Ultra 100 Repair Tape?

Is the repair needed on the inside or outside of the bag?

Sorry. Outside.

I believe your best option is the Aquaseal +FD w/ accelerator, which is just the solvent to reduce it. Recommended to make a clean smooth and flexible repair. I’ve used on fully woven dyneema.

From web:  “ULTRA 100 uses a blend of 100den UHMWPE fibers and polyester for the outer fabric. Thanks to the very high proportion of 67% UHMWPE fibers, this achieves maximum abrasion resistance, tear strength and durability for the weight of 99g/sqm.”

Unfortunately, nothing much is going to stick effectively to the UHMWPE portion of the ULTRA, unless 1) the PE is surface-oxidized (e.g., corona treatment for printing on PE bags, and thermal oxidation of the PE melt web during high speed lamination to paperboard or Al film) or 2) the PE is taken into the melt phase for molecular entanglement.  Neither approach is practicable at home, though both approaches for bonding to PE have vast commercial importance.

Fortunately, various glues do stick to the polyester filament fraction.

Unfortunately (for adhesion), most of the fiber composition is UHMWPE, and thus poor bonding adhesion tends to dominate.

Thus, the solution suggested and TESTED by Simulacra resonates with me.  Use a glue that 1) sticks well to the PET filaments in the fibers and 2) likely MORE IMPORTANTLY is fluid enough to penetrate into the fibers and in amongst the fiber matrix .  This provides 1)  surface bonding to the minor fraction of PET filaments and 2) perhaps more importantly creates a penetrating mechanical interlocking that remains flexible once the glue sets up.

What my thought experiments perhaps add to the solution suggested and TESTED by Simulacra is that somehow “massaging” an initially more fluid glue into the fabric, rather than simply surface brushing with a thicker goo, is likely to be quite helpful for longer term results.

The non seam taped stitching holes to my pockets made from DCHW were like gutter downspouts in the rain. Applied Aquaseal FD to DCHW surface face at the start of last season. Fixed issue. Still bonded.

I know a few folks sell Ultra patches like SWD, but mostly for using the adhesive on the inside of the pack where it will stick.  If you want to use the patch on the outside you need use the aforementioned Aquaseal.

Looks like Aquaseal it is. Thanks everyone.