Asphalt has been used as a potting compound for a long time. I did not find it in UL1012 but below is a reference in UL8750 (LEDs). I believe if you ask your UL project engineer (or their reviewer if he’s a 20 something engineer) you’ll find asphalt is acceptable without it being UL R/C. Surely someone on this listserve has used asphalt as an insulator before.
6.7 Potting compound 6.7.1 Potting compound shall not leak, drip, or be released from a unit while under condition of testing, and shall not exceed its Relative Thermal Index (RTI) during the temperature test of 8.3. 6.7.2 Asphalt potting compound shall remain at least 15°C (27°F) below its softening point as determined by the Standard Test Methods for Softening Point of Resins Derived from Naval Stores by Ring-and-Ball Apparatus, ASTM E28. John Allen President Product Safety Consulting, Inc. 605 Country Club Drive, Suites I&J Bensenville, IL 60106 P - 630 238-0188 / F - 630 238-0269 1-877-804-3066 [email protected] http://www.productsafetyinc.com Although PSC maintains the highest level of virus protection, this e-mail and any attachments should be scanned by your virus protection software. It is the responsibility of the recipient to check that it is virus free. PSC does not accept any responsibility for data loss or systems damage arising in any way from its use. This message is confidential and intended only for the individual to whom or entity to which it is addressed. If you are not the intended recipient or addressee, or an employee or agent responsible for delivering this message to the addressee, you are hereby notified that any dissemination, distribution, or copying, in whole or part, of this message is strictly prohibited. If you believe that you have been sent this message in error, please do not read it. Please immediately reply to sender that you have received this message in error. Then permanently delete all copies of the message. Thank you. From: IBM Ken [mailto:[email protected]] Sent: Monday, January 03, 2011 4:07 PM To: [email protected] Subject: Re: [PSES] Potting material I don't have any experience with UL 1012 but I am fairly certain UL and CSA wouldn't let me use asphalt for potting in a 60950-1 product (why? I don't know). The few times we used either a conformal coat or potting process, I believe it (the material and the process itself) was Recognized under UL 746C. You could try using the UL Yellow Books to look for suppliers under the CCNs that produce 746C Recognized products. -Ken A. On Mon, Jan 3, 2011 at 3:59 PM, Carl Newton <[email protected]> wrote: List members, I have no direct experience with potting materials. I have a power supply installed within an extruded aluminum casing and we need to pot the assembly. The epoxy potting materials are relatively expensive. It's our understanding that asphalt is commonly used in light ballasts and that it is much less costly. I'm taking this assembly to UL for compliance with UL 1012. If any of you can point me in the right direction I would certainly appreciate it. I'm a pretty fair googler but I'm not having a lot of luck finding any asphalt potting suppliers. I got one potentially valid hit in the UL database but it's a Korean source with no apparent USA distribution. Please feel free to contact me offline if you like. Thanks in advance, Carl - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://product-compliance.oc.ieee.org/ Graphics (in well-used formats), large files, etc. can be posted to that URL. 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