Hi, Pat, HMP solder has a melting point about 100 degrees lower than your example for electronics. Depends what you are soldering, but most components have an upper temp limit for the dies around 230 deg C and a few go to 250 deg C. Beyond that you risk internal damage. In-service temperature excursions depend on the operating environment and are limited by, and to, the rating of your components. Commercial parts are rated between -20 deg C (at best) and +70 deg C. Industrial parts are rated between -40 deg C and +85 deg C, while military parts are rated between -40 deg C and +125 deg C. Outside of these temperatures, the components may work, but their specified performance is not guaranteed. They should not see temperatures approaching soldering temperature in operation - they definitely wouldn't survive for long at that. Temperature settings for soldering should be 20 to 30 deg C above liquidous, but watch out for the max case temperature of the components - you may be getting pretty close to that with these settings. You will have to tread a fine line between peak temperature and its duration to get the boards to solder without damaging the component dies. Good luck Peter Duncan "Diamond, Pat" <PDiamond@WESTO To: [log in to unmask] NAERO.COM> cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Sent by: Aero/ST Group) TechNet Subject: [TN] Solder temperature question <[log in to unmask] G> 11/13/01 04:17 PM Please respond to "TechNet E-Mail Forum." /Dear all, I'm looking for some advice on the threshold limits for solder temperatures, if for example, HMP solder is solidus/liquidus at say 296-301 deg C, what is the highest temperature excursion it can see in service before the properties of the soldered connection are affected? I heard somewhere that as a rule of thumb you should allow around 40 deg C below the melting point of the solder being used. Any help/advice that you can give would be appreciated. regards, Pat Diamond Weston Aerospace Farnborough UK --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 --------------------------------------------------------------------------------- [This e-mail is confidential and may also be privileged. If you are not the intended recipient, please delete it and notify us immediately; you should not copy or use it for any purpose, nor disclose its contents to any other person. Thank you.] --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------