"..Many people have inquired about where to buy Teledeltos paper. The original source in England will still sell you a big roll for $95, including shipping;
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will get you to the right address for Sensitised Coatings, or call +44 1553764836. Plus, a new source for resistive paper is online: www2.pasco.com/products/scripts/products.taf?PN=PK-9023. The KIT PK9023 costs $114, but PK9025 paper with centimeter grid runs $34 for 100 23- by 30-cm sheets. Buy your own pen with conductive silver ink. This is about 32 kO/square. "
This is intriguing; but is the paper only conductive on one side? The reason I ask is that for my application, electrical current will be conducted through the sheet from face to face, not along its length/width.
If it is resistive throughout it might work well indeed. Is it?
Don, Your previous comment (Jan 3, 8:32 am) implies you are interested in current flow that is due to electrical boundary conditions on opposite sides of the sheet. Is that correct?
Your original post said.."Here are the corresponding resistivities for some nominal inch thicknesses:
..031 in ---> 300 ohm-m ..062 in ---> 150 ohm-m ..125 in ---> 75 ohm-m ..188 in ---> 50 ohm-m"
I may have mis-interpreted this as meaning you are interested in current flow between electrode areas separated in the plane of the sheet. The resistance one would measure perpendicular to such a sheet will depend on the size and lateral displacement of the electrodes relative to the thickness of the sheet.
Perhaps your question was much simpler: if I had a material with a bulk resistivity of 75 ohm-m and gave you a piece in the shape of a ..125" thick sheet is that all you want? If so, how large a sheet? Flexible or rigid? Durable?
Yes, that's all I want. I would prefer sheets as large as possible...in roll form would be great. It doesn't have to be super-flexible, but I don't want it brittle like glass either. It will be applied to a slightly irregular surface, but generally planar...maybe sort of like a large airplane wing. It will not be subjected to much abuse, but it might be exposed to normal outdoor temperatures.
So far I'm leaning toward some conductive plastic sheet material that McMaster-Carr carries. But only because it's all I've found yet (and it only comes in 12" x 12" sample sheets". That's why I was wondering if one of you clever guys might have heard of something else that I missed.
You might try looking at some ferrite polymer material sheet stock, though most mfrs are only interested in surface finish resistivity of the treated material.
They are not designed for use as strictly resistive materials, so who knows what they would do over a range of temperature or pressure.
Where defined, published resistivity shows a range between 500 and 21 ohm-meter, below 10KHz.
In that case, try the conductive anti-static foam sheets (24 inch by
12 inch by 0.25 thick) that Jameco carries; part 13864 for $9.29 ea or $8.35 each @ 5. They roll it up for shipping. Measured resistance across diagonal with probes close to the corners, is about 8K.
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You might want to try:
http://www.advsys.com.au/downloads/cuming%20catalogue.pdf
In particular, Technical Bulletin 320-8 on page 67.
Also, Series Number 26200 at:
http://www.right-tape.com/html/prod_silicone_rubber.html#photo6
Also there are a lot of hits you might want to check out at:
http://www.google.com/search?q=electrically+conductive+rubber+sheet&hl=en&lr=&start=20&sa=N
Please read the frigging spec sheets, on the links provided, before commenting.
Polymer materials are available in sheets, rolls, or injection molding pellets.
The problem with filled polymers is dimensional instability - hence their use in pressure and humidity sensors and a restricted environmental range - and problems using them as a heaters. When deposited in thin fims on mechanically rigid formers, they have more common applications.
The usual method of producing conductive/resistive polymer is to carbon fill, but just try to locate a vendor of sheet stock with resistivity lower than the typical ESD dissipative ranges......
In that case, try the conductive anti-static foam sheets (24 inch by
12 inch by 0.25 thick) that Jameco carries; part 13864 for $9.29 ea or $8.35 each @ 5. They roll it up for shipping. Measured resistance across diagonal with probes close to the corners, is about 8K.
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