carbon black faraday shield

[Anonymous]

Quite a while ago I came across some info on how to make a faraday shield for a coil using a paint based on carbon black. I thought the info came from this forum but when searching I couldn't find it. Can anyone out there help e.
Thanks in advance.

 

[Anonymous]

Hi Alan,
Search for graphite and you will find a couple of posts. There were a couple by Gaz specifically about making the paint. The posts were on Tuesday, 25 June 2002.
Also, there was a posting on the Geotechnology website by Dave Johnson about a particular carbon based paint that seemed to work fine. His post was on 4-5-02 and it stated:
"One conductive paint which is widely available is "GC EMI-RFI Shield" #10-4807. This is carbon-based spray paint, pretty good stuff except that on some plastics (including most ABS) the paint itself creeps and cracks. The creep-crack problem could probably be eliminated by a suitable primer; which, however, I haven't actually tried and so can't make a specific recommendation. SHAKE IT VERY THOROUGHLY, and after use turn it upside down to clear the nozzle; otherwise it'll clog."
I hope this helps.
Reg

 

[Anonymous]

I may be able to help on the paint creep and crack.
I paint motorcyles as a hobby...well used to more years ago. There is a primer for ABS plastics that prevents this. It comes in a spray can and can be found at most automotive paint stores or at realy good parts stores that sell Dupont and PPG paints.
Plastics can be a pain to paint but this primer will solve this...forgot the maker but should not be an issue.
Scott

 

[Anonymous]

Hi
I have used a spray called Graphite-33, its a spraypaint for ESD shielding of for instance a plastic box.
It worked ok for a BFO I made 10 years ago, and I also tried it on the backside of a PCB coil for a Pulse induction coil.
I found it used in a commercial VLF coil.
To make the connection to the paint, they have glued and soldered some very thin copper wires to ground and then sprayed them over.
See the link. I could not link directly to the Graphite-33 product.
Have fun.
Mark

 

[Anonymous]

I found that I had to be very careful about the connection. If a wire is used and sprayed over with conductive paint, the paint can fail to get right underneath the wire, or if the wire should move then it may crack the paint, either way it may result in a o/c or even worse an intermittant bad connection. I found that a little conductive tape with the end splayed and then sprayed over, so as to give it more edges to connect to was much better. I never really got any descent results with this spray, not when compared to other means.