To me Studio by Sculpey Bake and Bond has been a godspend. I use it to permanently joinmy polymer clay designs to peper mache, wood, and metal objects. The best way to do this is: Do your design on the object. Flip the clay piece( the base if you are adding layers) then generously smear the bake and bond on the object. Let the smeared item rest for about 15 minutes or so. The bake and bond will self level. the flip the base back onto the object. Give is a little squiggle to set it and help remove any trapped air.
Once the base clay is set you can build up from there adding cane slices, dimensional pieces, transfers etc.
I haven't had any luck with recuring but it could have been the substrait I used(wood made in china) I have joined the polymer clay to the these objects with bake and bond.
Glad to answer any questions.