Wow, Thanks to everyone for all the info. I have a new update. We tried 4 things based on a number of recommendations: 1. Applied flux and hit the area with an iron. The discoloration went away. But, we have such a large area on so many boards there is no real way to get this done in a timely fashion. In addition, we scratched the area up pretty well, so, either way, it looks bad. 2. We tried to re-wave the board. The discoloration got whiter/hazier 3. Used Methyl Chloroform to test for permanency. No mask was evident on the swab which tells me the mask is cured. 4. Lastly, we baked a board at 250F for 45 minutes -- no change. So...Any ideas what it is or if it is detrimental? Any suggestions? It's Friday...If anyone can suggest the boards are OK and I can feel comfortable to ship that would be fine by me. -Carrie -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Gregg Klawson Sent: Friday, April 23, 2004 11:50 AM To: [log in to unmask] Subject: Re: [TN] White Discoloration -- Excessive Heat, Insufficiently Cured SM, or, Both? Carrie, Some info from one SM mfr, this may help. http://www.enthone.com/electronics/pdf/Imup5.pdf -- Gregg At 02:27 PM 4/22/2004, Morse, Carrie wrote: >Here's the status. I baked the boards for 45min @ 250F and...I still >have the white haze. No change. So, What do you all think? >(IOW--HELP!!!!) > >-Carrie > >-----Original Message----- >From: Brian Ellis [mailto:[log in to unmask]] >Sent: Thursday, April 22, 2004 2:06 AM >To: TechNet E-Mail Forum.; Morse, Carrie >Subject: Re: [TN] White Discoloration -- Excessive Heat, Insufficiently >Cured SM, or, Both? > >I'm not saying that this is the cause, but another possibility is >hydrolysis of the uncured solder mask. If the boards are coated and >then stored in a humid atmosphere before development (either before or >after >exposure) for more than an hour or two, then some components in the >chemistry may absorb sufficient humidity to hydrolyse, partially >upsetting the polymerisation. > >I suggest methylene chloride would be better than acetone for a wipe >test, but it depends on the chemistry of the LPI. > >Brian > >Morse, Carrie wrote: > > We are wave soldering a LPI board and seeing a Whitish Discoloration > > -- Haze like -- only in the areas that the board has seen OA flux > > and >wave. > > We are using a wave pallet and the areas not exposed do not exhibit > > this phenomena. This board is also processed through SMT for one > > side > > > and we do not see this around any of the SMT. > > > > We have not seen this problem in the past, and, the Wave operator > > states that the wave recipe has not changed. > > > > So, I am wondering -- if LPI is not fully cured, will it turn white > > when exposed to OA flux and Wave? > > Also, what IS the max temp LPI should be able to see and for how > > long without discoloring? > > We've done an Acetone test, but, it comes up clean and....I think I > > read in a previous posting that the Acetone may not be an effective > > test for LPI. Is that true? If so, What IS an effective test? > > > > I'm headed to the Omega tester to see "how clean" the board is. > > > > All advice is welcome! > > > > -Carrie > > --------------------------------------------------- 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 -----------------------------------------------------