How to Use a Caulk Gun

Clean up the space

If you’re dealing with moldy, old or deteriorating caulk, do some cleanup before administering new caulk.

• Use a utility knife, putty knife or a caulk removal tool to scrap off the old caulking.
• Once the surface is clear, clean it with some rubbing alcohol.
• Let the surface dry completely. If any moisture remains, mold could form under the new caulk.

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How to open a tube of caulk

• Some caulk guns come with a spout cutter built in. If not, use a utility knife to cut the tip off the caulking tube at a 45-degree angle.
• For fatter lines, cut the nozzle closer to the tube.
• Use the thin metal rod attached to the underside of the caulk gun to pierce the inner seal. If your caulk gun doesn’t have a seal puncher, a nail works just as well.

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Prep the surface

• If indoors, use painter’s tape above and below where the caulk will go to create a clean line and give you a target.

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Caulk gun loading

• Typically, smooth rod caulk guns feature a metal trigger on the back. While pressing it down, pull the L shaped rod back as far as you can.
• Insert the tube by pressing the flat base of the tube to the back of the gun, then placing the nozzle into the hole at the face of the gun.
• Pull the trigger until the base plate of the rod is firmly against tube.

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Using a caulk gun

• Practice using the caulk gun on a piece of cardboard.
• Squeeze the trigger and move down the line at a 45-degree angle at a consistent pace. If you go too slowly, the caulk might end up clumping. Too fast, areas might not get covered.
• If the line is too small, cut the tube again to make it bigger.

Taking this approach will greatly minimize the chances of a caulking mistake. Once you have the hang of it, go ahead and start caulking!
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Finishing step

• For a perfect line of caulk, dip your finger in water, then run it over the caulk.
• This will also push the caulk into the joint, making a tight, smooth seal.
• Wipe the excess caulk off your finger with a wet rag.

Pro tip: Start running the finger ahead of the caulk a bit, then keep going. This will keep the line smooth from start to finish.

If the caulk ever becomes too thick at one point, run a wet finger through the line to remove it. Don’t leave an edge behind, because it will show up if you paint over it.
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Let it dry

• Remove the painter’s tape.
• Let it dry, per the instructions on the caulking tube.
• Once dry, you can paint over it. Or, in the case of a tub, take that long soak you’ve been dreaming about.

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