How do you stop a sealant gun leaving a blob at the end?

What happens when you squeeze?

• An even bead comes out. Now practise stopping: let go of the trigger, release the pressure and lift the nozzle away.
• The bead widens as you reach the corner. Watch the hand guiding the nozzle. If it stops while your trigger hand keeps squeezing, the sealant builds up there.
• The trigger feels unusually stiff and nothing comes out, or sealant comes out at the back. Stop squeezing. Release the pressure before checking the outlet and cartridge.

When preparing a fresh cartridge, use the Stanley knife as instructed. Cut the nozzle away from your fingers. This cartridge tool is not a scraper for glass, fabric or a shower tray.

From loading the cartridge to stopping the bead

1. Check that the cartridge fits your gun. Retract the rod using the release on your model and open the cartridge outlet as directed on the pack.
2. Fit the nozzle and start with a small opening. Cut away from your fingers. If the hole is already too large, use a fresh nozzle.
3. Set the pressure plate squarely against the plunger. Run two lines on cardboard with the same nozzle, one faster than the other. Compare where each line starts and stops.
4. Follow the joint with the unloaded movement first. Find a comfortable hand position before you reach the corner. When applying sealant, move steadily and release the pressure as you finish the run.

Dry-fit the FUGENFUX profiling tool. Choose the edge that meets both sides without scooping out the middle, then tool the bead before a skin forms.

What the cardboard test tells you

Cardboard helps you control the flow. It cannot tell you whether the sealant will stick to your tiles or timber. If paint flakes off the edge or the joint is still wet, prepare the surfaces first. A thicker bead cannot hold a loose edge in place.

With a manual cartridge gun, practise a few short runs. Release the pressure at each stop and watch how much material stays on the nozzle before starting the next line.