How To Repressurise an Aerosol Can
There are many different types of aerosol cans that have their own pressure-repressing requirements. The repressurising process is important because it prevents build-up of pressure. With an excess pressure, there is a risk that the can will burst and cause injury to the user. There are different methods for repressurising an aerosol can, and this article will highlight some of the most common techniques used.
Shake Repressurisation
This is the most basic form of repressurisation, but it is only suitable for low-pressure products like paints and adhesives. Here, the can is shaken vigorously until a foam or froth forms on the surface of the product. This means that the gas has been re-entrapped in the liquid, and the can is ready to be used again. This method is not good enough for most aerosols, but it can be useful for some low-pressure products. It is also easy to do, making it popular for people who have never repressurised a can before.
Headspace Repressurization
This technique works on the principle that the can has a headspace. This is the space between the level of the product and the top of the can. A gas-tight seal prevents any air from entering the can, preventing the pressure from rising. If the seal is broken, the pressure can cause the seal to rupture, and the product inside the can could be propelled out at high speeds. This could be very dangerous, even fatal, if it gets into the eyes. The headspace method involves repressurising the can by covering the nozzle with a finger or a thumb. This allows air to enter into the can, and it will mix with the propellant gas. When the two are combined they form a safe pressure that is less than what caused the seal to rupture. Once the can has been repressurised, it is ready to be used again.
Venting Repressurisation
This is also a type of headspace repressurisation, but it is used on canisters that have a removable cap or nozzle. The cap or nozzle is removed from the canister, and the nozzle is then covered with one of the methods listed above. Once repressurisation is complete, the cap or nozzle is replaced and the can is ready for use again. This is a useful method, especially for people who find it difficult to repressurise a can with their finger or thumb. It can also be used for canisters that do not have a removable nozzle.
Use A Repressor
A repressor is a device that uses a spring to retain pressure in the can. It is best used with high-pressure cans, but many repressors come with an adaptor that can be used with low-pressure cans. A repressor can be used to repressurise the can, or it can be used to depressurise the can. This is useful when repackaging the product into smaller cans or bottles. It is worth noting that repressors are not fail-safe. If the spring is broken or becomes faulty, there is risk of the can bursting. For this reason, repressors are not suitable for use with the low-pressure products that will be damaged by the pressure if the can bursts.
Conclusion
This article has highlighted some of the different methods used to repressurise an aerosol can. It is important to remember that these methods are only suitable for certain types of cans. Before attempting to repressurise any can, it is important to check the instructions on the canister. If in doubt, it is best to contact the manufacturer and ask for advice.
