I became disgusted with the effectiveness and durability of silicone calk decades ago. It's "OK" for a limited number of jobs.
My suggestion is to try out repair sealants before committing to use them.
On things that flex like plastics, vinyl, rubber, I found that 400 sandpaper "scuffing" and applying GOOP brand sealant (all Goop sealants are the same regardless what the tube label "says") is so superior to anything else it is almost criminal to use anything else. It sticks where nothing else will stick and furthermore it stretches like a rubber band then snaps back.
I repair shoes with the stuff. Down here in a pinch (Size 13 is harder to find than an honest politician) I have glued snapped sandal straps, even flapping soles, and despite horrendous abuse the glued parts stay tightly glued and few things need as much flexibility as sandals and shoes. The stuff can be painted over. Although flexible paint isn't easy to come by. Goop is transparent.
Again, ignore what the label says: Plumbing, household, marine, auto, it's all the same stuff. Lately E2000 brand adhesive has appeared. I found it to be exactly the same adhesive. Home Depot, carries these adhesives. Around $5.00 per tube. The adhesive has a finite life after opening after which it becomes rubber-like inside the tube.
