Siggi: What a great question, because it cuts to the heart of the issue. Unfortunately, it cannot be answered, for many reasons, not the least being that there is no absolute definition of any of the fluxes, they are defined by the vendors, who each have a slightly different concept of what is needed for a particular kind of flux. But, more, the difference between fluxes is less the amount of acid, than the strength of the acid being used. The rosin acids are very weak, and on the other end of the scale, some fluxes may even contain strong mineral acids like Hydrochloric, and Hydrobromic. So, the mg KOH/gram is a meaningless number. Great question. Rudy Sedlak RD Chemical Company --------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/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 -----------------------------------------------------