Applying sealants

Sealants (apart from brushable types) are applied using a caulking gun, which can take a little practice to use properly. Before putting the cartridge into the gun, the tip tube may need to be cut off to allow the sealant to be forced into the nozzle. Once this is done, screw the nozzle back onto the tube then clip off the end of the nozzle at a 45-degree angle, using a sharp utility knife. The further down the nozzle you cut it, the larger the bead of silicone that will come out. If you only need a very fine bead, clip it off quite close to the tip as it’s

always easy to make the bead larger if required.

Slide the handle of the caulking gun all the way back, then slip the tube into place before pushing the handle of the gun in until it stops against the plug in the end of the tube.

To apply the silicone, turn the handle and then firmly apply constant pressure to the trigger until the silicone starts to flow out the end of the nozzle. To stop the flow, turn the handle until the pressure is released.

There are two ways of applying silicone – either ‘pushing’ the bead in front of the nozzle or ‘pulling’ it behind the nozzle. Try and produce an unbroken bead of silicone but, if necessary, smooth it out with a filling knife.

To create a tidy job, apply masking tape to both surfaces, creating a ‘valley’ where the silicone can be applied. As soon as the silicone has been applied, remove the masking tape. Alternatively, spraying the area with a fine mist of soapy water allows any excess sealant to be cleaned up effortlessly.