Bonding Hybrid DCF

You could try 3M 9485 transfer tape. It is an near to permanent as I have ever seen. (Does NOT work on silnylon or silicone DWR though.) You can buy it on eBay.

Cheers

Thanks for the tip. The only thing I found was some double sided tape from Ripstopbyyheroll.com.

Just to to be clear, only one side of the DCF hybrid is tapable.

Only one side?  The DCF Side?  I cant bond the DCF Side to the Nylon facing successfully with tape?  Would SeamGrip do the trick?  The part I am trying to seal is on my HMG Southwest, I am trying to seal the second bottom layer of DCF that the pockets were sewn to.  I have removed the 2 side pockets, contemplating the center pocket removal.  This leaves a two inch “Gutter” on the bottom of the pack that I was hoping to secure/seal up.

Conventional adhesives will not bond to any silicone surface, and usually bond poorly to any DWR-treated surface.
Heat-bonded PU tape has the same limits.
Silicone surfaces and seams can be handled very well with silicone sealant.

Cheers

Yes the nylon side is as usual as any “common” fabric so it can’t be sealed. If you mean to add waterproof to the pack, I think all the stitches on a HMG pack is covered with a cuben tape to resist water from the inside of the pack (the DCF side of the hybrid cuben).

The only exception is the pack’s bottom circle of stitches that are not flat and covered with a non-DCF strip. Water may come in from the bottom seal of the outside pockets, but will go between the layers, since the pack’s bottom has two layers of DCF?