For some reason when I apply this glue to my senkos it just tears them apart. I guess that's the price of using them to catch fish lol super glue just hardens them and this stuff just splits the rips even further.

Might have something to do with the heavy salt content? Maybe the density? I don't know, I rarely use an actual Senko. 

Try applying the mend-it to the tear, and then holding it together for a while so that the glue has time to set.

Mend -It will do that to ANY plastic bait.  It's ment to react with the plastic and then reform.  It pretty much bonds them together by melting the plastic and then reforming.  If you're Senko is ripped, apply the Mend-It to the rip, then push it together and set it down.  I normally repair my baits after I get back home unless it's fishing a big swimbait.  I normally add a couple coats of Mend-It  repairing small areas at a time and then coating it after I have gotten most of the bad spots fixed.  

I use a Power Zap and must weld them with heat.

Well after holding them for a minute they did stick back together, just saved a few bucks so I'm happy

remember that Mend-it is not a glue but it causes a chemical reaction that fuses the plastisol together .

What i found works best for me is to throw the ripped ones in a pile when im on water. Then repair them when i get home with mend it. I also get a longer use out of repaired ones when i turn the lure 90* to how i hooked it before. Meaning if i ran the hook inline with the seam i turn a repaired one 90* to run it through seam instead.

I can tell ya it didn't work on powerbaits for me.