bbbair

I am in the process of upgrading the landing gear on my Extra 300 (90 size) with a Carbon Fiber gear - that was about 3" too long.

No Problems just cut it off and drill a new hole!

But... after I carefully trimmed off the legs... I recalled something that I heard about CF being similar to Asbestos and the particles created in cutting can harm your lungs... [X(] [:'(] [] ... Wikipedia confirms the similarities between CF and Asbestos. [&o]

So; before I drill out the axle holes and start fileing them to fit, I plan to get out my dust mask and set up a vaccuum cleaner to keep the space clean.

Has anyone else done any homework on the subject?
Got any experiance?
Comments? []

ecmiller

Put the dusk mask on and drill the holes.

Campy

My Feedback: (1)

Also put some masking tape over both sides of the area you plan on drilling. It will help to reduce any fraying of the carbon fibers. Be aware that the CF WILL dull your drill bits quickly.

simmo8

spin the drill on high speed and drill the hole very slowley it will give you the best finish

simmo

Harley Condra

My Feedback: (4)

bbbair,
In the aerospace industry where I had a 38 year engineering career, many health and safety laws were rigorously enforced throughout our factory and experimental operations. OSHA always reared it's ugly head, but for the health and saftey benefit of all concerned.
If you don't wear a particle mask you are risking contraction of "Silicosis", but only from long term exposure. The silicone particulates will destroy the air sacs in your lungs, rendering them useless.
Doing this type of task one or two times certainly isn't accumulative exposure, and won't kill you, but why not use the mask?
Any exposure is too much as far as I'm concerned. I would recommend a particle mask each and every time you cut or sand these materials.
As a technician, later as the supervisor of our experimental and engineering support shop, I constantly had to make sure the safety rules were observed.....That's my experience.

Use the masking tape trick,and if possible, use a fishtail drill for best results.....fiberglass and its derivatives (carbon and carbon-carbon) are very abrasive and will kill off your drill bits in a hurry . A carbide or cobalt fishtail drill will make fast work of the holes. (Fishtail drills are more correctly called "Pilot point drills"). If you do any amount of composite drilling, they are worth the price. Don't spin the drill fast, as it will create excessive heat, which rapidly dulls regular high speed steel drill bits.

See www.mcmaster.com for this type of drill bit. Online catalog page 2404


Harley Condra
BVM REP
JetCat REP

bbbair

Thanks guys!

Caution is the key.

[sm=thumbup.gif]

Bad_Daddy

btw, I am a Manufacturing Engineer working in and around graphite composite structures and assemblies every day, with my laminate experience starting 39 years ago.
There is NO silicone in carbon composites, because even minute traces of silicone will prevent the resin matrix from bonding to the carbon fibers. Therefore, Silicosis is NOT the issue.
Once completely cured, there are only inert ingredients in a graphite / carbon laminate material. Human beings are carbon-based lifeforms, so our body does NOT react to the addition of carbon, especially in powder form. That is why miners develop Black Lung Disease from inhaling coal dust in the coal mines. And that is why you should wear a dust mask, to keep from filling your lungs with carbon / graphite dust that your body will not know it needs to remove.

And use an 8-facet carbide drill. Graphite composites eat cobalt only a tiny bit slower than they eat high-speed steel.

Harley Condra

My Feedback: (4)

Bad Daddy,
I was only a lowly test engineer, in the wind tunnels, sheet metal and machined parts fab, tooling and the like, but the words I remember hearing are what I described. I must have got some bad info, but the cautions for one are the cautions for all.

Not exactly silicone, but close. Not to be confused with the element SILICON.
Am I correct?:
Sand is the most abundant resouce on earth.....Most sand is quartz....silicon Dioxide.
I should have said "Fumed Silica", which comes from silica dioxide...which is the chemical name for mineral quartz and a synonym for SILICON DIOXIDE......the starting point for all glass products including carbon fiber.
SILICON is also the starting point for SILANES, which is used to make SILICONES, and other products we use daily. It is all related by the chemical starting point.
SILICA fibers ARE USED in reinforced plastic matrices.

Caution is still the correct approach. We don't need to contract Mesothelioma or any other lung cancer from any source.


Harley Condra
BVM REP
JetCat REP

Ed Smith

bbbair,

Ignore the BS just drill the holes with whatever drills you have!

Ed S

khodges

My Feedback: (1)

What Ed said, just put on the mask and drill away. But, PUT ON THE MASK.

Doesn't matter whether it's silicone, carbon, coal dust (lots more than just carbon), cotton dust, beryllium dust, or asbestos. Long term exposure can cause pneumoconiosis, which is the collective term for all the pulmonary diseases caused by long-term inhalation of fine dust. The effects come from the irritation caused by microscopic particles (< 0.005mm) that make their way to the alveolar sacs in the lung, where oxygen exchange takes place.These small particles can't be expelled, and the tissues eventually thicken and scar, impeding oxygen exchange. Mesothelioma is a type of cancer that can occur , but is primarily a result of asbestos exposures.

As a Registered Nurse for 25 years, disease is one of my areas of expertise.

kerklein2

Only if you plan on purchasing new bits or have a bit sharpener.

Ed Smith

Please. I know enough about drilling holes. A couple of axle holes is not mass production.

Ed S