How to Break the Seal on a Caulk Gun (And Reseal It After)

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Home improvement & DIY specialist Emily Fazio shows us how to break open the inner seal of a caulk tube

Co-authored by Emily Fazio and Luke Smith, MFA

Last Updated: December 17, 2025 Fact Checked

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• Using Built-In Attachments
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• Using Household Items
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• Loading a Caulk Gun
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• Resealing Caulk Tubes
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• Video
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• Expert Q&A
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• Warnings

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Caulk is very useful for creating a protective seal around bathtubs, showers, and windows. However, if you have a new tube of caulk, there's a foil seal on the inside that has to be pierced before you can use it. Luckily, piercing this seal is a pretty straightforward process, even if you're a beginner! We talked to home improvement specialists and a handyman to show you how to quickly and easily open, load, and reseal a tube of caulk with nothing but household supplies.

Opening Caulk Tube Seals

Home improvement & DIY specialist Emily Fazio says it’s easy to puncture the seal of a caulk tube with a narrow drill bit or a 2-3 inch (5-7.6 cm) nail. Use a utility blade to cut the very tip off the nozzle at a 45-degree angle. Then, insert the drill bit or nail into the nozzle and push until the inner seal is broken.

Steps

Section 1 of 4:

Puncturing the Seal with Caulk Gun Attachments

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1. 
   1
   Place the nozzle’s tip in the hole on the gun's handle to cut it open. The hole is typically located on the left side of the caulk gun handle. Place the tip of the tube's nozzle in the hole at a 45-degree angle, then squeeze the gun's trigger quickly and firmly to slice open the tube. Note that the further down the tip that you cut it, the wider the hole will be.

   • So, if you only want to apply thin layers of caulk, cut open the tube near the tip of the nozzle. Conversely, to apply a lot of caulk at once, you cut the nozzle near the bottom.
   • Almost all caulk guns have this hole on the side of the handle. However, if yours doesn't, home improvement specialist Ryaan Tuttle says to use a sharp utility knife to cut open the tube. We’ll show you how in a step below.

   Meet the wikiHow Experts

   Emily Fazio is a home improvement & DIY specialist. She’s also the editorial director for HomeLivingHandbook, focusing on DIY projects, interior design, and home maintenance.

   Ryaan Tuttle is a home improvement specialist and the CEO of Best Handyman, Inc. in Boston, Massachusetts. With over 20 years of experience, he specializes in building home service businesses.

   Barry Zakar is a professional handyman and the founder of Little Red Truck Home Services based in the San Francisco Bay Area. With over ten years of experience, Barry specializes in a variety of carpentry projects.
2. 
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   Find the gun’s built-in seal punch and poke it through the nozzle’s tip. After the tip is cut, you still need to break the inner seal inside the caulk tube’s nozzle. To do this, use the seal punch, which is the thin metal rod on the tip of the gun's underside. The rod is on a swivel, so pull it out towards the side of the gun to deploy it. Then, holding both the seal punch and the caulk tube firmly, insert the seal punch into the tip of the nozzle and push them together until the inner seal breaks.

   • Pull out the seal punch and check it for caulk to confirm that the seal has been broken. Use a towel or cloth to wipe the caulk off the seal punch before you push it back under the caulk gun.
   • Most caulk guns come with this seal punch attached to them. However, if yours doesn't have a seal punch, use a nail, screwdriver, or a sturdy piece of wire to pierce the seal.
   • If the seal punch isn't located on the underside of the gun, it may be on the inside of the handle.
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Section 2 of 4:

Using Household Items to Pierce the Seal

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1. 
   1
   Cut the tip off the nozzle with a utility knife or scissors to open it. “We always use a very sharp utility blade or an OLFA knife,” says Tuttle. Hold the tube in your non-dominant hand while you cut it with your dominant hand at a 45-degree angle, then carefully slice the tip of the tube using a downward stroke, cutting away from you. Note that the further down the nozzle you cut, the wider the hole will be. The hole in the nozzle will determine the width of the caulk as it comes out of the tube, so cut the nozzle to the desired caulk width.

   • Or, use scissors to cut open the nozzle if you don't have a utility knife.
   • Most caulk gun nozzles have lines on the side that indicate the width the caulk will be if you cut the nozzle at that point. Refer to these lines when you're cutting to make sure you're opening the tube at the right spot.
   EXPERT TIP

   

   Barry Zakar

   Handyman

   Barry Zakar is a professional handyman and the founder of Little Red Truck Home Services based in the San Francisco Bay Area. With over ten years of experience, Barry specializes in a variety of carpentry projects. He is skilled at constructing decks, railings, fences, gates, and various pieces of furniture. Barry also holds his MBA from John F. Kennedy University.

   

   Barry Zakar
   Handyman

   You don't want too large a bead or too much caulk will come out. Better to go on the smaller beads rather than the larger side because then you just get too much.
2. 
   2
   Push a long, sturdy rod into the tube to puncture the inner seal. Fazio suggests using a narrow drill bit or a 2-3 inch (5-7.6 cm) nail. Push the drill bit or nail into the nozzle until you feel it reach the seal. Then, continue applying force to the nail to puncture the seal. “Just remember to wipe off any caulk that collects on the tip before it dries,” notes Fazio. If you don’t have a drill bit or nail, you might also use:

   • A long, skinny screwdriver
   • A thick, sturdy wire or wire coat hanger
   • A metal cooking skewer
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Section 3 of 4:

Loading a Caulk Gun

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1. 
   1
   Press the rear lever to release and pull back the plunger. Most caulk guns use a metal rod or plunger to push the caulk forward when you squeeze the trigger. To load the gun, first press on the metal or plastic lever keeping the rod in place, which is usually located at the back of the gun, behind the grip. Then, pull the metal plunger all the way back.
2. 
   2
   Position your caulk tube into the gun’s rack and push the plunger up. Now, place the tube of caulk into the holster or rack of the caulk gun so that the nozzle faces forward and the tube is snug. Then, push the plunger forward until it touches the caulk tube. Give the trigger a few short squeezes until you see caulk beading out of the nozzle. You’re ready to get caulking!
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Section 4 of 4:

Sealing a Used Caulk Tube for Later Use

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1. 
   1
   Place a snug nail or other plug into the nozzle’s hole. “The method that works best for us is to put a wide nail in the tip so that it’s nearly air-tight,” says Fazio. Alternatively, find a skewer, thick wire, or any other object that fits tightly into the nozzle of the caulk tube. Simply insert the object into the nozzle’s hole; the goal is to make it snug and nearly airtight so that the caulk doesn’t dry out.

   • It’s okay if it’s not a perfect fit, but try to make it as neat as possible.
2. 
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   Wrap the nozzle’s tip and plug with cellophane or duct tape. “I like to wrap a piece of cellophane around the tip and the nail head as an extra measure,” says Fazio. Or, use duct tape. Just wrap the cellophane or tape around the nozzle’s tip twice so that the plug is secured and the hole in the tube is covered and airtight. If you leave any large gaps, the caulk inside might dry out.

   • “Remember: the tube of open caulk won’t last forever,” explains Fazio, “but it’ll hold you over for a few days if you need time during your project.”
   • If it’s tight and resealed, you’ll be able to use the caulk up until its expiration date. Feel free to open and reseal it as many times as you like.
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Expert Q&A

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• Question

  How do you open a tube of caulking?

  

  Ryaan Tuttle
  Home Improvement Specialist

  Ryaan Tuttle is a Home Improvement Specialist and the CEO of Best Handyman, Inc. in Boston, Massachusetts. With over 17 years of experience, he specializes in building home service businesses, focusing on creating scalable and efficient brands. With the help of his global team, the companies have achieved over 10+ million in sales and received recognition through magazine features, and enjoy partnerships with wikiHow and Jobber field service software. Boston Magazine and LocalBest.com have named Best Handyman Boston the Best Handyman in Boston. Ryaan holds Construction Supervisor and Home Improvement Contractor Licenses.

  

  Ryaan Tuttle

  Home Improvement Specialist

  Expert Answer

  I always use a very sharp utility blade or an OLFA knife, which is also called a painter's knife. These are the sharpest options available.

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• Question

  How do you cut the top off of a silicone tube?

  

  Ryaan Tuttle
  Home Improvement Specialist

  Ryaan Tuttle is a Home Improvement Specialist and the CEO of Best Handyman, Inc. in Boston, Massachusetts. With over 17 years of experience, he specializes in building home service businesses, focusing on creating scalable and efficient brands. With the help of his global team, the companies have achieved over 10+ million in sales and received recognition through magazine features, and enjoy partnerships with wikiHow and Jobber field service software. Boston Magazine and LocalBest.com have named Best Handyman Boston the Best Handyman in Boston. Ryaan holds Construction Supervisor and Home Improvement Contractor Licenses.

  

  Ryaan Tuttle

  Home Improvement Specialist

  Expert Answer

  Just start in one of the corners with a sharp blade, and slowly get down to the bottom of it. You might have to do that a couple times, though.

  Thanks! We're glad this was helpful.
  Thank you for your feedback.
  If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow

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Warnings

• Be alert and careful when handling a utility knife; the blade is very sharp.
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