Wes, I have been involved with many customers changing over from an alcohol based no-clean to a VOC-free process. The change-over can be made easier by such things as air movement, convection preheat, "drains" or reliefs in pallets (if used), controlled deposition of flux, and temp profiling as described by Chrys Shea (you GO Chrys!). I have also seen a benefit in hitting the first preheat a little hotter, this drives off the vehicle (water) faster and leaves the solids in the preheatlonger in their active temp region. This is of course is a balancing act since you must watch your delta T especially if SMT components are on your ssemblies...USE YOUR MOLE/datapak! Some additional info would be helpful, what type of preheat do you have? how many zones? what type of w.s. machine do you have? what's the board material (paper, fr4)? Do you use pallets? What type? what fluxes are you trying? Feel free to contact me at 914-795-2020 or at email@example.com. Good Luck; Vince Whipple ps. I have spoken w/Chrys recently, she's a very good resource on these matters!