carbon fiber used as EM shield?

neutron7 · 16th December 2006, 02:46 PM

Carbon fiber conducts electricity rather well I was wondering how it would work as electromagnetic shield, or is it something else about metal that does that?

I was thinking of bulding a carbon fiber amplifier housing. since i have some of the cloth spare from another project.

I_Forgot · 16th December 2006, 05:45 PM

Carbon fiber will work as a electrostatic shield but just like aluminum, it won't help with low frequency magnetic fields.

I_F

neutron7 · 17th December 2006, 09:53 PM

how about embedding some of this http://www.twpinc.com/twp/jsp/product.jsp?type=3
copper RFI mesh in the carbon between the layers.

I_Forgot · 17th December 2006, 10:31 PM

I don't think you need to. The copper mesh blocks RFI because it is a conductor that will ultimately be tied to the ground of your circuit. The carbon fiber will do the same thing, just as an aluminum enclosure would do the same thing. The copper mesh is normally used where you need to have shielding and air flow.

Copper is a bit better conductor than carbon fiber, so it may be slightly more effective, but how effective do you need it to be? It is one thing if you're trying for agency approval to mass produce a product and another if you're building a single device for your own use.

None of these shields (aluminum, CF, or copper mesh) will protect your circuit from low frequency fields such as those found in the vicinity of power transformers.

I_F

neutron7 · 18th December 2006, 02:23 AM

great then you saved me $75

I_Forgot · 18th December 2006, 02:52 AM

I have been considering using it for the stators of an electrostatic speaker. It should make for a stiff, light driver.

I've been trying to figure out how to pull every other cord out of plain weave cloth so it will be perforated. I need to attach the whole cloth to a frame, then cut every other cord and pull it out. It would probably be cheaper to buy the cord and just wind it over a frame with a bunch of nails or slots spaced evenly around the perimeter.

Aircraft Spruce has 1 lb rolls of 6k tow for about $50. I figure a pound of the stuff would be good for a decent sized pair of speakers.

I'd fill the frame with the stuff, then slather on the epoxy, then vacuum bag the whole thing. After the epoxy has fully hardened cut it away from the frame. The frame will have to be a throw-away part so figuring out how to make it quickly, easily, and cheaply would be the main challenge.

I_F

Nordic · 19th December 2007, 04:59 PM

Well i'd say you can use those powedery molds similar to old fashioned sand... you make an impression in it, say, useing a wooden block, then fill it with whatever you are casting with... obviosly you need to put your wires and stuff in the prepared hole before filling...

16th December 2006, 02:46 PM	#1
neutron7 diyAudio Member Join Date: Dec 2003 Location: Toronto Canada	carbon fiber used as EM shield? Carbon fiber conducts electricity rather well I was wondering how it would work as electromagnetic shield, or is it something else about metal that does that? I was thinking of bulding a carbon fiber amplifier housing. since i have some of the cloth spare from another project.

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16th December 2006, 05:45 PM	#2
I_Forgot diyAudio Member Join Date: Jan 2005 Location: Phoenix, Az.	Carbon fiber will work as a electrostatic shield but just like aluminum, it won't help with low frequency magnetic fields. I_F

17th December 2006, 09:53 PM	#3
neutron7 diyAudio Member Join Date: Dec 2003 Location: Toronto Canada	how about embedding some of this http://www.twpinc.com/twp/jsp/product.jsp?type=3 copper RFI mesh in the carbon between the layers.

17th December 2006, 10:31 PM	#4
I_Forgot diyAudio Member Join Date: Jan 2005 Location: Phoenix, Az.	I don't think you need to. The copper mesh blocks RFI because it is a conductor that will ultimately be tied to the ground of your circuit. The carbon fiber will do the same thing, just as an aluminum enclosure would do the same thing. The copper mesh is normally used where you need to have shielding and air flow. Copper is a bit better conductor than carbon fiber, so it may be slightly more effective, but how effective do you need it to be? It is one thing if you're trying for agency approval to mass produce a product and another if you're building a single device for your own use. None of these shields (aluminum, CF, or copper mesh) will protect your circuit from low frequency fields such as those found in the vicinity of power transformers. I_F

18th December 2006, 02:23 AM	#5
neutron7 diyAudio Member Join Date: Dec 2003 Location: Toronto Canada	great then you saved me $75

18th December 2006, 02:52 AM	#6
I_Forgot diyAudio Member Join Date: Jan 2005 Location: Phoenix, Az.	I have been considering using it for the stators of an electrostatic speaker. It should make for a stiff, light driver. I've been trying to figure out how to pull every other cord out of plain weave cloth so it will be perforated. I need to attach the whole cloth to a frame, then cut every other cord and pull it out. It would probably be cheaper to buy the cord and just wind it over a frame with a bunch of nails or slots spaced evenly around the perimeter. Aircraft Spruce has 1 lb rolls of 6k tow for about $50. I figure a pound of the stuff would be good for a decent sized pair of speakers. I'd fill the frame with the stuff, then slather on the epoxy, then vacuum bag the whole thing. After the epoxy has fully hardened cut it away from the frame. The frame will have to be a throw-away part so figuring out how to make it quickly, easily, and cheaply would be the main challenge. I_F

19th December 2007, 04:59 PM	#7
Nordic diyAudio Member Join Date: Sep 2005	Well i'd say you can use those powedery molds similar to old fashioned sand... you make an impression in it, say, useing a wooden block, then fill it with whatever you are casting with... obviosly you need to put your wires and stuff in the prepared hole before filling...