DIY fume extraction

[KaneTW]

My planned (hobbyist) soldering area has ventilation tubing running through it that I use for coffee roasting exhaust.

I'm thinking about installing a sufficiently strong fan, backflow prevention and an adjustable nozzle. Ventilation leads outside, and I live in a sparsely populated area.

Questions are:
* Is this viable in the first place, or are filters necessary? (i.e. are the fumes toxic enough that exhausting them outside is bad)
* If viable, how effective does the backflow prevention need to be? Is e.g. http://www.takagi.com/products/venting/parts/5-backflow-preventer sufficient or do I need positive air pressure?

[helius]

* Is this viable in the first place, or are filters necessary? (i.e. are the fumes toxic enough that exhausting them outside is bad)
* If viable, how effective does the backflow prevention need to be? Is e.g. http://www.takagi.com/products/venting/parts/5-backflow-preventer sufficient or do I need positive air pressure?

You don't say what materials you will be using, but rosin flux fumes are not toxic at all. The problem is that overexposure can sometimes lead to sensitization, which causes a kind of allergic reaction on subsequent exposure. Fume extraction is how technicians hope to prevent the sensitization.

Certain solvents used for board cleaning are actually toxic (luckily the worst are mostly phased out, like n-hexane and n-propyl bromide), and something like a fume hood would be needed if they are in regular use.

[KaneTW]

Thanks. I don't think I plan on needing it for anything but flux fumes (planning on doing a lead-free process with R0L0), so it seems my plan is sufficient---I mostly just want clean air while soldering.

[Cliff Matthews]

FWIW, quiet 12v "squirrel cage" fan/motor assemblies can be cheap at your local auto-wrecker.

[DerekG]

FWIW, quiet 12v "squirrel cage" fan/motor assemblies can be cheap at your local auto-wrecker.

Or a 12V desktop case computer fan. You can mount this into an upside down plastic bucket.

For ducting, purchase some 100mm or 150mm aluminium ducting from the hardware store. They sell it for ducting the hot air away from clothes dryers.

[KaneTW]

Yeah I already have a duct system installed, just need to connect to it with a sufficiently powerful/quiet fan.

[Eka]

Stick the fan at the far end of the duct. It will be much quieter where you are working. I use a very low noise bathroom fan mounted in the ceiling. I made a cone that I push up against it, and use dryer vent tubing for the duct from my workspace. For the fan's exhaust, it goes through a 4" PVC drain pipe to the soffit area and is exhausted through a vent there.