In a message dated 4/9/99 12:47:55 PM Pacific Daylight Time, [log in to unmask] writes: << You would use "sticky flux". The same viscous flux that is used in solder-paste. Contact your Solder Paste Vendor. My impression is they all sell the stuff now for BGA and flip-chip attach. It is often applied to the BGA balls by dipping the BGA into a controlled thickness of flux that is squeegeed onto a surface plate or squeegeed directly onto the board with a stencil. The BGA attach is done with no-clean for very fine pitch balls. I don't work at an assembly shop but I believe I've described is actually being done. >> Yep Gary... Fer not working in an assembly shop you hit the nail on the head. Actually, it's just a paste flux. Kester and Alpha both make it as I imagine other suppliers as well. I believe that for the PPT process they had their own formula and had added "Tackifiers" to it to make it a little more tacky than regular paste flux. You're also right about the BGA stuff too. If you've ever heard of SolderQuik (Russ Winslow shows up on the TechNet a lot, he's from SolderQuik), paste flux is what's used to re-ball BGA's with their preforms (which are the neatest thing since sliced bread by the way)...and speaking of bread, when solderquik had their booth set-up at SMI last year here in San Jose, they used a convection "Bagel toaster" to re-ball BGA's to show how simple it was. Snicker if you want to, but it worked like a charm! -Steve Gregory- ################################################################ TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################