Doug Citric acid is a funny one. It is tribasic (compared with dibasic for most of the other usual N/C activators). Hughes are not the only one to come unstuck with citric: Zeva had a citric acid/glycerol (a triol or tribasic alcohol) W/S flux in the 1970s, long before Hughes. I believe that the problem with citric is that it forms unstable chelates with some heavy metals (don't drink lemonades etc. from lead crystal or lead-containing pewter vessels!). The later formulations were, I believe, with maleic acid (found in green apples), which is dibasic. Its ages since I heard anything about HF fluxes: I thought they had died a natural death. I had a really bumper crop of lemons this winter, so my personal citric to maleic ratio has increased enormously :-) Brian Douglas Pauls wrote: > > Very interesting, Jim. Do you happen to know who made the HF series of > fluxes? I would like to get data sheets on them. > > The original HF1189 was based on citric acid (lemon juice) as the > activator. The HF stood for Hughes Flux. When it first came out, it was > hailed as the greatest thing since sliced bread. A classic case of a > marketing department gone amuck. The citric acid can be corrosive and > there were some memorable military failures as a result. Several studies > were done on the 1189. > > I believe Kester picked up the 1189 family. They reformulated the > activator away from citric acid toward more benign weak organic acids and > called it HF1189A. If I recall, the 1189A contains no citric acid. > > I suggest you contact Kester for more information. > > Doug Pauls > Rockwell Collins > > --------------------------------------------------------------------------------- > 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 ---------------------------------------------------------------------------------