What is a good flux solvent
T Chap
Posts: 4,223
Just started converting some projects to all SMT, and experienced that on a few boards that have traces underneath the IC, some flux is not completely getting removed when I clean the boards with water. I just started using flux to solder in one tssop .5mm part separately from the others, and it has traces underneath it till I can redo the board design. When flux remains stuck under it, and 27 volts from one of the traces hits the flux, tiny sparks come out, and the chip is done. The flux cleaner I have is brutal, it really makes the boards a mess. I need some type of nondestrucitve solvent for the flux that stays jammed under the IC. Anybody got any suggestions?
Comments
The solvent you use depends on the type of solder paste or flux that you're using. Check the solder paste data sheet or flux for the recommended solvent.
Aqueous flux is best removed with warm water. You should be able to immerse the board for 1-3 minutes in warm water, brush it with a toothbrush and rinse with clean, deionized water and blow dry with air.
RMA or Rosin flux can be removed with a saponifier mixed with water or isopropyl alcohol. Immerse in isopropyl alcohol for 1-3 minutes and blow dry with air.
No-clean flux hardens after exposed to heat and typically doesn't need to be removed after soldering. You should minimize the amount of no-clean flux used as unheated no-clean flus IS slightly conductive!