Joseph, I am not particularly fond of AR type coatings for class 3 products for the following reasons: 1. Low Tg, from 15 to 40 degrees C 2. As mentioned most forms of hydrocarbon based solvent (and their fumes) can desolve/liquidfy the coating. Depending on the end use environment these items can pose serious problems! I suggest you get a copy of the IPC-HDBK-830 (Conformal Coating Handbook) before you decide. David A. Douthit Manager LoCan LLC Kane, Joseph E wrote: >We're Class 3, mostly military aircraft electronics. >Historically, we've used Type UR, but we've recently >brought in some work from another plant that has >been using acrylic. We're in the process of switching >everything over to our UV-curable urethane for the >following reasons: > >1. UV-curing saves a whole lot of cycle time. The >acrylic must be air-dried or baked. > >2. In order to perform any rework at all, you must be >very careful when removing coating in particular spots, >and things can look pretty ugly after recoating. More >often than not, we end up stripping and re-coating the >whole thing. More lost time. > >3. Some of our designs require solvent-resistant coating. >If we're going to settle on one type of coating, it might >as well be urethane. > >For the record, we haven't noticed any compatibility >issues with the fluxes and solder masks that we've been >using. > >Of course, YMMV. If you're doing occasional touchup on >a solder joint or two, Type UR may be preferred. If you >need to replace a lot of components, it's probably easier >to strip the coating and start over. > >-Joe > >-----Original Message----- >From: - Bogert [mailto:[log in to unmask]] >Sent: Monday, March 08, 2004 4:55 PM >To: [log in to unmask] >Subject: [TN] Pros and Cons on Type UR vice Type AR Conformal Coating > > >As a Class 3 customer we are considering mandating transition from Type UR >to Type AR conformal coating, to make it easier to replace failed >components. Are there any Class 3 users of Type AR coating? What is track >record for using Type AR? Are there any compatibility issues with certain >types of solder masks? Any input you have would help. Another advantage >with AR would be for returned equipment. The OEM could remove all the >coating from an assembly using alcohol, then perform >--------------------------------------------------- >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 >847-509-9700 ext.5315 >----------------------------------------------------- >bed-of-nails testing to quickly identify failed components. > >--------------------------------------------------- >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 847-509-9700 ext.5315 >----------------------------------------------------- > > > > --------------------------------------------------- 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 847-509-9700 ext.5315 -----------------------------------------------------