Replying to my own post here: I'm not sure if the original post made it to the list but I checked pricing on Ultem1000. The 1/32" x 24" x 48" plate material cost $65/sheet, so regardless of it's seemingly excellent cap dielectric properties, it's too much for this guy. The costs of these materials is probably why prof. manf. cap companies still use polypropylene or polyethylene materials. Bart
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- To: Tesla List <tesla-at-pupman-dot-com>
- Subject: Ultem as dielectric for flat caps?
- From: "Barton B. Anderson" <mopar-at-mn.uswest-dot-net>
- Date: Mon, 08 Dec 1997 22:07:42 -0600To all, Has anyone heard of Ultem Polyetherimide? I was looking through a catalog from Polymer Corporation and came across "Ultem" which has some very interesting properties. Here's some of the most interesting specs: * Dielectric Strength: 830V/mil * Dielectric Constant: 3.15 * Dissipation Factor: 0.0013 Some of the key benefits as stated by Polymer Corporation are: * High heat resistance * Exceptional flame retardance - UL 94-V-O rated * Exceptional chemical resistance * Low smoke * High dielectric strength * Low dissipation factor * Stable dielectric constant * Outstanding mechanical properties * Excellent machinability * Transparent (Amber) * Performs in continuous use to 340 degrees F It comes standard in 24" x 48" plates with a thickness range of 1/32" through 3". Has anyone tried this material before or know anything about this poly? It seems from the specs that it would make quite a dielectric. The cost might be inhibitive. Polymer Corp. grades their polymers with "$" signs. The range is $ to $$$$$, with Ultem rated at $$$. Maybe worth asking for quote? Bart Anderson
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