Sanding a PCB - dangerous?

Thread Starter

bumclouds

Joined May 18, 2008
81
Hey guys,

I was sanding the edges of a PCB i made today. dust went everywhere and it smelt really nasty.

I got it on my clothes and my skin and I breathed a lot of it in.

How bad is it for you?

Andrew
 

Wendy

Joined Mar 24, 2008
22,243
Extremely, depending on material. Fiberglass is almost as bad as asbestos to inhale. If in doubt, wear a mask.
 

SgtWookie

Joined Jul 17, 2007
22,221
It's really not good for you at all.

Always wear some kind of protective mask when you're using a high-speed sander. If you don't have a proper mask, you can use an old undershirt that's been dampened with water.
 

jpanhalt

Joined Jan 18, 2008
11,088
I agree that dust from sanding FRP is not good for you. There are data showing it is not as bad as asbestos. It is not a definite carcinogen and has not been shown to cause mesothelioma. Acceptable levels for the dust in air are approximately 10X (voluntary) to 30X (regulatory) the acceptable levels for asbestos.

NIOSH
Asbestos: REL-TWA, 0.1 fibers/cc (fibers >5 µm long), as an occupational carcinogen (NIOSH 1992)
Fibrous glass: REL-TWA, 3 fibers/cc, for fibrous glass fibers with diameters ≤3.5 µm and length ≥10 µm and REL-TWA of 5 mg/m3 for total fibrous glass particulates (NIOSH 1977). NIOSH (1992) notes the recommendations extend to fibrous glass (including glass fibers and glass filaments) and mineral wool (including mineral rock wool and slag wool).
OSHA
Asbestos: PEL-TWA, 0.1 fibers/cc for fibers >5 µm long and length:width ratio ≥3:1 (OSHA 2001)
Man-made vitreous fibers: No specific PEL for glass wool, continuous filament glass, rock wool, slag wool, or refractory ceramic fibers is set. These materials are regulated under the PELs-TWAs of 15 mg/m3 for total particulate dusts and 5 mg/m3 for respirable particulates (ACGIH 1997).
Fiberglass and mineral wool: The North American Insulation Manufacturers Association, the National Insulation Association, the Insulation Contractors Association of America, and OSHA established a voluntary Health and Safety Partnership Program for fiberglass and mineral wool in May 1999 (Jeffress 1999; Mentzer 1999; OSHA 1999). The program established a voluntary PEL-TWA of 1 fiber/cc for glass wool, rock wool, and slag wool. It also called for the wearing of NIOSH-certified dust respirators when the PEL is exceeded and during specific tasks.
So, don't breath it, do wear a mask, but don't panic because of your recent exposure.

John
 

Wendy

Joined Mar 24, 2008
22,243
My Mom died a slow lingering death because of COPD, mainly because of maching fiber glass. The exposure was long term, and OSHA was firmly asleep at the wheel (assuming there were standards for such them, in late 70's early 80's). Most of the people in that shop died from something similar, or various cancers, so don't downplay it.

Emphasis on long term heavy exposure.
 

jpanhalt

Joined Jan 18, 2008
11,088
Okay, so I'm not going to die in 40 years due to this exposure? :)

From now on I will wear a mask.
I assume you are less than 60. :D

One thing to consider to reduce risk is to change the process. I suspect from your description that you sanded quite a bit of the board to get your final shape.

You might want to consider ways to get closer to the final shape without sanding. Some people use small bench shears. With a shear, you can pretty much cut to the final dimension.

I have been using a narrow kerf carbide blade in a small table saw. I cut about half way through from both sides, then simply snap the scrap off. I am able to cut very close to the final line that way, so any sanding for clean-up is minimal.

Others report using a wet cutting diamond saw, like a tile saw.

You can search for other ways on this forum. Cutting PCBs has been discussed several times. One thing I have found helpful is to include an etched space to outline the area I need to cut. That way, it is easy to see where the saw is cutting.

John
 

radiohead

Joined May 28, 2009
508
Also remember to wash your hands after handling electronics, lead-based solder and rosin flux. Those things aren't good for you either, particularly breathing the smoke while soldering. Dremel tools work good for rough cutting CCAs, then you can file or sand (while masked, of course).
 
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