Ventilation ideas

Discussion in 'General Electronics Chat' started by spinnaker, Oct 30, 2010.

  1. spinnaker

    Thread Starter AAC Fanatic!

    Oct 29, 2009
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    I would like to setup a ventilation fan in my basement for when I etch PCBs.

    Living in a townhouse I don't have a ton of options.

    1. If I can find a y adapter for my dryer vent I could vent through there.

    2. My old furnace has been replaced with a high efficiency furnace so I now have an extra port on that vent but my water heater is still connected to that vent. I imagine the amount of acid in the air being exhausted is extremely small but could it cause a problem with corrosion or possible fire venting this way?


    3. I could vent out the window on the extreme other end of the basement. Working there could be a problem as there is no workbench and there is little light. And it would be a long run for the duct work.


    Any other ideas other than working outside? It can be cold here in the winter. :)
     
  2. Kermit2

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    Feb 5, 2010
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    You could set up a hood and use a strong fan to pull air through a shallow pan of water treated with Bicarb of soda to catch any airborne acid. A small fish tank would work or even a gallon jug.

    This sounds like a job for: (drumroll) DUCT tape :)

    A cheap roll of newsprint paper, or just an old newpaper is always good for laying down a spill cover and protecting furniture and carpet.
     
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  3. spinnaker

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    How much bicarb would you need? Seems an expensive way to go. I imagine it would need to be changed every time I used it.

    Another thought I had would be to run it into one of those special l buckets used for dryers when you don't have a vent. Would that remove the fumes?
     
  4. Kermit2

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    Expensive? A box cost just cents, not dollars. Remember you are dealing with vapors not a whole bucket of etching chemicals. The amount of liquid needed to capture vapors will be small. A few tablespoons of soda per liter of water should suffice. You should not need more than 3 or 4 liters water. Keep it shallow, too deep and differential air pressure will not pull any air through the system.
     
  5. spinnaker

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    Duh Bicarbonate of Soda (Baking powder). :) Had a brain freeze for some reason I was thinking soda water. :) I am assuming I would need to submerse the end of the duct work coming from the fan?
     
  6. Kermit2

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    I was thinking you would send the duct work from the hood to the water dish and place the fan and maybe a taped up cardboard box over the dish to pull the air through that way. If the fan is small enough it could possibly be taped to the top of the dish to reduce volume in the low pressure part of the system. (fewer leaks that way). It will work, but unless you build custom containers and use special sealing connectors, it will look like a bodged hack built by a stooge. :)
     
  7. marshallf3

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    Jul 26, 2010
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    It wouldn't have to go through a solution, just some sort of filter bag.

    I'd get some activated charcoal or the kind they use to plant orchids in, add a box of baking soda and shake well. Then simply rig up a container such that the exhaust air flowed through there. Ideally you'd want it as close to the intake end as possible, before the actual fan if possible.

    In all honesty, unless you're gdoing a ton of etching I don't see it as a problem.
     
  8. Kermit2

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    Anything with enough porosity and surface area to capture the vapors and suspended particles will work.

    But as previously pointed out. One off's and small numbers of boards on occasions will not produce any significant amount of air pollution in your residence. Etching solutions have a much smaller amount of volatile chemical components, unlike such things as alcohols and other chlorinated/ fluoridated, cleaning solvents used on boards after they are etched. If you use such chemicals frequently then this hood and filter would be a plus.
     
  9. spinnaker

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    Sounds like an excellent idea. I had planned on using a range hood anyway. I think you might be able to get charcoal filters for them. Or just build as you described.

    Nah I am not doing a ton of etching. Just everything I read says to use good ventilation and I really do not have that in my basement. Plus I will be working with Liquid Tin which is supposed to required good ventilation.

    How nasty is all of this stuff really? I can't afford to lose any more brain cells than I already have. :)
     
  10. Kermit2

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    The solution to tin the copper is quite toxic I remember hearing. Not really a vapor producer, but mechanical agitation could put some suspended particles in the air.
     
  11. maxpower097

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    Feb 20, 2009
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    '

    Easy just hook up a squirl cage fan to an exaust hose, then tie it into a hood. Total project cost will be around $200 for something good that will vent all gases and fumes. Don't skimp on the fan though. A $100 squirl cage is not near as good as a $180 squirl cage.
     
  12. jpanhalt

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    Jan 18, 2008
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    There are lots of potential solutions to the "problem," but first can you tell us a little more about the problem? What are you using as your etchant? Are you using any agitation -- rocking, stirring, or air bubbles? Any heating?

    If you are using a method that releases acidic fomites, the cure may be different than if you are using a method that releases HCl gas. I would not recommend exhausting any acidic material through the dryer vent or heater flue, particularly if you are a renter.

    John
     
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