems is blow-by or bypass. By that I mean fumes that do not even enter the filter, due to an inappropriately positioned inlet (whether tip-mounted tube or a bench mounted funnel), or blocked tubes or filters causing poor airflow.(I'll add that a fan with a thin charcoal filter in front of it isnota fume extractor, even if it has "Hakko" or some other name brand on it. But the OP is not asking about using one of those).QuoteThe bolded textis opinion, not fact, until you cite credible sources. Activated charcoal is far more effective and long-lived than you seem to think it is.Stop spreading FUD about ineffectiveness of professional fume extractors. You are entitled to your opinion but stop presenting it as fact. Either cite sources, or preface your opinions with something like "In my opinion,", "I think that", etc.

author: coppercone2
author_rank: Super Contributor
timestamp: January 07, 2019, 02:39:04 pm
content: does anyone have data of chemical concentrations going past a carbon filter.i know they react to small hydrocarbons but how about large ones?the pore size of a carbon filter is something like 20 angstroms, but i don't know the details. i know they are known to get hot on exposure to things like organic solvent fumes. i assume given the fact they absorb alcohol its more like a range of 2-20angstroms in some kind of distribution (bell curve?)keep in mind only a portion of condensates is like, harmful, because you end up with particle sizes that you end up exhaling or that end up getting stuck in your avioli. is it useful for filtering out the particles which are sized for biological absorbation?i do have questions about filters, i.e. if you just remove the large particles, that are actually rather harmless, can you actually increase your suceptance to smaller particles (i..e they won't cause irritation and cause some kind of immune response that increases protection)? like maybe a large particle might cause coughing response that tends to clean up the lungs a bit, but just smaller ones will get directly absorbed in greater number if irritation is not present. i am wondering if partial filtration could actually make the situation worse (i typically just use dillution/air purge).

author: cdev
author_rank: Super Contributor
timestamp: January 07, 2019, 07:29:54 pm
content: First, I don't consider myself to have been talking about professional fume extractors, more like what seem to me to likely be consumer ones.elements ofprofessionalextractor.1 Big and heavy filters containing lots of activated charcoal.2 very powerful fan to draw air through 13 Date attached to filters after which must be replacedOkay, that said.. and the following is important...I don't know so much about this professional soldering station situation at all, and if one needs to know for health or especially regulatory reasons one should always be safe and ask whomever regulates workplace safety in their country (NIOSH or OSHA in the US, or perhaps ACOEM for air related things, also PubMed likely carries a lot of info if you learn how to use it.) I do know the British regulatory agency (I forget their name) has a publication specifically on colophony disease and allergy prevention. Thats where I would start.What I was getting at is that in some consumer level "fume extractors" the activated charcoal is there for marketing purposes, primarily. They likely should not be used in businesses to offer worker protection. For the same reason one wouldn't wear a cheap procedure mask (worn by doctors in operating rooms and pedestrians on the streets of highly polluted cities to keep large dust particles out of their nose and mouth and contain their spittle by their face but not impede airflow too much) when one was performing mold remediation with known toxic mold. Or similar. You would use a NIOSH certified respirator and filter approved for use with that specific situation."Activated" carbon and some other similar materials are often used in filtration because of their huge surface areas at the microscopic level. Some filter materials leverage that surface which can be absolutely huge in terms of area, to clean air of toxic substances, with different materials having an ability, when fresh, to literally grab on to and hold a subset of substances which typically includes some dangerous ones. But there is no filter which will remove all dangerous substances, and some kinds of toxic substances which are in gaseous form are very difficult to remove.Also, as you pointed out, the smaller a particle is the more likely it is to go deeply into the human lung and only the smallest particles (Lets say those of approximately one micron in size or smaller) typically make it to the portion of the lung where they can directly enter the bloodstream. Unfortunately, studies on some substances of great concern common in say, water damaged buildings, have shown that the smaller a dust particle in those environments is, is the far more likely dust filtered to remove particles above that size is to carry a high percentage by weight of those particular toxic substances. Whether that also applies in the context of soldering, (smaller size = more toxic) I have no idea. To be honest, I think the main risk of people working in electronics where rosin core solders are used is colophony disease. I dont know what the effect of overloading of a carbon filter is on its ability to filter out those particles. I think there is a good chance that at some point the filter becomes less of a sink than a delay line for such particles.Activated charcoal comes with an ability to 'bind' certain kinds of molecules to its surface, which begins when the filter is opened and continues to be used up by contaminants of all kinds, we might think of it as a clock thats running even when the fan is not running and the "fume extractor" is stored away in a closet. All sorts of molecules, most of them benign use up that capacity.So when the carbon has been exposed to the air for a fairly modest amount of time the filter no longer removes the kinds of polar molecules its designed to remove and to rejuvenate that capacity it would have to be heated up to a fairly high temperature in an oven which would send the contaminants back into the atmosphere, or replaced with a new one.

author: cdev
author_rank: Super Contributor
timestamp: January 07, 2019, 08:36:47 pm
content: Macboy,I am not arguing with your situation, and indeed its good that that junk is getting removed. Presumably your workbench is somewhere where a nearby window is unavailable.If no window which can both allow exhausting the fumes outdoors and serve as a source of fresh make up air is anywhere nearby, people do what they have to do and do it the best they can.No, I don't have any numbers bit I bet the UK HSE site would and likely thats the best source of info for people in factories especially.The two fan solution I've been describing is only an option for people with a window nearby.Here's what I built in the past when I lived in an apartment whose air was literally making me ill.I used a cheap plastic shelf that could be screwed to the wall, from IKEA as a rain shield and underneath that I put a board that had multiple quiet high powered fans in it which had been fitted with an additional bug screen. (also the apartment was on the top floor of a multistory building) This fan could blow all in or both directions (or blow out) This fan which was unfortunately destroyed and disposed of when I moved out, although I still have a smaller version of it, would have been ideal. The side that blew out could have been fitted with a duct and I had already fitted it with some vanes that made it so the two air streams were unlikely to mix on the outdoor side.Do you remember how in Terry Gilliam's dystopian film "Brazil" apartment dwellers were obsessed with air supply and ducting? Or how a very very stressed looking Fran Blanche set up an air filtration unit when she was besieged in her building by workpeople who were likely stirring up asbestos? Like that.Quote from: macboy on January 07, 2019, 02:26:51 pmDo you have a source on that!? (statement on activated carbon)I'll tell you who my sources were. Air quality professionals, a lot of them. But it wasn't in the context of solder smoke it was in the context of known to be toxic mold, a real lot of it, ("Abundant" is the word the test reports used) "Mycotoxins" are toxic substances produced by fungoi (hence the 'myco' which produce them to kill off other fungi in direct proprtion to the amount of moisture in a space that also contains mold food. So moisture, plus mold food plus air plus time = mycotoxins. If the space (typically something like the insides of walls where one side is covered with gypsum wall board, plus there is also a source of moisture, say condensation or especially leaks or wicking) is almost completely closed the RH can reach almost 100% and thats when the really toxic molds grow. Once they produce this toxic stuff its so stable it can last decades or probably even longer (it can last a very very long time, we know that much) at essentially the same toxicity level.So you're right, my knowledge was acquired about a totally different substance. As far as colophony - I was just speculating. So lets find out the facts!

author: helius
author_rank: Super Contributor
timestamp: January 07, 2019, 09:52:37 pm
content: As I have said before, the fumes from rosin flux smoke are not very toxic and air extraction would not be necessary based on toxicity. The compounds are many of the same ones present in a campfire. The reason for air extraction is to prevent rosin sensitivity syndrome (also called, as mentioned above, "colophony disease"), which curtails soldering careers. These sensitizing molecules are not volatile and settle out of the air once they cool down, so filtration is not required. The small fans that pull smoke away from the operator are quite adequate, and the low efficacy of their filters is irrelevant.That being aid, why do high-priced, HEPA filtered, air extractors exist on the market? For use with synthetic fluxes, other toxic materials like conformal coatings and glues, and for multiple operator workplaces where you cannot blow smoke away from one bench without it hitting someone else.

author: Edison
author_rank: Frequent Contributor
timestamp: January 07, 2019, 10:21:07 pm
content: I have myown production extractor mounted above the desk and exhaust gases over me. Two turbines, a pre-filter, a carbon filter, a turbine filter, output filters and hoses will hold A4 paper - bent into the suction basket.

author: sotos
author_rank: Frequent Contributor
timestamp: January 07, 2019, 11:04:08 pm
content: Quote from: Edison on January 07, 2019, 10:21:07 pmAny pictures of it ?

author: Edison
author_rank: Frequent Contributor
timestamp: January 07, 2019, 11:15:01 pm
content: Here are some pictures from the production, when I have time off nafotíme finished work.https://www.eevblog.com/forum/testgear/looking-for-fume-extractor/msg2086462/#msg2086462

author: LaurentR
author_rank: Frequent Contributor
timestamp: January 08, 2019, 09:03:13 pm
content: Quote from: aix on January 07, 2019, 12:30:24 amI have aHakko FA-430unit that sits under my desk. It works pretty well and on medium setting is bearably quiet (for a fume extractor). I use the Loc-Line based arm, clamped on the left side of my desk and bring the nozzle in when needed. I have a cramped desk and it works well for me. The Loc-Line arm is not extremely flexible, so you have to plan the space carefully, but all good otherwise. One big benefit is that you can add/remove pieces to make it just the right length (the Loc-Line pieces are std, available on Amazon). I have heard the regular arm works well too. I believe Metcal has a similar offering for their fume extractors (or you can make one yourself using off-the-shelf Loc-Line parts).My setup looks like the picture:https://www.hakkousa.com/products/replacement-parts/hakko-loc-line-kit-10189.html

author: aix
author_rank: Regular Contributor
timestamp: January 08, 2019, 10:25:05 pm
content: Quote from: LaurentR on January 08, 2019, 09:03:13 pmThis looks very promising, thanks for sharing!

author: LaurentR
author_rank: Frequent Contributor
timestamp: January 08, 2019, 10:53:21 pm
content: Quote from: aix on January 08, 2019, 10:25:05 pmLoc-Line 2.5" anti-static range:https://www.loc-line.com/products/2-5-vacuum-hose/anti-static-vacuum/

author: aix
author_rank: Regular Contributor
timestamp: January 08, 2019, 11:04:12 pm
content: Quote from: LaurentR on January 08, 2019, 10:53:21 pmThanks — I'll see if I can source these in the UK to play with. It looks like the bench clamp is a custom Hakko part? (I couldn't find it Loc Line catalogues.)

author: georges80
author_rank: Frequent Contributor
timestamp: January 09, 2019, 12:32:49 am
content: https://www.eevblog.com/forum/projects/diy-flux-fume-filter/msg636551/#msg636551from a few years back. Using loc-line mentioned in this thread. Use it a LOT and still working great.The 'outlet' sits next to a window, in summer the window (with screen) is open. In winter it 'recirculates' but is behind the curtain, so quite diffuseI replace the hand cut filter pads often enough and don't get the flux smoke in my face.cheers,george.

author: Edison
author_rank: Frequent Contributor
timestamp: January 09, 2019, 01:51:56 am
content: Functional test, temporary rubber flange will be replaced by 3D printer flange (ABS) or lathe out of duralumin

author: aix
author_rank: Regular Contributor
timestamp: January 10, 2019, 07:40:41 am
content: Quote from: georges80 on January 09, 2019, 12:32:49 amLooks nice, thanks for sharing. I've not come across Loc-Line until this thread, but looking at their catalogue I notice that they have "standard" (blue and orange) and "antistatic" (black) parts. I don't know if the latter were available when you build yours, but do you think it would matter which ones I use?Hakko uses antistatic parts. They seem harder to sources in the UK (and will presumably end up being more expensive), so I am wondering how much it matters? I have a grounded ESD mat on top of my bench.

author: georges80
author_rank: Frequent Contributor
timestamp: January 10, 2019, 04:26:09 pm
content: ^ unless you have some ESD certification requirement, I really cant imagine any issue. It's not like it it touching up against the boards you are soldering.The 'esd' black stuff was available at the time, I made a conscious decision to source the more available orange/blue. Haven't noticed any lightning bolts while in usecheers,george.