Water and the Plating Process: Part 3

As we have discussed in part 1 and part 2 of this series, water is very important to the plating process. As an astute reader will recall, we are discussing how different types of water will affect the plating process. This week, we will wrap up the discussion with Purified Water.

Purified Water

Purified water, such as RO or DI water, will contain few to zero ions. Thus, it is very different from soft or hard water in how it relates to cleaner baths. Since there is a dearth of stuff in solution, purified water will not inhibit saponification. Purified water will also not increase the amount of sludge in the bottom of a cleaner. With purified water, you do not need to worry about some of the cleaner being used to soften the water, nor will you run into any extra issues with getting all of the cleaner into solution. Sounds like magical stuff, right? Well, purified water does have a down side, its cost. Relatively speaking, purified water is much more expensive than hard water, and is even more expensive than softened water.


The cost of purified water is its constant downfall. Were it as cheap as hard water, there would be absolutely no reason to use anything else. Because of this, purified water rinse tanks are not much more than a nice thought for many platers. Purified water is truly ideal in a rinse tank situation, since it will add next to zero to the process, and will readily accept soils/soaps from the surface of a part. There are ways to maximize rinsing with non-purified water, such as counter flowing the rinse tanks. As you might imagine, the effect of this practice would be amplified in a rinse containing purified water. Follow our blog to learn more about counter flowing rinses, and why you should be doing this if you haven’t yet. In the meantime, refer to last week’s blog post for more regarding rinsing.

As you have likely gathered thus far, purified water will cause little to no problems in the plating and post treatment tanks. You will not need to worry about sludge or outside contamination from your water source. You can be sure that whatever you put into the tank is the only thing present, and thus the only things that you need to monitor. In fact, I would make the argument that since your plating and post treatment tanks likely represent the biggest dollar value to you, that this is where the relatively high cost of RO or DI water may be worth paying. As they say, put good in, get good out.

To wrap things up nicely, there are three different types of water, and each affects plating in different ways. Hard water, while likely the cheapest water, has the potential to cause the most issues. Soft water, likely middle of the price range, in general does not have nearly as many problems as hard water. And finally, purified water, the most expensive of the bunch, should cause almost no issues in a plating line.

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