Actually I have two questions.
1)  Does anyone have data showing the effect on solder joint reliability of
a twice re-flowed BGA?   A client is considering a board design with BGAs on
both sides and is concerned about the reliability of the solder joints on  a
BGA placed on the first side because it would be exposed to two reflow
cycles. Has anyone done this and followed up with any long term studies?
Would a second application of flux be useful ?
2)  This one is more straight-forward.  Where can I buy a 'tack-roller' for
cleaning solder paste from the bottom side of stencils?   Even the best
'lint free' wipers tend to shear and leave tiny shreds on the stencil.
Thanks in advance, Rod Lafond
                                  Manufacturing Engineering
                                  Aimtronics, Delta B.C.

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