Caulk and seal a newly installed kitchen sink. Learn how, plus get expert tips on kitchen renovation and remodeling, in this free DIY home improvement video.  Once you have all the plumbing done and all the water connected up, you want to take some 100% latex silica caulking, and press it hard up against the edge of the sink. Let it get everywhere. Make sure you press it up against the sink really hard. Once you do that, you can either use your hand or a rag, and you’re just going to smooth it out more or less. It doesn’t have to be real clean, you can leave some on it.