No worries, I have a few ideas for the graphite foam and sheets. Also have something else I will be working on. Just waiting for all the parts to get in my hands to try. Will take some time to experiment, nothing is just straight forward and simple.
I think the graphite felt (you can call it a foam, but it doesnāt feel like a foam matrix, more a web of fibres) on its own is better than the foil, but the two together are better than the felt alone in most locations. What I donāt know yet, because I donāt have additional layers of the felt to experiment with, is whether a felt/foil mix > 2 layers of felt. Suspect it will depend on the mix of emitted vs received RFI from the component or cable in question, with thicker felt beating felt + foil in most cases.
Re the felt, I postulate, based on both its much less dense /more porous structure, and how it sounds (fewer if any negatives so far vs the foil which had some in some cases, particularly for the thinner 0.5mm foil) that the felt has a higher ratio of RF absorption:reflection than the foil, which is in turn surely higher than copper sheeting.
I am going to experiment with the felt as internal RFI absorber in some components. One idea is to encapsulate it in a large ziplock bag and lay it directly over a circuit board, though Iād have to be comfortable with the temp of any caps etc first not melting through the plastic to expose the conductive graphite felt. Good test to see if my FLIR phone IR camera accessory still worksā¦
Probably safer to use some of this really tough āpolycroā plastic film I have lying around - used as window insulator film (3M or Duck brand on Amazon) and a
ground cloth by ultralight hikers. Shrinks/contracts rather than melts with high heat from the likes of a hair dryer on high temp up close. Very strong and hard to pierce or tear with anything short of a knifeās cutting edge or tipās sharpness. Itās a form of cross linked polyeolefin/polyethylene (XLPE) also used as
insulation for high voltage cables with a dielectric constant only fractionally higher than PTFE. Am planning to use it with a heat sealer to make really strong fully sealed bags of RS (and other stuff) in tailored shapes and sizes.
If you're considering wrapping graphite around cables, I'd strongly recommend trying
Techflex's Flexo Anti-Stat. It's a carbon-infused jacket, and brings a lot of positives on AC & DC cabling. There are a decent number of manufacturers using this -- Triode Wire Labs & CommonGround Cables off the top of my head.
Thanks again for the tip. Will look into this further, consider trying some, certainly with its woven, flexible braid itāll be much neater and easier fit on cables vs the stiff felt which can really only bend in one plane⦠into a cylinder, but nothing easily beyond that, though some selective scoring could maybe help it fit to a cable arc via a series of short straight sections.