cleaning carbon fibre for use in an atty

[jonqrandom]

i've got some CF coming, to place inside kanthal coils around SS 7x7 cable wick*, and i'd like to scrub it fairly clean before i use it.

here's what i have to hand:

• some "standard thinners" (MSDS - pdf format).
• a blowtorch - not a great one, but not an oversized lighter either.
• an oven.
• hobs and pans to boil in.

i was initially thinking solvent bath, boil, bake or torch, repeat. then i started wondering about going straight from solvent bath to torch (outside with the sheet clamped to a concrete slab and any wind at my back ), and whether to go from there back to solvent bath, or boil then bath... on the one hand, i'm thinking torching the solvent straight off the sheet might leave nasty deposits, but on the other hand it might help remove the sizing. i can't find much data on the subject, so please may i borrow your brains here?

EDIT: almost forgot - in one of the studies linked below, when they get the CF to use in the study, they shove it in water and freeze it to help break it up. i'm wondering, is there any possibility that this could affect the sizing, due to the water molecules expanding and crystallising into ice? all i know is that damages biological cells but i don't have the faintest clue whether it would affect the sizing.

---

* i'm aware it's not a great deal more internally resistant than the coil over a similar area, but from practical tests i've watched it requires a great deal of pressure to establish decent levels of electrical connectivity - IOW, the dude was jamming the meter's probes in there to get down to a few ohms/cm, looked like he was nearly bending them! what would seem to be reasonable amounts of pressure yielded much higher resistance readings, around the 70s and upwards.

the reason i'm trying CF over mesh (though i have some 400 coming too lol) is due to concerns expressed eloquently in other threads about the potential for carcinogenic variants of chrome to develop on the surface of SS mesh during the oxidation process. i'm aware CF also poses a potential dust issue, but it seems to be less of an issue than silica, if the studies mentioned in this post are on the ball.

if we're going to, please could we chat about these other points in another thread? i'm sure this one's going to get complicated enough just regarding my actual question!

 

[Froth]

Do not take this warning lightly, Carbon fiber is something you need to be VERY careful with if you plan to do anything remotely close to inhaling near it. The body can not break down carbon fiber shards, they will embed themselves in your lungs forever. When I was a machinist we had to wear respirators and take all kinds of precautions when carbon was being machined, not only that but carbon shards in the air can short out electronics, drills, electric motors, televisions, if the concentration of fibers is enough in the air near an electrical device it will fry it.

BE EXTREMELY CAREFUL!!!!! I would highly advise against this personally.

 

[jonqrandom]

i appreciate your concern for my safety, however the following studies differ considerably from your contention:

http://joh.sanei.or.jp/pdf/E43/E43_2_03.pdf
http://arch.neicon.ru/xmlui/bitstre...I.38-inhaled_particles_VII-769.pdf?sequence=1
http://www.dtic.mil/dtic/tr/fulltext/u2/a228196.pdf

if you're aware of studies that show otherwise, please do link to them.

these studies all show that CF particles won't embed in your lungs forever, in fact negative effects appear to have cleared within 10 days of exposure. at least two of the studies specifically state that it appeared that macrophages (white cells) in the lungs had broken down the CF dust. both yourself (and the rats) were exposed to the potential (or equivalent) of multiple grams of dust via inhalation. i won't even be using many grams of the fabric itself, and it will be fairly well seated.

while i don't doubt that there are severe negative effects associated with constantly inhaling grams of the stuff, it appears your health and safety department were covering their backsides. i don't blame them tbh, there's always that one guy on the shop floor that'll juggle chainsaws if you let him.

i will, however, cut and install the material outside. i'll wear a dustmask too, but given the particle size it seems as though that'll be like trying to catch flour in a fishing net.

 

[Froth]

The place I worked was under a government contract, so it is entirely possible they were attempting to use scare tactics to get us all to wear our safety gear with carbon. I'll give you that for sure.

They're your lungs, if you want to trust a study from 1990 that's fine. I don't like playing with fire, personally. My issues with the studies you posted is they don't really offer any long-term view of the effects over a decade or two to see what happens later in life after exposure.

SPI Supplies - MSDS Safety - Carbon Fiber and Carbon Thread

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.

I do realize your exposure level and window is extremely small during working with the fiber, that's a good thing.

I'm not saying don't do what you're doing, obviously you already made your mind up on what you want to do...but PLEASE be very careful, I'd hate to see something terrible happen to you. Keep in mind you're using the material outside of the normal parameters it is used in as well, there isn't exactly a study for the effects of vaping a liquid through carbon fiber wicking with a heating coil around it. My main concern is what is going to happen during a dry hit, and what will be produced when that happens.

 

[jonqrandom]

hmmm, i think we were "doing science" back in the bad old 90's

speaking of bad science (on my part), it should have occurred to me sooner; you'd have been working with CF that was sized and possibly in composites, right? in which case the aerosolised dust would very likely have been pretty toxic due to all the other chemicals involved.

welp, i haven't exactly made up my mind, i'd still be very interested to see studies that show that CF dust will not degrade or otherwise leave the lungs naturally.
i can see the dry hit thing being an issue, but i pretty much assume dry hits are always an issue and keep my clearo filled accordingly - i usually refill before i get down to a quarter tank as far as dry hits go, i'm more keen to avoid them in order to avoid oxidising the stainless steel wick, which could potentially produce the toxic hexavalent chromium, which could again potentially get vapourised.

as for the "possible inhalation hazard" - that's pretty much a given, as tiny particles of even bio-compatible materials will pose an inhalation hazard in sufficient quantities - i.e. suffocation. so that applies for many things we use for wicking materials, including the very common silica (fibreglass - ugh), cottons and rayon, flexible and possibly even stiff ceramic. and, of course, stainless steel wicks could possibly produce toxic vapours if they oxidise at high heat. damned if you do, damned if you don't...

again, i would be very interested to see research that shows cellular toxicity of CF dust, as so far i have only come across research which shows the converse.

from what i've been able to glean so far, the largest potential for harm from CF fabric comes from the sizing it's coated in (epoxies, polyvinyl alcohols, other gunk), hence my desire to get as much as possible out of the fabric. ironically, i may have to use dichloromethane baths (double ugh and oh, look, more cost and disposal procedures) to try to ensure my (relative) safety.

 

[shortdraw]

Carbon fiber is some nasty stuff. Best of luck to you.

 

[Jetsetter]

ive had similar idea regarding using CF...let me know how it is...

you can heat that stuff with a torch and it wont burn, but im not sure how great it will actually wick though. When i applied resin to my CF parts sometimes id have dry spots.

 

[martinc]

CF need to cure under negative pressure (vaccum bag,autoclave,etc)

I wouldn't use that stuff in an atty...hell,I turn and walk whe I see an atty with a CF cap