Caulking gun: common mistakes and how to avoid them

Learn to load, cut, and control a caulking gun so you lay one smooth, even bead of sealant, not a mess.

CG-01Load the cartridge correctlyA caulking gun is a metal frame with a trigger and a long metal rod (the plunger) that pushes the back of a sealant cartridge. Open the frame, drop the cartridge in nozzle-end first, then close it so the plunger sits flat against the cartridge's back plate. The mistake beginners make is loading it backwards or at an angle, so the plunger skids off the plate instead of pushing straight.

1 each · Sealant cartridge (e.g. silicone)

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CG-02Cut the nozzle at an angleThe nozzle is the plastic cone on the cartridge. Using a sharp knife, cut across it at about 45 degrees, close to the tip. The size of the hole controls how thick your bead of sealant will be, so cut small first - you can always cut more off, but you can't uncut it. Beginners routinely cut too much off the tip and end up with a bead far wider than the gap they're filling.

CG-03Puncture the inner sealInside the nozzle there's a foil seal you can't see once the cartridge is loaded. Most guns have a thin metal pin built into the frame for this - push it up through the nozzle to break the seal. If your gun doesn't have one, use a long thin nail or skewer. Skip this step and nothing comes out no matter how hard you squeeze the trigger.

CG-04Prepare the joint before you startWipe the gap clean and make sure it's dry - sealant won't stick properly to dust, grease, or old flaking sealant. Run two strips of masking tape along either side of the joint, leaving just the gap exposed, so any wobble in your hand lands on tape, not on the tile or bath.

1 roll · Masking tape

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CG-05Pull the gun, don't push itHold the gun at a steady 45-degree angle and pull it towards you along the joint in one smooth, continuous motion, squeezing the trigger at an even pace. Pulling gives you a clean, controlled bead; pushing the gun away from you tends to pile sealant up unevenly and trap air underneath. Beginners often stop and start halfway along, which leaves a lumpy join where the two beads meet.

CG-06Release the pressure every time you stopMost guns have a small release lever or thumb catch near the trigger. Every time you pause, press it to relieve the pressure on the plunger rod. If you don't, sealant keeps oozing out of the nozzle for several seconds after you've stopped squeezing - beginners call this 'the drip you didn't ask for' and it's the single most common caulking gun mistake.

CG-07Smooth the bead while it's still wetDip a finger (or a proper caulking tool) in water with a little washing-up liquid, then run it along the bead once in a single, gentle stroke to press it into the gap and leave a slightly concave, neat finish. Wipe excess off your finger onto a cloth as you go rather than back onto the sealant. Peel the masking tape off straight away, before the sealant skins over, or it'll tear the edge as it comes off.

1 squirt · Washing-up liquid

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CG-08Check you've got it rightA good bead is one continuous, even width from start to finish, sits slightly concave (curved inward, not domed up), and has no gaps, air bubbles, or ridges where you stopped and started. Run your finger lightly along it once dry - it should feel smooth, not lumpy or stringy. If you see uneven patches, it usually means inconsistent pulling speed or forgetting to release the trigger pressure - both fixable next time.

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