Metal finishing Q&As since 1989

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Quality of Deionized water.

2000

As a craftsman I am setting up to do electroforming of copper to form coral-like nodular deposits. I was going to use DI water for rinsing and as a basis for the copper acid bath. I find that water deionizers can provide a range of water resistance from 50 kOhm-cm to 10 megOHM-cm.

I would like to know what is recommended for my particular application so I do not spend more money then I need to. Since I'm not striving to achive the smooth surface do I need to use the highest quality water? I hope to avoid extra expense by following someones advice based on their previous experiences and knowledge. Thanks in advance for your help.

Paul Stafford
gallery - Littleton, Colorado USA

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2000

A mixed bed filtration system will definitely give you the purity you need. You may be able to get away with just a cation/anion tank system. I have experience with DI water from running salt spray testing where the purity of water is specified by mega-ohm-cm. Contact a local water filtration company to get the equipment. You should find a listing in the yellow pages.

By the way, never let anyone drink DI water. Pure water is actually an aggressive solvent even though people might think, "Oh, it's just water." It won't immediately hurt you, but the pure water will actually leach minerals and nutrients from you. It's like the reverse of taking a vitamin.

Tim Neveau
Rochester Hills, Michigan

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Actually, if you drink a lot of DI water, you create enough osmotic pressure to rupture cell walls (or, at least, so says the Bundeswehr ABC und Selbschutze Schule in Sontofen, Ger). Not to mention the fact that it does not taste good!

James Totter, CEF
- Tallahassee, Florida
2000