Make: Projects

Mini Fume Extractor

Candy tin device helps keep your air clean and your lungs healthy.

Mini Fume Extractor

A fume extractor uses an activated carbon filter and fan to remove the smoke, and noxious fumes, created from soldering. The average price of a small hobby version is about $100, but this one made from the ubiquitous candy tin will run you more like $10. This mini fume extractor won’t be as effective as a larger one, but it’s definitely better than nothing, and extremely portable. Remember, always work in a well-ventilated area.


Step #1: Build the circuit.

Mini Fume Extractor
  • I decided a quick mock-up might be a good idea, and I’m glad I did. At first, I thought that running the case fan off just one 9-volt battery would provide adequate power. In the end I decided that 12 volts “sucked” better, and in this case that’s a good thing. The final circuit (at right) uses a simple switch, two 9-volt batteries, a 40mm case fan, and a 7812 voltage regulator. The 7812 takes voltage from the 9V batteries wired in series and steps the voltage down from 18V to 12V, which is what the fan requires.
  • CAUTION: Wear safety glasses when drilling and cutting metal!

Step #2: Solder the components.

Mini Fume ExtractorMini Fume ExtractorMini Fume Extractor
  • Notice the battery connectors; they’re the flexible vinyl version, not the hard plastic type. This allows both batteries to fit in the case. The vinyl snaps are only minimally smaller, but it’s enough to make the difference.
  • This is a very simple circuit. Solder it according to the diagram, making sure to attach the component leads to the 7812 properly. Don’t forget to use heat-shrink tubing on all connections; this is in a metal box ... and metal conducts electricity!

Step #3: Make sure it all fits.

Mini Fume Extractor

It’s a snug fit, but you should be able to stuff everything into the tin, packing the batteries side by side next to the fan.

Step #4: Cut and drill the holes.

Mini Fume ExtractorMini Fume ExtractorMini Fume Extractor
  • I used a marker and a paper template for the fan openings, making them 35mm square on each side. After you cut the first fan hole, close the box and use the template to align the second hole. You can just “eyeball” the placement. There’s room for error.
  • Then I marked the opening for the switch and cut all openings with a Dremel tool and cutoff wheel.
  • Next I marked and drilled 2 mounting holes for the switch screws and one for the regulator.

Step #5: Paint and decorate.

Mini Fume ExtractorMini Fume ExtractorMini Fume Extractor

I decided to paint the tin this time, unlike my plain RuntyBoost ( I chose a nice red Krylon paint. I hot-glued a scrap piece of wood to the inside, so I could hold it while I spray-painted it. Two quick coats and I think it looks good. Spray paint can be fairly toxic and flammable, so paint outside and away from everything!

Step #6: Attach the regulator and switch.

Mini Fume ExtractorMini Fume ExtractorMini Fume Extractor

First, screw in the 7812 using some washers and a screw to space it slightly away from the side of the tin. I used a #6-32 screw and one washer to keep it from the edge, but you can use anything that fits. The screws and washer will also act as a heat sink. Finally, screw in the switch.

Step #7: Add the screens and filter.

Mini Fume Extractor
  • Take a look at the screen-filter-fan-screen sandwich. The screens are 50mm square and the filter is 40mm square. You can buy replacement filters for the commercial extractors at a reasonable price and cut them to size.
  • Next, just hot-glue or epoxy the corners of the screens to the candy tin, and sandwich the filter and fan in between. Compression will ultimately hold it all together. You’re done!

Step #8: Test your extractor.

Mini Fume Extractor

I’ve run mine continuously for hours and have had no heat buildup from the 7812, and the fan is still running strong. It works quite well, and although it’s no replacement for a large fume extractor, it will come in handy for small projects. Remember, follow all safety guidelines when soldering, and work in a well-ventilated room, even if you have a fume extractor.


This project originally appeared in MAKE Magazine Volume 19.

Related Posts on Make: Online:

How-To: Candy Tin Fume Extractor

Weekend Project: Mini Fume Extractor

Marc de Vinck

Marc de Vinck

I'm currently working full time as the Dexter F. Baker Professor of Practice in Creativity in the Masters of Engineering in Technical Entrepreneurship Program at Lehigh University. I'm also an avid product designer, kit maker, author, father, tinkerer, and member of the MAKE Technical Advisory board.


  • Marc de Vinck

    Yes, but for what voltage?

  • AnnikaSkywalker

    Could you share your list of items? I would be very grateful! I’m having a class of kids make this as one of their first “safety” projects.

  • AnnikaSkywalker

    Could you share your list of items? I’m having a class of kids make this as one of their first “safety” projects.

  • Chandra

    I’ve heard there is no such thing as a stupid question but what happens if I add a 3rd 9v battery in here? It is still within the limits of the voltage regulator (35V) but does it make any difference to the lifetime of the batteries this way? i.e. does adding another battery add to the lifetime?

    @ashwin: the Pin 1 is the power supply, Pin 2 is the device you are connected to, Pin 3 is ground, may or may not be left connected. I did not connect mine and it worked fine.

  • Lisa

    NO, I’m sorry this wouldn’t remove enough fumes if you’re a serious metalsmith. Only if you rarely solder and definitely NOT if you use a real torch! Irresponsible!

    • TheMarine

      This was never meant to be used by an all-out metal smith, but electronic hobbyist who sometimes need to get rather close to the components they are soldering. Take a torch to any epoxy-resin electronics PCB and the fumes from solder are the least of your worries. The only thing “irresponsible” is your prejudice against a project that you do not even understand, nor
      comprehend it’s intent.

      I have made two of these (with two fans and external power supply). One sits by my soldering station and I place the other within a few inches of whatever I am soldering. Plus, I have a DIY air purification system for my garage that I made from a centrifugal fan (removed from an A/C unit that my neighbors were replacing in their 2,000sqft house. Can’t remember the CFM of the fan, but that should give you some idea of it’s size.) and layered Filtrete 600 and1900 filters on each end.

      This fan is not the best option, but it is better than nothing. All I’m saying is that you should take the time to learn what a project is about and the targeted audience before you diss it!

  • Hi,
    Thank you so much for sharing your blog.Fume extractor system design is exextensively used for removal of fumes, mist, smoke, fine powder. Fume extractor manufacturers in Bangalore, India. Fume extractors which we manufacture can also be fitted with the self-balanced extractor arms of the varied lengths to provide with an extra flexibility in capturing the fumes.

  • Dave Ron Blane

    WHAT a RIDICULOUS WASTE OF TIME! Have you tried jerking off? better for ya!

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  • Nick

    Using a 7812 here isn’t a great idea – it’s a linear device so you’ll be
    losing 6V of your 18V as heat – that means you’re only running 66%
    efficiency. Which is very annoying when you’re using expensive 9V
    batteries. Instead, use a switched mode dc-dc converter; they are less then $2 – comprable to the cost of a 7812.

    Think about what you’re doing end to end before you start just bolting pieces together. You’ll have better outcomes.

    • Kevin Moody

      Nick, you are right, but your last sentence was just rude and tasteless. But really the point here is that he took what he had on hand and mostly just and repurposed it into something useful. That’s what we call “quick and dirty” it ain’t pretty but it get’s the job done. I happen to have ALL these parts minus screens in my junk bin and in maker fashion I’ll improve on it with another switch and protection diodes to change between battery and wall wart so I can maximise it’s use.

  • Jason Brambach

    Does anyone know how to speak respectfully? Come on guys. Show a little class. Instead barking at others post your own ingenious creations. Meanwhile, be polite or stay away, please.

    • Donald Merand

      I totally agree with Jason here. I really loved and was inspired by the idea of this project – a small battery-powered fume extractor which I can place exactly where I want it, since my soldering happens in random areas from time to time :)

      So I made one, and in keeping with the spirit of DIY I made it… a bit different. Engineering purity concerns aside, I figured I could get closer to the 12V of the computer fan and skip the regulator if I just used three 3.7V LiPo batteries. I happen to have an entire bin of donated cell phones, with their batteries, just waiting for a project like this. So I picked three that matched, put connectors on them so I could recharge them, charged them all up and verified that they aren’t bad, and wired them in series. I read that parallel LiPo batteries are bad because you can blow them up with overcurrent, but series is fine as long as you don’t mind manually balancing cells for recharging. This approach has the side-benefit of being rechargeable (if you’ve got a LiPo charger).

      I didn’t have time for a nice metal enclosure, and also my fan is too big for a tin, so I used… a cardboard box. Turns out that a cardboard box is nice because it’s easy to open + close reliably, for when you want to change the filter or recharge the batteries. The filter I used is just some piece of foam from another torn-apart project, but someday I’ll get some charcoal compost filters or something.

      So, I’d like to say thanks for Mark de Vinck for the inspiration, and don’t worry about folks who want to spit vitriol rather than participate.

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  • Brian Bloom

    Most PC cooling fans work fine when undervolted (in fact this is often done to have them run quieter, especially in home theater PCs or set-top boxes). A 9V battery should be fine for a 12V fan without the efficiency loss of a regulator. If you want the longer battery life, you could wire the 9V batteries in parallel.

    See fore more about undervolting fans.

  • George Carlson

    I hate to be critical as well, but the use of two 9V batteries and a devise that throws away so much power looks repulsive to the experienced engineer. The 9V battery is a very expensive (and temporary) device. For the price of two batteries you could by a 12V wall wart off eBay. It will last much longer.

  • Kevin Moody

    I like the maker quality of this!! The point here is that he took what he had on hand and just and repurposed it into something useful. That’s what we call “quick and dirty” it ain’t pretty but it get’s the job done. I happen to have ALL these parts minus screens in my junk bin and in maker fashion I’ll improve on it with another switch and protection diodes to change between battery and wall wart so I can maximise it’s use.