Dear Wee Mei As implied by David Douthits message, the coating has become "soft". This may have allowed certain particulates to "adhere" to the surface - they are not likely to "sink-in"! These coatings are "thermo-plastic" materials, so this condition is not surprising but, the coating is NOT becoming liquid. If this issue cause you some reliability issues - the assembly is failing in test or real conditions because of this condition - then you might like to try another variant, details of which I will give you off-TechNet. It is simply another acrylic material that has a different thermal withstand that permits it to be less "sticky" under high temp conditions. If you are NOT getting failures in test or service, is there a problem? Regards, Graham Naisbitt [log in to unmask] www.concoat.co.uk <http://www.concoat.co.uk> For instant access to Product Data Sheets register on the Tech-Shot area of http:// www.concoat.co.uk <http://www.concoat.co.uk> Concoat Limited Alasan House, Albany Park CAMBERLEY GU16 7PH UK Phone: +44 (0)1276 691100 Fax: +44 (0)1276 691227 Mobile: +44 (0)79 6858 2121 -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of fullname Sent: Tuesday, September 25, 2001 08:34 To: [log in to unmask] Subject: [TN] Dirt on Coated Board (UC) Some assembled boards were coated with Humiseal 1B31. After the ESS tests at 110 degree C, dirts were found on the board and component surfaces on both sides. I have checked the data specification on 1B31 and found that under cured enivronemnt, the coating should withstand -65 to +125 degree C. Can someone advice me what could be the cause of this problems? Your assistance is greatly appreciated. Regards - Wee Mei ---------------------------------------------------------------------------- ----- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------- ----- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------