Steve, I agree with Ramon. Micro blasting is very effective. You also have the advantage that the parts are PTH. They have a relatively large solder volume that may be sacrificed. Cut into the solder volume with an Exact-o or even a fine dentil drill. Once a "hole" has been opened in the parylene, I have found that the burn technique is much more effective. Stick the solder iron tip in the "hole", once the solder is melted, gently rub the solder tip all the way around the lead to burn of the coating on all sides. -Mike -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Dehoyos, Ramon Sent: Friday, April 21, 2006 7:30 AM To: [log in to unmask] Subject: Re: [TN] Parylene Coating Removal... Hi Steve: Micro blasting will not damage the components next to it. You can remove the coating off the solder joints only with no problems at all. If you still have any concerns, all you have to do is to tape mask adjacent components. I am partial to CCRCo media due to its cleanliness and ESD safety. Nozzles to remove coatings come in all different sizes. For this board, use a small tip. The process is fast and inexpensive. Regards, Ramon -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory Sent: Thursday, April 20, 2006 5:18 PM To: [log in to unmask] Subject: [TN] Parylene Coating Removal... Hi All! I've always thought that when it comes to removing parylene coating, about the only way you can remove it is with some sort of mechanical means, i.e.; microabrasion, or scraping. Burning through it with a soldering iron when trying to do rework it is very, very difficult...I've tried it...it doesn't work well at all. I was just told that a chemical that I haven't heard of before might work, it's called THF, or Tetrahydrofuran. I was told that it won't dissolve the coating, but will cause it to lift from the PCB where it can be brushed away. Have any of you ever heard of this stuff? I'm not a chemist, and I'm not about to use it until I learn more about it. The issue that I have is with a little tiny assembly that has been built and parylene coated with some bad programmable hall effect switches installed. The board is so small, and there are other components installed really close to where the coating has to be removed. I'm afraid of getting them microblasted because I'm afraid of damaging the other components. See the assembly at: http://stevezeva.homestead.com/files/8001_assy_backside.JPG ...the small components are 0402's, so that gives you a visual scale of how big the assembly is... I've got the information in to a company that I found that does laser ablation to remove coatings to give us a quote, so I'm waiting on that. But if that turns out to be really expensive, I was contemplating using the THF as plan "B" (provided the stuff will work and it doesn't hurt anything else on the assembly). Kind regards, -Steve Gregory- Senior Production Engineer OAI Electronics East 12th Street Tulsa, Oklahoma 74112 (918) 836-9077 Ext.-507 (918) 706-2779 CELL --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------