Ivo - We are just completing a low residue flux implementation program and eliminating all rosin fluxes from our manufacturing process. We are a military/commercial OEM but convincing our customers wasn't easy. Quite a bit of test effort went into the selection of a low residue flux that is "cleanable" and "as good as" our former RMA flux. We will be removing our flux for a period of time then work with our customers on the next step - implementation of a no clean process. When you talk to your flux manufacturers you need to point out that you want a "washable" low residue flux - don't just request a water soluble. There still seems to be a terminology problem - many people use water soluble and water removable flux as equivalents. They are not! Many of the low residue fluxes are modified rosins and not the water soluble type fluxes that you are familiar with. Throughout our conversion program I have run into another terminology issue: low residue and no clean. Low residue is a material characteristic of a flux, no clean is a manufacturing process choice - these two terms get used interchangeably also. I would contact Doug Pauls at Contaminated Studies Labs 317-457-8095 or [log in to unmask] on what typical tests are being used for rosin-to-low residue flux conversion programs. Good luck. Dave Hillman Rockwell Collins [log in to unmask] ______________________________ Reply Separator _________________________________ Subject: ASSY non-rosin flux and MIL Author: [log in to unmask] at ccmgw1 Date: 5/8/96 4:31 AM Thinking obout the environment and all, a solder paste that can be cleaned after reflow using (DEMI)water is a beautiful thing. However, when i'm thinking about using it, questions bubble up... Water-washable fluxes in solder pastes are always? non-rosin (for example organic acids). Because my fab produces many militairy PB's, this is unaccceptable. Only R and RMA are conform the the good old MIL-STD-2000. (Or you may only solder sealed devices etc. and still meet some conditions) OK, flux activity of these paste are higher, but the modern OA flux-types are comparable with RMA? An other problem is that "Flux residue or foreign material" is a defect (acc. to the 2000). Cleaning SMT, even with low residue/no clean flux becomes very difficult that way. Especially when i consider that ionic contamination test equipment for THT is not adequate for SMT. And when coating the PB's, the less residue the better. Mixed THT/SMT products are also food for thought. Can someone help me see the light? Any statement, suggestion or experiences using "aqua" pastes and cleaning/coating them after reflow FOR MILITAIRY USE are welcome! (MIL-STD-2000 is still our guideline) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Ivo de Rooij Process Engineer SMT/THT Fokker Elmo BV (Fokker Aviation) [log in to unmask] .