Homebrew PCBs

As a side note, powered hot-melt adhesive would be hard to apply 
evenly.  If you only wanted to do bonding (without needing the 
conductive additive) I would suggest using photo-mount paper available 
from camera/photo supply stores.  This is a very thin (probably about 1 
or 2 milli-inches) sheet of hot-melt on a carrier release paper and 
especially good on paper and archival mounting of photos in scrapbooks, 
etc.

Another technique for conductive traces was to add graphite powder to 
epoxy.  Totally load the harder with graphite to form a paste then add 
the other part (the resin) and use immediately.  Adding the graphite to 
the resin was not recommended as it could case the resin to harden.   As 
a thought, use a two-part urethane and add the graphite to it, and 
screen print it.  This is essentially what some some of the flexible LCD 
flex connectors are, screen printed conductive graphite ink on plastic 
(polyester or Kapton).  You could also use a solvent based carrier 
vehicle if you wanted to -- the key would be to really load it up with 
graphite.

Regards,
Charles Patton