How to fix a cracked toilet, cistern or sink yourself

You can fix a cracked toilet, cistern or sink with cold weld for sanitary ware, a two-component epoxy putty for ceramics and faience. Clean the repair area, rough it up with coarse sandpaper, degrease and dry it, then press the kneaded putty into the crack; after 2.5 hours the joint can be sanded, loaded and painted. Shut off any leak under pressure first.

What you need

Epoxy putty for ceramics and faience, 55 g

Cold weld for ceramics and faience, 55 g

When you can repair a crack yourself

Cold weld for ceramics and faience repairs chips, cracks and missing fragments of toilets, cisterns, sinks, kitchen sinks, baths, shower trays and tiles, and seals joints in sanitary ware. The cured putty resists temperature changes and chemical reagents and withstands −60 °C to +150 °C. If the crack runs through the whole bowl or the mounting and the toilet wobbles, the repair is temporary and the toilet should be replaced. Do not glue a toilet to the floor with the putty: use its standard fixings.

How to fix a cracked toilet — step by step

1. Turn off the water and drain the area. Shut off the supply, empty the cistern and remove the water from the bowl or sink below the crack. The putty bonds even on a wet surface, but a leak under pressure washes it out before it cures.
2. Prepare the surface. Clean off dirt and deposits, rough up the edges of the crack with coarse sandpaper, degrease and dry. The strength of the repair depends on preparation.
3. Cut off and knead the putty. Cut at least 1/3 of the stick of NANOPROTECH Epoxy putty for ceramics and faience right across: in a smaller piece the ratio of components is off. Wearing gloves, knead it with your fingers, which you can wet, until the colour is uniform.
4. Fill the crack. Straight after mixing, while the putty is pliable, press it into the crack with a small margin over the edges. On a damp surface, keep smoothing it until it grips.
5. Bond a broken-off piece. Apply the putty to both surfaces, press them together and hold them for 15 minutes.
6. Smooth the seam. Shape it with a flat object moistened with water and remove the excess before the putty hardens.
7. Wait for it to cure and check the repair. After 2.5 hours the seam can be sanded, loaded and painted if needed. Then turn the water back on, fill the cistern and check for drips.

Why it may not work

• The putty came away. Usually the surface was not roughened or degreased: on oily surfaces the bond strength is 20% lower.
• The putty did not reach full strength. The piece was too small or unevenly mixed. Cut at least 1/3 of the stick right across and knead until the colour is uniform.
• The stick has hardened in the pack. This happens after storage or sharp temperature changes. Warm it to +60 °C for about 10 minutes, in hot water or on a radiator, and the putty becomes pliable again.
• The seam is a different colour. The putty is light-coloured but not pure white. To match the sanitary ware, sand and paint the seam after 2.5 hours.

Safety precautions

• Wear gloves and keep the putty out of your eyes. If it gets into them, rinse with water and seek medical advice.
• Do not apply the putty to surfaces that come into contact with food.
• Store the stick in a dry, dark place at no more than +35 °C, out of the reach of children. The shelf life is 18 months.

Frequently asked questions