In reply to the below message. Make sure that you do not have a tight seal around the Top side of the PWB with some components especially if they are barrel type electrolytic capcitors. Seen this happen in the past. Ivan Date: Wed, 31 Oct 2001 22:49:32 -0800 From: PL <[log in to unmask]> Subject: Blow holes in solder joints Hello, I would like to ask your input on trouble shooting a wave soldering process that I've encountered producing blow holes on the PCA. The blow holes were seen at random locations, mostly on small and light caps. The boards were manufactured in recent weeks. Some board warppage was noticed after the wave. Things I tried: - Boards from a different manufactured date, no effect - Turned on turbulence wave. It reduced but didn't completely eliminate the defect - used stiffener on board edge to reduce board sagging - used dummy weights on top of parts seen having defect to minimize "dancing" during wave How critical is the component lead-to-hole ratio as far as its impact on solder joint quality? Could anyone explain how a blow hole can occur and possible steps taken to eliminate the defect? Rgds, Peter