I've had to do many jobs like this, and I agree that chemically is definitely the wrong way to go. A hot air jet can be pretty effective: you hold the jet in one hand and scrape with an xacto using the other. Need very steady hands and you'll probably get a few fingertip burns, but it is effective. Just be careful of the board material. Believe me, I have done similar work at tighter resolutions than your job. You need a good stereomicroscope, lots of hand supports, and controlled breathing. If you have a bunch of these to do, the laser might be good, but don't dismiss just plane old mechanical machining. Mill bits are available standard down to 5mils in diameter, and a real good machinist can get the unwanted material reduced to about 0.001 inches thick, which is usually pretty easy to scrape off. The advantage is that no heat is required. The dis-advantage is the fixturing is kind of a pain to build, but good machinists can do it. Wayne Thayer >>> [log in to unmask] >>> A couple of other things about Tetrahydrofuran. Exposure to the chemical has been well covered. However, the TLV of exposure in the US is still high for the properties outlined for Europe. 200 ppm is pretty high, but my guess is that will be lowered. Anyway, the internet says a million pounds a year are used in the US. THF is an excellent solvent, as Rudy has pointed out. I cannot imagine it will just attack parylene, and not attack the epoxy of the board, solder mask/marking inks, and potting compounds on your discrete components from the picture of your module. Some of the other solvents Rudy offered you are either the stuff for dissolving epoxy so it can be coated on to glass fabric, or the solvent used in the multilayer PTH line for removing epoxy drill smear. Finally, THF is pretty flammable. I did not look up ethyl ether, but if you use it, pretend you are using starter fluid for a gasoline engine. Denny Fritz MacDermid, Inc. --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------