Wayne, Thanks but I had zero luck searching through the archives, probably pilot error. But I looked into IPC1601 and it did say "Air Flow is Critical". I wonder how that jives in a vacuum? I also saw some references to the need for air flow to heat by convention, that makes sense. Backout at 125C can degrade finishes so I would like to dry out PCBs in a dry box. I have seen info from McDry showing rates of moisture removal. Seems the times are about 10 - 30 hours at 30C. This data is for ICs, I am curious what might apply to PCBs. I would much rather dry at 30C for a long period of time than 125C. I am wondering if anyone knows of any data. Thanks, Bob K. -----Original Message----- From: TechNet <[log in to unmask]> On Behalf Of Wayne Showers Sent: Tuesday, September 11, 2018 6:30 PM To: [log in to unmask] Subject: Re: [TN] PCBs in dry chambers http://listserv.ipc.org/scripts/wa.exe?A0=TechNet this will also show the monthly archive tabs