Clean the area well with alcohol or paint thinner and let dry completely. Use a Kitchen/bath caulk---I prefer GE brand(at Home Depot).

There are some colored varities as well as some grout in a tube varities. The grout in a tube has to be sealed.

OK, will do. Maybe that's why it feathered because I didn't seal it. I'll look at the GE brand at HD. thank you very much.

To hold the backsplash firmly in place, I would recommend Polyseamseal All-Purpose Adhesive Caulk or Polyseamseal Tub & Tile Adhesive Caulk and avoid sealants with silicone even the ones that Polyseamseal offers.

Silicone is the most flexible but it has the poorest adhesion.

The backsplash (formica or something like that installed in the 70's) isn't loose. The seal broke and I pulled it out, now there's a gap. It was like a rubber seal. But anyway, I tried using the flexible caulk but that didn't work. I will look into your suggestions, thank you.

If the gap is deep, be sure to fill with backer rod first. I recommend anything BUT silicone caulk. The Dynaflex products and Polyseamseal work best.

Michael

Polyseamseal is not just one kind of sealant. There is a 100% silicone Polyseamseal, an acrylic one, an acrylic & silicone one, and a Polyvinyl Acetate one which is the original adhesive kind mentioned above (they include "Adhesive" in their names. The ones with added mildew resistance are labeled Tub and Tile. If silicone was used before you must remove all of it with a razor blade and abrasive cleaner or nothing will stick to the surfaces.