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lineinthewater 05-01-13 05:18 PM

Cutting carbon
 
I've seen bike shops cut carbon with no protection whatsover, allowing the dust to fall on the floor/table. I just finished cutting my first carbon steerer. I did it outside, with a protective mask. Do most shops handle carbon with such care?

kenji666 05-01-13 05:20 PM

People are made of carbon. What's the concern?

fietsbob 05-01-13 05:22 PM

8 story sweat shop collapses in Bangladesh .. it all depends on the business owner's priorities.

Airburst 05-01-13 05:28 PM


Originally Posted by kenji666 (Post 15576904)
People are made of carbon. What's the concern?

Your bones are made of calcium and phosphorus. Wanna eat a lump of calcium or snort a line of powdered phosphorus?

Less snarky answer, the problem is the form the carbon is in. In people, it's in chemical compounds, in a carbon-fibre composite structure like a bike, it's in fibres. I don't know for sure, but I have a feeling that the dust from cutting carbon composites may be similar to the fibres that come off asbestos when it disintegrates, and it's well-known how nasty those are. I don't actually know for sure, but even if it's just fine dust, breathing in large amounts of it is not a good idea.

I know my university does some work with carbon composites for motor vehicles, and they require the use of a mask when cutting it from what I'm told. I don't know if that's just arse-covering in case of some sort of lawsuit, or if it's genuinely necessary.

FBinNY 05-01-13 06:04 PM

The issue with cutting carbon is inhaled dust. This is a real concern when using power tools, but far less so when cutting stuff with a hacksaw. Saw dust is coarser and heavier that the fine dust that grinding creates. Once the dust settles to the floor it likely stays there, and isn't raised high enough to breathe (except if you're a dog) so of little concern. Normal good housekeeping manages it fine.

Also consider that standard industrial protocols are designed for workplaces where stuff is done all day, every day or at least fairly routinely. For a bike shop that cuts a fork now and then the total exposure is far less, so the risk to health is likewise lower.

caloso 05-01-13 06:07 PM


Originally Posted by FBinNY (Post 15577027)
The issue with cutting carbon is inhaled dust. This is a real concern when using power tools, but far less so when cutting stuff with a hacksaw. Saw dust is coarser and heavier that the fine dust that grinding creates. Once the dust settles to the floor it likely stays there, and isn't raised high enough to breath (except if you're a dog) so of little concern. Normal good housekeeping manages it fine.

Makes sense to me. (Cut last 2 carbon steerers with an ordinary fine hacksaw blade, a steady hand, and no mask)

cycledogg 05-02-13 09:17 AM


Originally Posted by lineinthewater (Post 15576900)
I've seen bike shops cut carbon with no protection whatsover, allowing the dust to fall on the floor/table. I just finished cutting my first carbon steerer. I did it outside, with a protective mask. Do most shops handle carbon with such care?

Measure twice, cut once. We never worry about carbon dust. But as stated, we don't cut all day, every day. If you are highly allergic to dust or fell the need for added safety, by all means wear protection.
Cheers

HillRider 05-02-13 11:10 AM

Carbon dust is not asbestos, coal dust or silica dust and is reasonably benign. Breathing it all day every day certainly isn't recommended but occasional exposure isn't harmful.

Here are a couple of MSDS references:

http://www.carboncompositesinc.com/pdf/MSDS%20CCI.pdf
http://www.tapplastics.com/uploads/p...er%20Sheet.pdf

Note these MSDS sheets cover straight carbon fiber and cloth, not the resin bound composites used in bike components. Thsee composites would be even less irritating.

JTGraphics 05-02-13 11:25 AM

Be leave me we breath much worse stuff than that everyday out side :) a small cut isn't going to make you fall over unless you are allergic to it or something.
If you did it everyday I would wear something thats for sure, and when you do cut just use some common scenes and try to avoid what you can its not hard.

Number400 05-02-13 11:46 AM

My understanding is that the tiny tube-like shape of carbon fragments is the issue. They are too large to be absorbed into the bloodstream and too sharp to be expelled out from breathing. They won't "seed" but will get covered over and enough exposure can cause problems. An occasional cut at home should not be an issue. Heck, it's dangerous to breathe too much flour dust if you work in a bakery.

Airburst 05-02-13 03:14 PM


Originally Posted by HillRider (Post 15579826)
Carbon dust is not asbestos, coal dust or silica dust and is reasonably benign.

OK, looks like my advice is a little paranoid. Good to know it's not too nasty.

davidad 05-02-13 04:00 PM

Most people use the paper dust masks and they will only keep out dog hair and cannon balls. If the dust were a carcinogen you would need a mask with HEPA filters to be of any value.

Kimmo 05-03-13 09:10 AM

When I worked at Applied Composites, my boss told me the issue is that the carbon is chemically inert, so the body has very limited means to expel inhaled dust and so on... he gave me an example of a splinter he had for months.


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