Bob, Sorry to dissapoint you, but dip coating never puts on an even coating on PCBs. The coating can puddle on the "top" side of all components as the PCB is removed. This then can drip to the "bottom" of the part and hang there during cure. The last edge to exit the tank is usually thicker than the top edge. The coating can just drip down to the bottom before it cures. Varying the withdrawal rate, coating viscosity, cure rate, exit direction, PCB orientation and panel cleanliness can all affect the above effects. Do your darker areas fall into the above categories? ARIC PARR Sr. Manufacturing Engineer Eaton Corp 1400 S. Livernois P. O. Box 5020 Rochester Hills, Mi 48308-5020 [log in to unmask] 248 608 7780 Fax: 248 656 2242 ------------- Original Text From: C=US/A=INTERNET/DDA=ID/TechNet(a)IPC.ORG, on 3/5/99 11:41 AM: To: Aric Parr@01635@Lectron_RH, EatonWHQ@CorpMail@WHQCleveOH[C=US/A=INTERNET/DDA=ID/TechNet(a)IPC.ORG], Luis Arevalo@Automotive Eng@AACOCarolStrmIL Good Morning, I am the QC Manager of Endicott Research Group, Inc in N.Y. I have some questions regarding the coating requirements located in the IPC610A Rev B (amendment 1 included). We are using a acrylic polymar coating with flourescent tracer materials. The question I have is that when we view the material under a black light we notice that some areas are heavier than others. The units are being dipped into a pan of material. I have reduced the amount of thinner used with the acrylic and the coating appears more even but heavier. Does the tracer have to be even? I would think being dipped that the consistency is the same. We have stirred the material to assure that the thinner wasn't seperated from the acrylic. Any input you can give is appreciated. Thanking you, Bob Arciolla ################################################################ 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 ################################################################