A. Stack cut no less than 3 pcs. of 1/8" BB. The bottom piece is assumed to be a throwaway but I almost always manage to salvage mine.
B. For portraits with delicate areas I never use the blue painters' tape under the pattern.
C. I use 3M #77 spray adhesive to adhere the pattern to the top piece.
D. IMPORTANT - SAND all faces to at least 220 grit before even assembling the stack, backs are sanded to 150 grit.
E. Start with the most delicate areas first. If you screw up you waste boards but less time if something goes haywire.
F. When the cutting is complete, flip the stack face down on and totally flat surface and use the ROS with 150 grit to sand away as many of the 'fuzzies' as possible.
G. Carefully separate the stack, spray mineral spirits from a cleaning solution spray bottle and totally saturate the pattern, let sit for about 5 minutes and gently remove the pattern. IF you used packing tape over the pattern the 5 minutes will allow the mineral spirits time to soak under the tape for easy removal of the pattern and tape.
H. Gently wipe the face of the piece with a very soft cloth soaked in mineral spirits taking care NOT to SNAG any delicate areas. I use the blue paper shop towels available in most auto supply stores and W~M.
I. Allow the pieces to thoroughly dry, dip in a 50/50 mixture of Boiled Linseed Oil & mineral spirits. Wipe off excess and allow to dry for at least 24 hours checking to be sure that no 'mix' is weeping out of the wood (gently wipe it off).
J. Spray with several coats of Satin Lacquer (Minwax) sanding with a piece of brown grocery bag between coats.
K. Using Alene's Tacky Glue, attach piece to backer of choice, frame and display.
This is certainly not the only way to do portrait cuttings but is sure works for ol' GrayBeard....
~~~GB~~~