Leak-detection soap is useful for detecting leaks in pressurised lines or pipes, such as gas lines, water lines (PVC or copper), fuel lines, and even tyres. Leak detection is necessary any time new pipes or lines are run or replaced to make sure the pressurised material -- whether it is water, liquids, gas, oil, or air -- will not leak at joints or breaks. A basic soap solution is sprayed or applied to the lines at joints or areas that show a potential leak, then watched for signs of soap bubbles indicating a leak that needs repair.
Open a 9 litres (2 gallon) sprayer and add 4.5 litres (1 gallon) of water into the reservoir. Measure at least 57 ml (2 oz) of washing up liquid and add it to the water.
Measure 57 g (2 oz) of glycerine in a measuring cup and add it to to the solution in the sprayer, then mix the solution with a stick.
Pour some of the mixed soap solution into a plastic tray and set it aside. Replace the cap on the reservoir, then give the sprayer a few pumps to prime it with the soap solution.
Spray the soapy solution on the areas of the line or pipe that require leak detection, or use a paint brush to apply the soap solution from the tray.
If you need more soapiness or a thicker solution, add up to 284 g (10 oz) of washing up liquid. Adding corn syrup or glycerine to the leak detection soap lowers the rate of evaporation so the bubbles last longer at higher temperatures -- over 26.7 degrees Celsius (80 degrees Fahrenheit), and increases the solution's viscosity so it will drip less when applied. Substitute a -32 degrees C (-25 degrees F) or more windshield-washer solution for water in the soap solution for use in freezing temperatures.
Some industries require specialised, commercially-made leak detection solutions in order to meet legal leak detection requirements.