Caulking Questions

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Every painter has to caulk. Here are common questions that come up, along with some easy solutions.

Q: When is quick-dry painter’s caulk OK?

A: Use quick-dry painter’s caulk in areas that won’t move a whole lot. Those types of caulk are great at doing what they say: drying quickly. But in order to achieve that, they’re full of fillers that severely reduce elasticity. If they are used on fresh crown molding, you’ll have a lot of cracking caulk to fix. Use as a quick fix for a drywall crack, and you’re good to go.

Q: So if I can’t use a quick-dry caulk on fresh crown molding or other high-movement areas, what do I use instead?

A: Use an elastomeric latex caulk formulated specifically to stretch a lot. These products usually require more cure time before painting (generally 12-24 hours), but they won’t crack, which translates into fewer call-backs, which means saving money.

Q: The caulk has split down the middle. How do I fix it quickly?

A: Use a custom-colored caulk. So long as you used a latex caulk that is free of silicone, cut it to relieve the pressure and re-apply a custom-colored caulk (Sashco’s eXact color and Red Devil’s Create-a-Color are two commonly available brands.) You simply mix in the paint with the caulk base to create a perfectly matching caulk. That allows you to cut out a step: no painting after fixing the caulk line! These products are generally more expensive, but the time and labor savings cancel out that higher cost.

Q: Why is the paint cracking over the caulk, and how do I prevent that?

A: Most likely, the caulk you’re using is elastic and your paint is not (at least not as much as the caulk). If the caulk moves more than the paint can handle, the paint will crack over it. That is more likely to happen on high-stress joints and with flat paints, which are usually full of fillers to bring out that flat look, decreasing their elasticity. The solution: Use a custom-colored caulk after all painting is done, or allow the caulk to cure longer before painting over it.

Q: Prime – caulk – paint, caulk – prime – paint or prime – paint – caulk…so many choices. Which is best?

A: If you plan on painting the caulk, the best sequence is prime – caulk – paint. The primer is good not only for paint adhesion, but also for caulk adhesion. If you are using a custom-colored caulk, the sequence will be prime – paint – caulk. In all cases, the assumption is that you are using products that are compatible. (See the next question about compatibility.)

Q: Compatibility? What the heck is that?

A: Compatibility is important! Put simply, compatibility means using caulk that will stick to your paint/stain and vice versa. It seems like a silly thing to mention, but problems associated with incompatibility are commonplace. Many paints these days contain silicone additives to help improve water resistance and/or durability, and many (but not all) oil-based stains contain waxes. Caulk won’t stick to either silicone or waxes, and you’ll just be frustrated with the constant caulking failures. Make sure your products will stick to each other and you’ll save yourself some frustration (not to mention time and money). Call the manufacturer of either product. They’ll usually know what works best with their products.

Q: The manufacturer suggests using silicone, but everyone knows pure silicone is not paintable. What do I use instead?

A: Silicone is recommended for use around many fixtures where there will be water and those fixtures must be somehow caulked. Instead of silicone, look for a clear co-polymer rubber product. These can be painted, or they can simply be applied after painting. Many are ultra-clear, which means the paint shows through.

Q: My fingers hurt after smoothing out (aka tooling) so much caulk. What else can I use?

A: Tooling caulk can be tough on fingers. Here are some other methods to consider:

1) Use a beading tool.

2) Use damp foam paint brushes or sponges.

3) Trowels always come in handy.

4) There are some who keep latex gloves around and just use a little water on the tips of gloved hands.

Old habits die hard, so you can always stick with the tried and true. But if you use a new way, you may find that some of these other methods are faster (which can save you both money and prevent sore fingers over time). APC


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