Gunsmithing Cutting a Carbon Fiber Tube

[smokshwn]

Has anyone cut a carbon fiber tube at home?

If so any suggestions as to the process that worked for you to give you an good clean square cut?

Thanks, Craig

 

[km71107]

Re: Cutting a Carbon Fiber Tube

I'm not sure about cutting it smooth & square, but make sure you avoid breathing the dust. It won't do your lungs any good.

 

[AMOK!]

Re: Cutting a Carbon Fiber Tube

smokshwn,

What is the intended function of your cut CF tube?

I've used a fine-tooth (32tpi) hackshaw to cut CF tube for engineering applications. For precision work, where you want the cut plane orthogonal (perpendicular) to the tube's major axis, you'll want to use fixturing/clamps on the tube. One method is to use a simple wooden 'mitre box style' fixture, fabricated from wood.

Rip to www.carbonfibertubeshop.com/cut%20&%20bond.html, under the subsection 'CUTTING FAQ', for a primer on the subject. The article references three methods for cutting: hacksaw, Dremel tool, and wet tile saw. Personally, I have only used a hacksaw. KISS approach. Solid results.

Do NOT use a standard compound mitre saw a la woodworking. I would suggest a non-powered approach (i.e. hacksaw).

 

[ejg]

Re: Cutting a Carbon Fiber Tube

Too much heat and the resin breaks down.
Like Amok said, fine sharp saw. Rather sand or file straight if needed.
edi

 

[poonjab]

Re: Cutting a Carbon Fiber Tube

Be very careful. Breathing carbon fiber dust can kill you. I would avoid any sawing and grinding. You could try a tube cutter you can buy at home depot for cutting copper pipe (about $15?). It screws on to the tube and rolls a knife around the tube as you increase the knife pressure. Makes perfectly straight cuts.

 

[Retoocs]

Re: Cutting a Carbon Fiber Tube

When possible, make your cuts underwater or have water running over it to pull the carbon dust away. This is the best way to minimize carbon dust. You should still wear a respirator though. Carbon fiber splinters hurt and won't work its way out of your skin so wear gloves also. You skin or lungs won't reject carbon. Once it gets in you, it's staying forever unless you manually remove it.

The cleanest cut will be to cut it long then sand it down to final dimensions.

Hacksaws and cutoff wheels are more commonly used. If you have one of the vibrating cutting tools like the Fein Multimasters or similar clones, those work really well. If you have access to a bandsaw, run the blade backwards. It won't cut as fast but it also won't delaminate the fibers as you are cutting.

 

[AMOK!]

Re: Cutting a Carbon Fiber Tube

We hear this a lot, "CF dust can kill you." We need to objectively address the hazards associated with CF and then the preventative measures required to mitigate these hazards.

Posted below is an MSDS excerpt for a typicl CF composition. I have no problem cutting CF, when applying the appropriate PPE. IMO, would recommend using a face-mask respirator (with the appropriate N, R, or P filters) AND eye protection while working with CF.

See www.cdc.gov/niosh/npg/npgd0306.html for respirator recommendations based on your application (i.e. volume of CF cutting, and, therefore CF dust you are generating). In most cases, a 3M face mask respirator (w/ appropriate filter) from Home Depot for $30 will suffice.

MSDS(excerpt) for Natural Graphite {CARBON FIBER}
~ ~ ~ ~ ~

Section 1: Identification
Date Effective...... January 8, 2009 most recent revision)

Chemical family..... Graphite/Carbon

Emergencies
Contacting CHEMTREC:

24 Hour Emergency Use Only #'s......
Worldwide phone: 1-(703)-527-3887
Worldwide FAX: 1-(703)-741-6090
Toll-free phone: 1-(800)-424-9300 USA only


Product/Trade Name....Graphite (commonly called "carbon") Fiber

Emergency Overview:

Contains no ingredients now known to be hazardous by OSHA.
The normal cutting of the fiber, either with scissors or razor blade is suspected of generating small amounts of possibly respirable fibers. We believe that such fiber cutting should be done in a ventilated hood facility.

Section 2 Composition
Name CAS # Approximate Weight %

Graphite 7782-42-5 >99.99%

No hazardous components as defined by OSHA.

313 Listed Chemicals
If none are listed here, there are no 313 chemicals present above
threshold values.

NFPA (Scale 0-4): Not known

Section 3: Hazard Identification
Potential Health Effects:

Eye: Dust may cause eye irritation

Skin Contact: Dust may cause skin irritation.

Skin Absorption: Not expected to be a major route of entry.

Ingestion: Not known

Inhalation: Small graphite fibers or dust are suspected as being possible inhalation hazards.

Chronic effects: A review of the literature does not show obvious long term hazard.


Carcinogenicty: No component known to be present in this product and is at > 0.1% is presently listed as a carcinogen by IARC or OSHA unless other wise noted.

Routes of exposure: Inhalation

Permissible exposure: 15 MCCPF OSHA TWA, 10 mg/m3 ACGIH TWA (Total Dust)

CIRCLA Hazard Ratings:
Toxicity: 1 Ingnitgability: 0 Reactivity: 0 Persistence: 3

Toxicological Information:

Graphite causes benign pneumoconiosis (graphitosis). Symptoms of
pneumoconiosis from graphite exposure are dypsnea, coughing, black sputum, bronchitis, ventricular hypertropy and impairment of pulmonary function. X-rays will show progressive nodulation of the lungs. The theshold limit value was set in conformity with the limit for free crystalline silica,
which may be present in graphite.

Incompatibilies:
Strong oxidizers,fluorine, peroxides

Route of entry: Inhalation, Skin or eye contact.
Target organs: Lungs, Cardiovascular system.

Symptoms:
Coughing, forceful expiration. Dyspnea, difficulty in breathing.
Black sputum, black colored expectorate. Bronchitis, inflamed bronchial mucous membranes, pulmonary fibrosis, fibrous tissue involving lungs. Pneumoconiosis, degenerative respiratory disease.

Section 4: First Aid Measures
Eyes: In case of contact, immediately flush eyes with copious amounts of flowing water for at least 15 minutes, retracting eye lids often. Get medical attention immediately. Contact lenses should not be worn when working with this product.

Skin: Wash skin thoroughly with mild soap and water. Flush with luke warm water for 15 minutes.

Inhalation: If large amounts of the dust are inhaled, move the exposed person to fresh air at once. If symptoms persist contact
physician.

Ingestion: Not known
~ ~ ~ ~

Reference:
* NIOSH Pocket Guide to Chemical Hazards (www.cdc.gov/niosh/npg/)

 

[bohem]

Re: Cutting a Carbon Fiber Tube

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: richard_cranium</div><div class="ubbcode-body">Be very careful. Breathing carbon fiber dust can kill you. I would avoid any sawing and grinding. You could try a tube cutter you can buy at home depot for cutting copper pipe (about $15?). It screws on to the tube and rolls a knife around the tube as you increase the knife pressure. Makes perfectly straight cuts. </div></div>

This method will not work and will destroy the tube, don't use it.

The "rolling knife" works on metals much the same way that butter cuts. CFRP is brittle fibers suspended in a thermoset resin that will crack and then delaminate.

The fine saw method will work, using a dremel tool will work very well. You're probably going to need to clean up the cut line with a fine sander after you're finished either way. Respirators are a big consideration that you should use. Keeping running water over the part is a very good way to cut the dust down and keep it from being airborne.

 

[RADcustom]

Re: Cutting a Carbon Fiber Tube

I have used a cut off wheel in a dremel tool with good results. I wrapped the cut point with masking tape and marked where I wanted the cut to be. I left it a little long to allow for cleanup. If you are careful there won't be much.

 

[Outsydlooknin75]

Re: Cutting a Carbon Fiber Tube

Use some super glue or CA to seal the cut afterwards. If not fraying can happen.

 

[Phil1]

Re: Cutting a Carbon Fiber Tube

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: smokshwn</div><div class="ubbcode-body">Has anyone cut a carbon fiber tube at home?

If so any suggestions as to the process that worked for you to give you an good clean square cut?

Thanks, Craig </div></div>

I Love this line"Workin my ass off to keep stupid people procreating." It should be a bumper sticker for Firemen and cops. A super sharp pair of scissors and razor-blade is also handy to trim fibers.

 

[colchester]

Re: Cutting a Carbon Fiber Tube

I have seen carbon arrows cut with an thin abrasive cut off wheel

 

[burkeknives]

Re: Cutting a Carbon Fiber Tube

Thin abrasive cut off disk, on a bench grinder with rest.

 

[Fred_C_Dobbs]

Re: Cutting a Carbon Fiber Tube

Modern uber-light bicycle forks have carbonfiber steerer tubes that must be cut to length. I use a tool like this one as a guide:

I use a hacksaw with a decent-quality fine toothed blade for the cutting. The guide clamps to the tube, which guarantees trueness, and the blade runs through the narrow slot that starts on the opposite end (as shown) and ends at the allen screws. You could jury-rig something similar from a block of wood with a band saw, a hole drill and a Quick-Grip.

 

[biffj]

Re: Cutting a Carbon Fiber Tube

Having worked with carbon fibre extensively for many years building aircraft and their parts I wholeheartedly agree with Amok and his post. The dust won't kill you and isn't toxic though it is an irritant and shouldn't be breathed. Extensive testing in Scandanavia in the 80's was done originally to show that CF dust would cause the same issues as asbestos but the studies showed the exact opposite. CF fibers tend to break into sizes that are easily removed from lung tissue over time or into those that are longer and easily prevented from entering. CF dust will cause some pretty bad itching and irritation so avoid contact. If you do have contact with the dust wash it off with soap and water prior to rubbing it in by scratching. Wear a respirator or dust mask and also long sleeved coverings.

Now having said all that....
The best way to cut carbon composites is with high speed abrasive cutting materials. We most frequently used aluminum oxide cutting wheels with a water spray both to keep dust down and also to cool the cutting surface. Excess heat will burn the resin binder and leave a fuzzy edge. The water coolant will prevent that and leave a nicely polished edge. Cutting tools with teeth like hacksaws tend to rip fibers and leave rough or fuzzy edges. The water for cooling should be clean pure water with no soaps or additives. Silicone which is sometimes used in soaps can migrate into the laminate causing delaminations which can lead to structural failures. If you do find yourself with fuzzy edges you can clean them up with 180grit or finer wet sanding paper and water. Wet sanding will help prevent the spread of the dust.

Depending on what you are doing with the carbon tube you may need to use extreme care or not. If you are using this part as a structural element be very careful with how you cut and shape. If its just a dress up part than chop it with a handsaw, sand it smooth and be happy. Let the punishment fit the crime so to speak....

Frank

 

[Shortdraw]

Re: Cutting a Carbon Fiber Tube

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 73 fastback</div><div class="ubbcode-body">I have seen carbon arrows cut with an thin abrasive cut off wheel </div></div>
Yes, take it to an archery shop. Most shops have an arrow cutoff saw. Most arrows nowdays are made of multistrand carbon/graphite, or carbon weave. They come from the factory as plain shafts and have to be cut, inserts epoxied in, and fletching glued on. Any good archery shop can cut it with precision, square it, and seal the ends with epoxy for about $5-$10.

 

[gme]

Re: Cutting a Carbon Fiber Tube

In another life, I built several cut off saws for fishing tackle and golf shaft manufacturers around the country, they were wet abrasive saws (used a diamond blade) similar to a tile saw except with the motor under the table, the key is to roll the tube through the cut so the burr ends up on the inside of the tube.

 

[smokshwn]

Re: Cutting a Carbon Fiber Tube

Thanks for the replies....hadn't even occurred to me to try an archery shop...might try that first if not I think I can handle the dremel job at home.

BTW I am just shortening up a rifle length free float tube for an SBR build.

Take care, Craig