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Bit of a long shot here, maybe someone knows what the sticky clear gel might be inside common dual film can capacitors (motor run). I'm specifically looking for an MSDS.

This particular one was about the size of a soda can (dual 5uF/40uF 440VAC).

enter image description here

It is definitely not silicone grease- far more sticky and stringy (like hot glue when it is liquid) and has a slight odor. The closest thing we've seen is icky-pick used in telecom equipment. I have asked the manufacturer (American Radionics) but no answer as of yet.

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    \$\begingroup\$ All I know is that TDK endeavours to use Bio-degradable soft resins these days. 20 years ago it might have been a tougher brand of silicon based resins or petroleum based ones. It's usually a jellyfied resin of standard description I believe. Remember that silicone doesn't just come as grease, but also as hard resin, soft resin, jelly and glue (and all smell different too!). Anyway, I'm afraid every manufacturer is different. Best you can hope for is a response from AR or someone here who happens to (have) work(ed) for them. Hope you have luck with either. \$\endgroup\$ – Asmyldof Jun 25 '15 at 16:05
  • \$\begingroup\$ @Asmyldof Yes, this is in the 20-year-old region. I'm thinking petroleum based, it doesn't behave anything like any silicone grease or oil I've used (VERY sticky). At least it's not PCBs- specifically marked as not containing such. \$\endgroup\$ – Spehro Pefhany Jun 25 '15 at 16:15
  • \$\begingroup\$ The primary compound of my optically clear silicone waterproofing resin is sticky, but also strangely lubricating, it's a very weird sensation, so silicone can do that. I can also mention it is almost impossible to get off of wood flooring by means other than slipping over it with socks for a couple of months (many near-bruises :-) ). I only now think of lightly wetting a cloth with some hardener and rubbing it to see if it becomes a peelable sheet. Anyway, that's probably not it, but if the capacitor is high-temp rated it might contain some percentage of a form of silicone still. \$\endgroup\$ – Asmyldof Jun 25 '15 at 16:30
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    \$\begingroup\$ It's a quality part for a good U.S. manufacturer (York), so I'm not at all worried about it containing anything that wasn't legal in 1994. Seeing as the cap company is not answering maybe they are worried about something though. PCBs are not really that bad unless burned. \$\endgroup\$ – Spehro Pefhany Jun 26 '15 at 15:14
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    \$\begingroup\$ They're still not super awesome when not burned, though. \$\endgroup\$ – Asmyldof Jun 26 '15 at 16:26
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It's capacitor gel. Electrolyte. Here are typical capacitor safety sheets:

http://www.ioxus.com/files/8714/3681/1244/Ultracapacitor-MSDS-02-06-2013.pdf

http://www.rpiparts.com/ds/CMC042msds.pdf

Note the ingrediants: Boric Acid/Ammonia, and Tetraethyl-Ammonium-Tetrafluoroborate/Acetonitrile.

There is no way of guessing what the electrolyte in a capacitor contained. You have to find out what the manufacturer was using at that time.

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  • \$\begingroup\$ David This is a run capacitor (or so it was stated) so it wouldn't be an electrolytic. Electrolytics have too high a loss for continuous operation. \$\endgroup\$ – Robert Endl Jul 21 '16 at 7:43
  • \$\begingroup\$ One of their patents identifies the "oil" as "Polyurethane Oil ". No idea what that is. \$\endgroup\$ – Robert Endl Aug 20 '16 at 7:37

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