zawy,
Thanks for the analytical data and regs pertaining to PCB dust, etc.
I have been curious about these topics for some time and your information is timely. I personally favor reasonable efforts to reduce PCB dust and solder fumes. For PCB dust, I use a vacuum cleaner with a drywall dust filter. For solder fumes, a small inline vent fan is used to exhaust to the outside. Your information provides assurance that my efforts are more than sufficient and relieves further concern.
I also had considerable reservations about using lead based solder paste in the home shop with small children present. Switching to no-lead solder paste alleviated those concerns.
Thanks again for the useful information.
Wayne
--- In Homebrew_PCBs@yahoogroups.com, "zawy" <zawy@...> wrote:
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> Tungsten carbide and fiberglass dust are allowed up to 5mg/m^3 in non-protected 8-hour work environments, day-after day. This is basically saying they are only twice as toxic as "non-classified dust". Each 1 mm hole in a 0.064" PCB is about 2 mg of material. If 10% floats away as fine dust in a smallish 20 m^3 room, then you need about 500 holes before a fan needs to be placed in a window. This matches well enough for our intuition. The amount of drill bit metal that escapes, by comparision, is next to nothing, but if you wear out 0.1% of a 10 gram bit in a routing application in a small 20 m^3 room, you've met OSHA and ACGIH's max for daily 8 hour exposure. The concern is usually with agressive sanding applications. There is also cobalt in these blades that is 5 times more dangerous, but 10x to 30x less of it.
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> An interesting thing is that ACGIH says hardwood dust is 5 times more dangerous. This isn't to say fiberglass isn't really unhealthy, but that you should take serious precautions to not breath hardwood dust, which goes against my intution, but I'll try to remember it.
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> This is not off topic because OSHA doesn't regulate DIY, so I think protecting ourselves is integral to our efforts. BTW, weller says lead fumes result from soldering, and some rosin turns into benzene (a carcinogen). The ACGIH recommendation for rosin is not a value but "as low as possible".
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