I waited to see if you got any replies on this before adding my twopenneth as I can really only offer anecdotal advice. It is theoretically possible for acid [flux residues] to "attack" welds in otherwise uneffected metals. The discontinuities in the metal structure at the weld can be sufficient to cause reactions similar to the effect when an acid is in contact with two different metals at the same time. This is particularly the case if you have welded an alloy as opposed to a pure metal, and if the flux is a powerful one. However I would think the probability of this happening is slight with electronic - ie weak- grade fluxes . Certainly it can be a problem with brazing fluxes (which are hundreds of times more active). How to find out more and what to do? I suggest you ask these people for documentary evidence or references to support their contention. That will give you a start point on finding the answer to your posting. In the short term tcan you use a spot mask, [peelable or washable] to avoid flux contact, this will either give you a fix and time to think for a long term answer. (eg have the assemblies plated). Or it will show the problem is elsewhere. If it looks as though there is any substance in this, to actually determine if this is a problem you will need to do some proper metallurgical investigations and maybe even some ageing trials. Here you enter the realms of theology as the accelleration needed in the ageing may kick off events that would not actually happen in real life. I guess what I am saying is you would need specialist advise, somone like the International TIn Research Institute, TWI etc. .................................... In a message dated 11/01/99 09:06:48PM, you write: > am attempting to find some info or a standard that deals specifically with > the soldering of purely mechanical parts, ( a tube used to transfer > hydraulic fluids in an electro-mechanical assembly soldered to another > transfer tube) , the company thinks that the small amount of acid from the > flux core solder is over a period of time weakening the "weld" and resulting > in cracks or fractures. Can anyone help me with this one? Thanks in > advance. > > [log in to unmask] ################################################################ 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 ################################################################