Too cool and too dry. Maybe OK likes long shelf times. It's always a mystery. MoonMan ----- Original Message ----- From: Stephen R. Gregory <[log in to unmask]> To: <[log in to unmask]> Sent: Friday, October 08, 1999 6:03 AM Subject: Re: [TN] Shelf Life > In a message dated 10/07/1999 7:46:54 PM Central Daylight Time, > [log in to unmask] writes: > > << TechNet, > > I need to tap a little expertise from the assemblers out there.... > > I have a PWA kit to be built that has been sitting around for about 12-14 > months. > No environmental storage of any kind, just in tubes and boxes in the > stockroom. > What dilemma's am I likely to encounter with these components, if any?? I > suspect > the boards will need to be baked, but normal duration or more based on length > of time on the shelf?? Any worry about warp and coplanarity? > Any issues with components that have not been stored > with any dissicant or anti moisture protection? Any worry about lead > oxidation > that requires cleaning/tinning for solderability/wetting concerns? > > Just wondering what kind of interesting things to expect or try and avoid, > if any. > > Any suggestions or comments greatly appreciated. > > Tks......DT >> > > Hi Darrel! > > I don't know if this will help you or not, but about 3-weeks ago, I got the > pleasure of wave soldering some boards (about 2-dozen) that had been > partially assembled and had been sitting in tilt-racks for close to > 10-months! There was SMT on top, some PTH, and also had components epoxied on > the bottomside (passives and actives) as well! > > Don't ask me why they sat around that long...something about the project > being put on hold or something, I don't know. All I know is they brought the > boards to me and asked me to wave them. They asked before I waved, how did I > think they were going to do...I said probably like a pile o' poop, but I > didn't have anything to lose so I'd give er' a go. I baked them and then > waved them...used a OA flux. I musta' had the soldering gods looking over me, > they actually looked good! One of the supervisors came to look at the boards > while I was waving them to get ready for all the touch-up they were going to > do, but was amazed that they soldered as well as they did (I was pretty > shocked myself, but I didn't show it...kinda' smug actually) > > Don't know if you'll be as lucky as I was... > > -Steve Gregory- > > ############################################################## > TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c > ############################################################## > To subscribe/unsubscribe, send a message to [log in to unmask] with following text in > the body: > To subscribe: SUBSCRIBE TECHNET <your full name> > To unsubscribe: SIGNOFF TECHNET > ############################################################## > Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional > information. > If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or > 847-509-9700 ext.5365 > ############################################################## ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################