November 27, 2012

DYI Isocyanide extraction system

After starting to spray with Uros again as can be seen in this post, I was having problems with my respiratory system and I am not sure if this is caused by the careless neglect of not using a fume extraction system or by seasonal influences in which humankind is periodically bombarded with pathogenic viruses or both. Just to be sure I am in the process of building an extraction system.

DIY extraction system under construction

When airbrushing thinner based paints isocyanide gas is released in the spray. If you google this on the web you will soon find plenty horror stories featuring this gas that isn't particularly contributing to a good health. In the contrary, it may even kill you or cause you to have very discomforting respiratory problems. So not using protection systems is just plain stupid. That's right, I was dumb as a doorknob to spray while not taking proper precautions when airbrushing urethane paints....

So I wised up and gathered the following parts to build an extraction system:
  1. A Rule bilge blower - 240 CFM, 12 volt
  2. 10 and 7 cm flexible extration hoses
  3. A piece of 14 cm square PE tube
  4. Closed cell PE foam
  5. A 90 degree angle knee connector
  6. A 40 mm PE tube
  7. Several sheets of active carbon filter material

The Rule Bilge blower is capable to move 240 cubic foot of air (and all the crap contained in it, like poisonous fumes...) per minute. You can buy it for approximately 25 Euros here in Europe. Advertisements say it operates quietly, but that is a joke, unless you're deaf already. But it excels in moving air at great pace. It was designed to extract air containing fumes from engine compartments of small boats, so it was also built to last a reasonable amount of time and is resistant to toxic fumes. It was built to run on 12 volts, but it will also run on lower voltages, making less noise and moving less air. Figure out what you need.

I mounted the blower into a short square of PE tube using two pieces of closed cell foam (so that the air does not escape in the wrong direction). The outer shape of the foam is square, a little larger than 14 cm. It needs to be fit into the tube with some force to make sure it is air tight. In the middle of the foam pieces I drilled a hole of 10 cm in diameter into which the blower is squeezed. The outer dimensions of the foam are over-sized and the circular hole diameter under-sized to make it air tight. The blower moves so much air that it will force air to escape, which it will do in any event, if necessary in the wrong direction... (i.e. back into the space where you want to get rid of the venomous gases).

The 10 cm diameter hose is clamped between the outlet side of the blower and the foam construction that I jammed into the square tube. The 7 cm diameter hose is connected to the 10 cm hose to make transition to the PE tube easier. At the end of the 7 cm hose I connected a 90 degree angle knee joint into which the 40 mm diameter PE tube fits. I drilled holes in the PE tube so that the fumes can escape to outside my house. I stuffed the end of the 7 cm hose with active carbon filter sheet material, as well as the 40 mm PE tube. This to make sure I do not poison my neighbors and reduce the noise level.

The PE tube is fitted into a windowsill - I have tilting windows on the first floor and attic. Just close the window so much that the PE tube is jammed inside the windowsill. Wrap it in foam sheets to make sure the fumes do not re-enter the space from where you want the fumes to be removed. Total costs are approximately 50 Euros. Not a lot if it will allow you to continue to breathe normally. I will post more photographs of the system as soon as I have it up and running and share more experience of its usefulness.

Happy shooting!