Carbon dust the new asbestos?

[Steve Glass]

Up until now I've only used carbon fibre sparingly, carbon rod or a few carbon tows for local reinforcement. Little or no dust generated.

I'm thinking about moulding a few carbon props, which will require some sanding to finish.  So my question is-  to protect me and my family from the harmful effects of carbon dust, what workshop practices will be necessary?

Steve

[Brett Buck]

Up until now I've only used carbon fibre sparingly, carbon rod or a few carbon tows for local reinforcement. Little or no dust generated.

I'm thinking about moulding a few carbon props, which will require some sanding to finish.  So my question is-  to protect me and my family from the harmful effects of carbon dust, what workshop practices will be necessary?

Steve

   I wouldn't recommend breathing it, but since most forms of asbestos are not dangerous and the one that are require extensive exposure over long periods, sanding a few props every now and then is very unlikely to be a serious source of risk.

      I would be much more concerned and take many more precautions against the epoxy components, those are very active chemicals and are well-known to induce acute illness even in small amounts.

      Brett

[Dennis Toth]

Steve,
I have done a number of carbon props, just use a good paint mask while sanding and either sand outside or have an exhaust window fan to take out any drifting bits.

Best,    DennisT

[Dave_Trible]

I make carbon props in batches once in a while.  I don't think the carbon/epoxy dust drifts in the air much and at best might use a simple paper dust mask.  Actually balsa dust bothers me more as I get older.  Where the carbon dust bothers me more is the 'itch' factor when cutting carbon before any epoxy is mixed or dope is applied in the case of carbon veil on an airplane.  In this respect it is about like fiberglass insulation you put in your house but not quite so bad.  I plan on a shower and fresh clothes right after I do anything with carbon simply to get rid of the itch.  The act of cutting seems to launch carbon particles not wetted (and weighted)  with something.  Here a small fan blowing the stuff away from you is a good idea and i'd think a mask more appropriate.   

Dave

[Motorman]

Sorry guys, any CF dust that gets in your lungs will never come out and it's carcinogenic. The fumes from the hardener are also carcinogenic and skin contact must be avoided. I've made hundreds of props and I'm still alive and well but I take the proper precautions. Know your industrial hygene before you mess with this high tech stuff.

MM

[Rusty]

What I would like to know is why?  Is it worth all the rigmarole you have to take and the risk to gain something you may not even be able to detect?  How much more are you going to gain from using the props everyone else uses?   

My thoughts are that we are exposed to too many chemicals just living in today's society.   

[Dave_Trible]

What I would like to know is why?  Is it worth all the rigmarole you have to take and the risk to gain something you may not even be able to detect?  How much more are you going to gain from using the props everyone else uses?   

My thoughts are that we are exposed to too many chemicals just living in today's society.

I think there are maybe a couple things that one must understand about why some of us use carbon fiber props.  It isn't really about extreme propulsion.  In fact our props are a way to leash and moderate the great horsepower our modern 'big block' competition engines develop.  Depending on our individual theory about how we like to do things most use very flat pitch props so that the airplanes aren't going 120 mph.  The engines I'm using I'm sure are at or near 2 hp wide open.  Props made from 'normal' materials may not withstand such torque and simply chuck the blades.  At the least they can flex and vibrate badly.  Carbon props are made much more stiff and can take these loads more safely.  The other thing is that we can very finely adjust the pitch of the blades using heat and measuring gages and the props will hold these very fine adjustments.  That is very hard to accomplish with commercial props. 
Sure we have to fiddle with some chemicals.   Acetone can be very toxic.  We've used it in building and painting since the beginning of time and I'm still alive and don't know anyone who has died from it.  If you buy nylon or plastic props the molding process put more solvents into the air than we do making our own.  Just about every aspect of our sport emits something not-so-great into the air.  Sure we should try to get a handle on that.  It is hard to argue the issue.   I'm told the process to mine and produce the batteries for electric is not enviro-friendly either.  So what are to give up first to improve our fate?  Our part may be self fulfilling anyway as more modelers age out and there are fewer of us around. 

Dave

Excuse me,  I'm going to the shop to fire up the torch and anneal some copper tubing to build some tanks.

[Joe Gilbert]

Steve I wet sand all my carbon props.

[Gary Dowler]

Goodness, I hope carbon dust isnt that harmful.  Ive spent most of the last 18 years machining carbon brake disks for all manner of aircraft....  Each machine is connected to a vacuum system that sucks most of the dust away, but there is still noticeable exposure.  Plant has been open for 25 years now and no one has developed any identified lung ailments or cancers yet...

Gary

[Gary Dowler]

   I wouldn't recommend breathing it, but since most forms of asbestos are not dangerous and the one that are require extensive exposure over long periods, sanding a few props every now and then is very unlikely to be a serious source of risk.

      I would be much more concerned and take many more precautions against the epoxy components, those are very active chemicals and are well-known to induce acute illness even in small amounts.

      Brett

Careful Brett, just saying something like that in California is certainly blasphemous, and most likely borderline criminal. LOL!

Gary

[Steve Glass]

Thanks for your replies.  I'm going to give it a go. Should manage to keep things safe with wet sanding and vacuum dust extraction. A pillar drill will be the only power tool used.

There's an article in the Feb83 Aeromodeller that describes how to mould propellers using moulds made from Plastic Padding, which is a lot like Bondo.

Steve