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Aluminum Seals: A Quick Look At Hot DI Sealing

Most aluminum seals go through an anodizing process to reinforce and enhance their structural integrity and composition. Anodized aluminum seals are more durable, scratch and wear resistant and also have a better-looking finish that will keep longer. To close the porous layer of the aluminum oxide after the anodizing step, you will have to choose between one of many sealing processes. In particular, hot DI sealing is one of the most popular choices, and will be explored within this article.

The Basics of Hot DI Sealing

Hot DI sealing, also known as hot water sealing, involves immersing the anodized aluminum seal in boiling, hot, deionized water that reaches temperatures of approximately 205 to 212 degrees Fahrenheit. The hot, boiling water will cause a type of hydrated aluminum oxide, known as boehmite, to form within the pores, and deionized water will limit any chemical reactions that may happen during this process. By clogging up the pores on the surface, the anodized aluminum seals have a stronger structural integrity. 

Most experts recommend immersing the anodized aluminum seals for 2 to 3 minutes per micrometer of oxide coating. The amount of time is highly dependent on the temperature of the water with a higher temperature correlating to faster sealing times. To maintain a uniform temperature throughout the entire tank, a small amount of air agitation is used. The pH of the solution will also need to be adjusted with ammonia and other agents for an optimal seal. You can expect to see sealing smut form on the surface of the anodized aluminum. 

Benefits of Hot DI Sealing

In comparison to other sealing processes that can also be utilized for finishing off the aluminum seals, hot DI sealing offers many unique benefits that make it stand out from the crowd. Some of these benefits include:

  • faster sealing time. If you are processing large volumes of aluminum seals each day, you can expedite the processing times required and improve overall productivity by switching over to hot DI sealing instead, as the time that it takes for the process to be completed is rather minimal. You can decrease the sealing time by simply increasing the temperature of the water that the anodized aluminum seals are immersed in.
  • higher quality results. Hot DI sealing results in uniform thickness. In addition, the microstructures that form will strengthen the aluminum seals considerably, so that they can tolerate more wear, and are more durable.
  • enhanced dielectric strength. This is essential if the aluminum seals are going to be used in applications that require electrical conductivity. 
  • reduced chance of contamination. This can greatly improve the quality of the aluminum seals.
  • simplicity of the entire process. In addition, the entire process is relatively simple, and you will not have to hire specialized labor in order to get the job done. 

Considerations to Keep in Mind

Although there are many benefits associated with hot DI sealing, it is important to keep in mind that you will be using lot of energy to maintain the deionized water at a boiling temperature. The hot DI sealing process requires specialized equipment that requires a higher initial capital investment. 


Aluminum seals are used in many industries, as they are able to provide evidence of tampering, and are efficient and effective. They are able to prevent any leakages, and are able to offer a high level of protection and security. As a result, they are highly favored in many industries. The quality of the aluminum seals will be dependent on many factors, such as whether they have been anodized and the type of sealing process that the anodized seals have gone through. Hot DI sealing, in particular, generally guarantees high quality results. For more information on hot DI sealing, visit a site like