Bryan, We use Humiseal 1B31 and we do not have these problems. I'm not sure if you can consider a switch or not. A good resource is www.humiseal.com. Eric Kalgren BFGoodrich Aerospace Data Systems Division >>> Bryan Kerr <[log in to unmask]> 07/07 2:39 PM >>> Hi all, Any experiences with Humiseal 1B73. I'm finding it tends to pull away easily from a solder resist surface, particularly on boards with heatsinks, along the edge of the heatsink profile. Thermal cycling makes it much worse. Any similar problems out there ? Bryan