I've run into this problem several times. You are setting up a galvanic reaction between the gold and copper causing the copper to etch faster. I've solved this two ways. 1. If possible tape the tabs or gold area completely. This prevents the reaction but involves a good deal more in handling. There is also the tape residue. 2. Preclean the panels utilizing a non acidic cleaner. I use a Hyoki with an aluminum oxide grit. Test your panels to determine best speed and pressure as well as to see if the boards hold up.Clean your panels then go into whatever process you are doing. I have found the 2nd method to work the best. Even with soft gold I've had no problems with reducing the gold thickness. ______________________________ Reply Separator _________________________________ Subject: [TN] Micro-etch attacking copper when gold tabs are involved Author: Franklin <[log in to unmask]> at smtplink-hadco Date: 10/8/99 2:51 PM Okay brainiac's, here's a stumper. We are witnessing micro-etch attacking exposed copper circuitry only on boards with gold tabs. This occurs right at the copper to gold demarcation point. This only just started, within two days. No significant process changes have occurred. (normal replenishments, all data looks nominal) We first noticed it after we stripped off some poor white tin for rework. When we inspected the boards before the second trip through immersion tin, we saw reduced circuits, some to the point of non-existing, pads etched away far beyond anything the micro-etch should be capable of in the seconds we keep product in this bath. From our supplier, they believe the gold is reacting with chemistry in the micro-etch bath?????? Has anyone else witnessed this? And how'd you resolve it? Thanks, Franklin