Pocket Sized Fume Extractor DIY Project

By Mark de Vinck

Assembly Time: 1 hour
Skill Level: Beginner

A fume extractor uses an activated carbon filter and fan to remove the smoke and noxious fumes created from soldering. The price of an extractor averages about $100. Follow Marc as he makes one that will cost about $10. Remember to always work in a well-ventilated area.

fumeextractor figure 1

Required Tools:

Soldering Iron Solder
Third Hand
Safety Glasses
Hot Glue Gun
Small Saw (Dremel)
Tin Enclosure

Fume Extractor Kit Includes:

Parts List:

Qty. Part Description Manufacturer Part Number
1 Voltage regulator 7812T
1 12VDC fan KDE1204PFVX11.MS.A
1 Slide switch 35-202-BU
2 Two fan guards SC40-W2
1 Replacement filter (3 pack) WSA350F
1 Heat shrink FIT-221B-1/16-BK100
1 Jumper wire 9313-0-R-25
1 Tin enclosure
2 9V batteries L6F22/VINNIC
2 Battery clips A104-R

Step 1: Build the Circuit

A quick mock-up is always a good idea, I'm glad I made one. At first, I thought running the case fan from one 9 volt battery would provide adequate power. In the end I decided that 12V "sucked" better, and in this case that's a good thing. The final circuit (right) uses a simple switch, two 9V 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.

fumeextractor figure 2

Step 2: Solder the Components

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The battery connectors are not the hard plastic type but the flexible vinyl version. 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. Use heat-shrink tubing on all connections – this is in a metal box and metal conducts electricity!

Step 3: Make Sure the Components Fit

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Although a bit snug, 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

Always wear safety glasses when drilling and cutting metal!

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I used a template and a marker 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.

Step 5: Paint and Decorate

I decided to paint the tin and 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!

I marked the opening for the switch and cut all openings with a Dremel tool and cutoff wheel.

Next I marked and drilled two mounting holes: one for the switch screws and one for the regulator.

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Step 6: Attach the Regulator and Switch

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Screw in the regulator 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. You can screw in the switch, we found this step unnecessary but you may follow it for extra precaution.

Step 7: Add Filter and Screens

The guard-filter-fan-guard sandwich. You can buy replacement filters for the commercial extractors at a reasonable price and cut them to size.

Next, hot glue or epoxy the corners of the screens to the tin and sandwich the filter and fan in between. Compression will ultimately hold it all together.

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fumeextractor figure 12

Step 8: Test the Extractor

Now that you're done, it's time to put it to the test. 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, 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 area at all times.