Tips For Caulking

Apply painter's tape to control your caulk lines. Apply the caulk, smooth the joint with your finger and immediately remove the tape.

The selection in the caulk aisle at home centers is mind-boggling, but actually choosing the right one is pretty simple. Most of the caulk on store shelves is basically one of four types: elastomeric, polyurethane, latex or silicone. Here's how to make the right choice:

• Siding, windows and doors: Polyurethane is best. It's paintable. It doesn't shrink. It stays flexible. It adheres better than silicone, and it doesn't attract dust and dirt the way silicone does.
• Roofing: Use an elastomeric or rubberized product. This stuff won't dry out in extreme conditions, and it sticks to everything.
• Interior trim: Use latex if you're sealing gaps and nail holes in trim that's going to be painted. It cleans up easily and dries fast. It's also easy to tool—and cheap.
• Kitchen and bath: This is where silicone products shine. Silicone tools well. It can be purchased with antimicrobial additives, and can be easily removed and replaced when it gets grungy.

The most expensive gun on the rack isn't necessarily the best. Look for a gun with a cradle. Tubes seem to fall out of the guns with the rails. Choose guns with ratchet action rather than friction action and don't consider a gun that doesn't have a hook. Forget about gun-mounted tube cutters—use a utility knife. And if all other things are equal, buy the gun with the longer tube poker. Some aren't long enough to work on every kind of tube.

You probably learned to cut the tip at an angle. That works OK in some situations, but an angled tip limits the position the caulking gun has to be in. With a straight tip, you can swivel the gun out of the way of obstacles and caulk right up to an inside corner. And if you have various-size gaps to fill, cut the tip small and do the small gaps first, then cut it bigger for the larger gaps.

The new guy left the case of caulking out in the rain again (it's always the new guy). Those soggy tubes are now going to split open under pressure. Before that happens, wrap some duct tape around the tube. You can also salvage tubes with house wrap tape, masking tape, stretch wrap, shipping tape—it all works. Just use whatever's handy.

When you have a long bead to run and you can't get it done in one shot, don't start again where you left off. Instead, start at the other end and meet in the middle. It's hard to continue a bead once you've stopped without creating a glob. Also try to keep the meeting place somewhere other than eye level.

It seems you can never seal the cut tip of a partial tube well enough. A plug usually forms in the tip. Try using a large screw with aggressive threads to remove the plug. This tip works best with silicone products.

A common mistake is to cut off too much of the caulk tube tip, leaving a hole that's way too big for most interior caulking work. When you're filling small cracks to prepare for painting, cut the tip carefully to keep the hole tiny—about 1/16 in. in diameter. The tiny hole lets out just enough caulk to fill typical small- to medium-size cracks. For larger cracks, make a second pass or keep a second caulk gun on hand, loaded with a tube that has a slightly bigger hole. Keep the caulk gun moving quickly along the crack as you squeeze the trigger. This, combined with the small opening in the tip, will give you a nice caulk joint that needs very little cleanup. A quick swipe with a dampened fingertip will leave a paint-ready joint.

If you're caulking concrete, either to fill a crack or to seal it around the edge, you can make the caulk almost invisible. Simply dust the caulk with dry concrete mix while it's still wet. When it's dry, brush away the excess, and the caulk will virtually disappear.

When you need to caulk in a spot that's too tight for a caulk gun, try this: Cut a sharp angle on the end of a plastic straw, just as you'd cut the spout of a caulk tube. Then fill the straw with caulk using a caulk gun. Fold over one end of the straw and squeeze caulk out the other end. You can lay a bead of caulk in cramped quarters this way, but it's hard to squeeze out a consistent, even bead. So keep a damp rag handy and plan to smooth the bead with your finger.

Every tube of caulk contains its own spout sealer. Force enough caulk out of the tube to form a peanut-sized ball. Then wet your finger and shape the ball to form a cap. The cap will slowly harden and keep the caulk inside soft for weeks.