Graham, I have had a couple of job estimates where the requirement needed the use of the Parylene Conformal Coat. This is what I know about it. 1) My only contact has been through SCS, Hans Bok, out of North Dartmouth, MA 800-356-8260. 2) There are 3 different grades of parylene, Parylene C, D, and N. Class C is for electronic boards. Company literature elaborates very well on the physical properties of each. This is a vacuum deposition process. Place items in a vacuum chamber. Pump the system down, 3 sections, The coating material , a dimer, goes through Vaporization, Pyrolysis, and Deposition. Totally automatic process. Again, company literature explains the process nicely. 3) Two machines available, a lab type machine costs $25K includes chiller. It has a 21 liter chamber. This is a batch type process, fit everything you can into the chamber, without touching. Takes about 6 - 8 hours to apply a 0.5 -1.0 mil coating. Holds a quarter pound of material. Material is about $440.00 /lb. 4) Production level machine costs $65K without chiller. (Note: the chiller is needed to keep the parylene from depositing itself into the vacuum system.) It has a 63 liter chamber. Production time is dependent upon vacuum pump down time. At equilibrium, deposition occurs at 5 microns/hr. 5) If you have a small volume. I suggest you send out and have this done. 6) Masking of the item to be coated sounds to me like the biggest challenge. Do not plan on being able to remove this coating unless the use of a band saw is in your arsenal of printed circuit board rework tools. (We don't allow our operators to use a band saw for rework, [TIC]) Seriously, what I'm saying is that, if you have masked off a round circle dot, you have to cut through the coating to lift the dot off. I don't know what you might do if you have to mask off areas with traces. Trace damage is almost a certainty. 7) This is the thinnest and the hardest coating I've ever seen. Do not plan on being able to rework. Good Luck, call me if you have questions. I hope that I've been of some help. Bill Kasprzak Moog Inc. 716-652-2000 ext 2507 ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################