Hi 'rnowland,'
I do not think your problem is co-planarity, but insufficient heat; that 
copper heat sink works——well, like a HEAT SINK. Your QFP leads simply do not get 
hot enough—you are likely at the hairy edge, that is why some solder others 
not.

Regards,
Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL 32174 USA
Phone: 386-437-8747, Fax: 386-437-8737, Cell: 386-316-5904
E-mail: [log in to unmask], Website: www.engelmaier.com


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