Following from the EMPF HelpLine in Indianapolis, prepared by Hamid Farsad: An inert atmosphere will be helpful if you are planning to use low-residue (no-clean) fluxes. I personally prefer the full tunnel simply because most of the oxidation takes place in the pre-heat section. An inert atmosphere will reduce the rate of re-oxiadation. But one may want to consider the cost vs benefits of a full tunnel. One consideration which is very important in using low-residue fluxes is the flux application method. Flux should be applied in a controled manner. I recommend the use of spray fluxer over any other flux application method. You can contact us directly if your wish further discussion at 317.226.5616 or [log in to unmask] ---------------------------------------------------------- SUBJECT: Wave Soldering Machine DATE: 1995-12-15 17:27:48 FROM: [log in to unmask]@PMDF@MBIN01 TO: [log in to unmask]@PMDF@MBIN01 We are planning on replacing our wave soldering equipment in the very near future. We are also begining to specify PCBs with OSP instead of HASL coating. The equipment we purchase will probably have an inerting system. Our choices include full tunnel or contour inerting. Would anyone with experience using an inerting solder wave line please comment on the pros and cons of each type. Suggestions would be much appreciated. Thank You, [log in to unmask]