Graham, Do you have access to the study results from NPL? I would like to see that study. I would like to know what the effects are of too much/little flux applied. Also, do you know how flux density plays a part in solder joint reliability? Thanks in advance, Rob Watson Sanmina Corp. Plant 10 Durham, NC Graham Naisbitt wrote: > Neil, > > I presume from your posting that you are not cleaning after soldering. > > I would strongly recommend that you try and keep the amount of flux applied > under some control. As all fluxes leave residues, the way in which these > react can lead to unpredictable or at least undesirable reliability issues. > > The NPL in the UK have completed a study which shows the amount of flux > used, grossly affects reliability. > > Of course if the product is of low consequence then this may not be > relevant. However, if you are producing something that is HiRel or Safety > Critical, then maybe it is relevant. > > Might be a good idea to then validate your production process to yield the > best results and then keep it under control. Try IPC-J-STD-001 Appendix > D.Regards, > Graham Naisbitt [log in to unmask] Concoat Ltd > Alasan House, Albany Park > CAMBERLEY GU15 2PL UK Tel: +44 (0) 1276 691100 Fax: +44 (0) 1276 691227