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Caulking: Lay a Better Bead

Caulk/Sealant Products, Home Improvement Products, Repairs, Trim Carpentry January 24, 2013 Sonia



 

 

 

 

 

Caulking: It’s a necessary evil. Applying the stuff is a messy job, often requires uncomfortable work on your knees, and it’s just terribly unexciting. But when it comes to Sealing out water and other elements, skipping the caulk will guarantee even more work in the future when you’re forced to repair rot damage. And from an aesthetic standpoint, caulk gives any paint job or trim project—inside or outside the home—the sought-after finished look that separates professional-grade jobs from amateur attempts.

Product selection is critical, from silicone to acrylic to water-based formulations. Check the packaging for specific indications, paying attention to words like “paintable” and “flexible”. Kitchen and bath caulks usually include a mildewcide.

The Right Stuff

Product selection is the logical place to begin the job, and silicone-based sealants have long been the staple for exterior projects where a waterproof seal is necessary. However, standard silicone cannot be painted and is incredibly messy and sticky to use. Acrylic caulk is only appropriate for interior projects and is not waterproof, nor is it very flexible and may crack over time. However, acrylic caulk can easily be painted and is much easier to tool and clean up than silicone. Standard acrylic caulk is primarily decorative and not intended to serve as a sealant.

Some hybrid products serve as caulk, sealant and adhesive. King Kaulk is a hybrid polymer sealant that permanently bonds to wood, concrete, brick, metals and plastics like strong glue.

These days, many caulk/sealant products come in hybrid formulations containing some of the attributes of both silicone and acrylic, meaning they can be cleaned or tooled more easily, remain flexible, can be painted and still retain a waterproof seal. Complicating the selection further is the advent of high-end water-based caulk/sealants that have similar hybrid properties.

Some caulk/sealants are formulated for special application. Sashco’s Slab concrete crack repair caulk combines superior adhesion and elasticity for extra durability. The product’s waterbased formula is easy to apply and clean up.

The easiest way to parse the options is to pay close attention to the indications on the packaging, making sure they match the job at hand. For example, Kitchen and Bath sealants will usually include a chemical mildewcide in the formulation for better performance in those moist environments. If choosing an exterior caulk that needs to be painted, then make sure your product indicates that the product is paintable, because you won’t be able to paint standard silicone—no matter how many coats you throw at it.

 

The Right Technique

Before applying any caulk or sealant, clean the surface of the work area thoroughly. This commonly overlooked step will prevent grit and debris from disrupting the application of the bead and keep unsightly dirt and dust from becoming embedded in your fresh caulk.

Clean the work area thoroughly to keep the caulk clean and ensure the best adhesion.

Cut the tip of the tube at a straight 90-degree angle. Start at the tip to keep the hole small. You can always recut to make the hole bigger, but you don’t want it too big or you sacrifice control of the bead.

Rest the nozzle tip evenly on both sides of the joint.

Many caulks/sealants have an interior seal that should be punctured inside the nozzle with a stiff wire or thin rod. Puncture this seal several times to make sure it is broken and the caulk will flow without restriction when the caulk-gun trigger is pulled.

Professional craftsmen rarely mask off a caulk bead with painter’s tape, but that doesn’t mean that you shouldn’t. Masking the joint is an easy way to eliminate mess if you’re not comfortable with your application prowess.

With the caulk tube loaded, pull the trigger several times to advance the caulk to the tip of the nozzle. Release pressure from the plunger or driver arm any time you’re not applying caulk to prevent excess from squirting out of the gun. Some caulk guns are indicated as “drip-free,” and prevent the caulk from flowing when the trigger is released.

Begin application at the horizontal joints. To ensure a full bead that adheres to both planes of the caulk joint, rest the tip of the nozzle equally on both surfaces. Depress the trigger with one hand to force caulk into the joint as you stabilize the gun and move the bead with the other.

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Keep the gun positioned at a 90-degree angle to the wall as you move the gun to lay the caulk bead. The right-angle position strikes a balance between pushing and pulling the bead for consistent application and easy visibility on both sides of the nozzle. Move the caulk gun at a steady rate, keeping the bead width as steady as possible and making sure to leave no gaps in the bead. If you cross any vertical joints, take the time to caulk a few inches up or down the joints, which will make it easier to connect the caulk beads later.

A sprayable release agent can make it easier to tool the caulk joint.

The Right Shape

One new option for tooling a caulk bead comes in the form of sprayable release agents. With these products, spray the completed caulk joint holding the can or bottle 4 to 6 inches away. The release agents prevent the caulk from sticking to the areas you spray and make shaping the joint much easier.

Tooling the bead sets the caulk into the joint and removes excess product.

A traditional caulk shaping tool is a short wooden dowel (or a variety of dowels of different sizes to create beads of varying sizes). Wet the dowel and draw the end of it over the caulk bead to scrape away excess product and press the bead into a concave shape. Keep plenty of paper towels (both wet and dry) on hand for the inevitable cleanup. Another option is to use a wet finger to shape the bead, but this obviously creates a mess, especially if you coat your fingers in the tar-like stickiness of silicone.

A number of caulk-shaping tools are available at most hardware stores.

I prefer to use the new rubber shaping tools available at most homes stores. Rubber caulking tools, such as the Pro Caulk kit from Dap, have a large enough working surface to clean away most of the excess caulk while offering a variety of bead shapes, including multiple concave beads, 45-deg. bevel shapes and 90-deg. beads for filling gaps.

Finish the caulking job by filling all the vertical joints, tying them into your horizontal runs.

“Control” and “consistency” are the keys to a better caulk bead. Practice these techniques the next time you’re saddled with a caulking project and you may just fine that you hate the chore a little less.

Side Note 1

Color-Matched Caulking

ExactColor Sealant is an easy way to create your own custom color sealant, and no special tools are required. Each tube comes complete with everything you need to tint the caulk, including a plastic syringe and chemical activator. The color comes from standard latex paint, water-based solid stain or universal pigments—using any color you prefer. Simply fill the syringe with 30 ml of paint or pigment and inject it into the tube of caulk. Shake the tube for 60 seconds. Then, add the tube of chemical activator and shake again to thicken the liquid into caulk. The ExactColor is then ready for application, extruding from the caulk gun as a smooth, workable sealant. Create a perfect color match to your project or highlight an architectural feature with a contrasting color caulk. This water-based acrylic sealant offers powerful adhesion, is easy to clean up and features elastic flexibility to prevent cracking.

 

Side Note 2

Crucial Features for a Caulk Gun

Caulk guns are relatively inexpensive tools, so it makes sense to pay just a little extra for a gun with three key features.

First, look for a gun with an integrated spout cutter typically located in the handle. Every tube of caulk will need to have its spout clipped, and there’s no reason to lug around an extra pair of snips when you have this feature.

Second, choose a gun with a flip-out seal punch. This super-simple feature should come on every gun, but it doesn’t. It’s a small metal rod that punctures the interior seal, so you don’t have to monkey around with a wire coat-hanger or other makeshift implement.

Third, the EHT staff prefers a caulk gun with a geared drive mechanism with visible teeth on the driver arm. The less expensive variety relies on a friction lever that can wear out and slip over time, creating gaps in the caulk bead. The superior geared variety has a more positive interface for better grip to the driver. Professional tradesmen who do a lot of caulking might consider a battery-powered caulk gun that can apply a consistent bead at the single press of an electric button.