
Purple=1/2 in MDF
Blue= tip and tail sections made from 2x4's or MDF etc.
Green=camber spacers (more for longer boards)
this all gets hot glued together and sits on my work table.
One layer of 1/8 hdpe to smooth the transitions (once again hot glued.)
then the whole works gets vacuumed to the table pulling the ends down(arrows)
This has worked well for me. although the first skis I made ended up with a very strange camber due to not enough spacers underneath.
To see this in action see my log.
http://www.skibuilders.com/phpBB2/viewtopic.php?t=1407
(sorry about my drawing skillz

hope this helps
sam