When >using caulk, whether its silicone caulk or acrylic caulk, your goal is to create a quality seal. To do this, you need to know what material to use, how to prepare the gap you need to fill, and how to lay down a fine caulk bead.
There are two basic kinds of caulk available to builders today: acrylic caulk and silicone caulk or solvent based caulk. Acrylic caulks adhere well to wood and porous surfaces and are great for filling gaps that need to be painted. Acrylic caulks clean up with water, but also break down faster when exposed to standing water.
Silicone caulk, or solvent based caulks, will shrink less over time and deteriorate slower when exposed to water. They are a bit harder to clean up, but they work well in the kitchen and bath where water is more common. Silicone caulks don't take paint well, so they should be applied as a "top coat" or as an exposed surface.
After you've picked the right caulk for the task, it's time to inspect the seam or gap and prep it for a beading. Never try to caulk a gap larger than 1/4". If the gap is wider than that, install a backer rod first. The backer rod allows you to use less caulk and lay down a more consistent bead. Make sure the area you are about to caulk is clean, as a dirty surface will keep the caulk from adhering properly.
How to do it:
1. Cut the nozzle of the tube at a 45-degree angle about a half an inch from the end. You want to make a hole about the same size as the gap you need to fill.
2. When applying caulk to a seam, move the tube at a 45-degree angle, slowly pulling the tube towards you. You want to make sure that the bead is even and completely fills the seam.
3. When finished, smooth the seam using a caulk smoother, a clean wet finger or a clean damp rag. Be sure to allow the caulk to dry adequately before painting over it.
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