From what you're saying I would try a fresh paste container as received and see what happens. WS pastes can be effected by moisture take up, but a new jar fresh from the supplier should be OK to start. If the incidence is unchanged then you will have at least eliminated this from your investigations. Water take up by the paste will result in it steaming and spattering the solder into small beads around each joint area. If it is moisture uptake into the paste and you continue to use it then you can run into other problems as the water content becomes more significant. We have a short leaflet in which the issue of Solder balls/beads is defined and addressed. If you would like a copy let me know off net. Best regards Mike Fenner Applications Engineer, European Operations Indium Corporation T: + 44 1908 580 400 M: + 44 7810 526 317 F: + 44 1908 580 411 E: [log in to unmask] W: www.indium.com Leadfree: http://Pb-Free.com -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Jorge Rodriguez Sent: Tuesday, August 21, 2001 7:57 PM To: [log in to unmask] Subject: [TN] Solder Beads (not solder balls) Fellow technetters, We are having tons of issues with solder beading, even on boards were we didn't have the issue before. We're clueless, we suspect of the solder paste (63-37 Water Soluble), it looks slumpy amd watery, but we're not sure. I know solder beading can be solved by designing the stencils with home-base aperture, but what we're seeing here is across the board, not just one particular assembly but several. Does anyone have experience dealing with an issue like this?, could solder beading caused by the oven profile or is it more like solder paste related? Any comments would be appreciated. Jorge Rodriguez Process Engineer Varian Electronics Manufacturing E-mail: [log in to unmask] ---------------------------------------------------------------------------- ----- 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 ---------------------------------------------------------------------------- ----- --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------