Originally Posted by
rootboy
Contact cement. Either Barges or Weldwood, etc. The trick is having an "anvil" with which to stick inside the shoe, so you can tap the piece-O-leather down all the way around the edges. Short of that, stuff paper towels in the shoe as tight as you can get it, or cedar shoe trees may work, and then wrap the shoe with strong tape, pulling the edges of the new sole tight. Problem with this approach is that the tape may affect the finish on the leather. Masking tape shouldn't.
Having a shoe anvil really helps though as you can hammer the leather down to the cemented surface. Then trim around the perimeter to the final shape.
RB, to help the OP and me, please clarify: For contact cement bonds is the technique impact sealing ("tap the piece-o-leather down") or constant pressure as with using clamps to bond woodwork ('wrap the shoe with strong tape'). I've often wondered about the nature of bonding contact cement - like using Weldwood or spray adhesive on things or bonding tube patches to inner tubes.
BTW: I assume you mean the old school toxic medieval Weldwood contact cement vs the new water based Weldwood. The new water based stuff is a really poor product. Even Weldwood admits the stuff is 'finicky".
Quick solid impacts or firm long duration clamping pressure?