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Mini Fume Extractor
From MAKE Magazine
This project first appeared on the pages of MAKE magazine.
Candy tin device helps keep your air clean and your lungs healthy.
- Author: Marc de Vinck
- Time required: 1 hour
- Difficulty: Easy
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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.
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Edit Step 1
— Build the circuit.
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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!
Edit Step 2
— Solder the components.
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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!
Edit Step 4
— Cut and drill the holes.
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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.
Edit Step 5
— Paint and decorate.
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I decided to paint the tin this time, unlike my plain RuntyBoost (makezine.com/go/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!
Edit Step 6
— Attach the regulator and switch.
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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.
Edit Step 7
— Add the screens and filter.
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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!
Edit Step 8
— Test your extractor.
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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 guide has been completed 32 times.
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Guide
You can't find tins that are fat like this. If you don't have a dremel you can cut out the square using a hammer and a knife. I used a 7.2 v 1500 ma rechargeable battery and a 24 v computer fan. Worked great! Overall it is a great project for soldering minors.
Yes, but for what voltage?
The units I built used activated charcoal (carbon) filters designed for aquarium filters, they can be bought cheap at second hand store (use only the new ones!). The stronger the fan (look for high CFM/high current consumption) the more efficient the system is (but the portability diminishes). Power packs ("wall warts") are better for power, after all, if you're soldering, you most likely have access to a power source.
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you might want to add an ac adapter jack or some how build it so you can run it on rechargeble batteries and then charge it. i would do that and put a light in so you know its chargeing
If you can't get a tin, a small projects box (ABS Plastic or similar) will do, saves painting it too. Be careful with cutting it however, can be a little messy and some Dremel like tools don't cut it so well (At least from my experience anyway, may be a case of technique rather than tools).