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Has anyone added salts BACK into DI water to make it suitable for stainless steel?

I need to house water in a stainless steel pan. We have a milli-q system in house, but it goes straight from tap to type 1, forcing me to buy large quantities of distilled water from a vendor. Has anyone ever added salt back into DI water to make it more like distilled?

Thanks

Jesse Columbo
student - San Diego, California
2007

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First of three simultaneous responses --

Your question is somewhat confusing. Distilled water is the purest water available. It should not have any salts in it. DI water is a chemical ion exchange treatment that mimics distilled water for a lower cost. What is the conductivity of you DI water and your distilled water? If you are having problems with SS corrosion you might not be rinsing you DI system well enough after a regeneration cycle.

Kurt Sammons
- Inman, South Carolina
2007

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Second of three simultaneous responses -- 2007

Not to my knowledge. Maybe deliberate misinformation from the distilled water vendor?

ASTM D1193 Type I water (18 Meg-Ù) is better for stainless due to its very low chloride limit, 1 microgram/Liter (chloride attacks stainless steel surfaces). Is the distilled water Type II, III or IV? These have chloride maximums of 5, 10 and 50 micrograms/Liter, respectively.
The only advantage of distilled water is sterility, for which Type I water may require heating.

Is the storage pan covered and purged with nitrogen? In addition to ASTM D1193, I suggest reading ASTM D4453, 'Standard Practice for Handling of Ultra-Pure Water Samples.'

Ken Vlach [deceased]
- Goleta, California
Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.

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Third of three simultaneous responses --

There is no salt in distilled water. There is nothing but water in distilled water.

Perhaps you can explain more clearly what you want to finish up with and why, because your original post doesn't really make much sense to me :-)

Bill Reynolds [deceased]
consultant metallurgist - Ballarat, Victoria, Australia
We sadly relate the news that Bill passed away on Jan. 29, 2010.
2007

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The comments above are correct - distilled water does not have any salts dissolved in it. I am not conversant with the Type I, II, III and IV waters mentioned above, but what I do know is that chloride dissolved in water will attack stainless steel and cause pitting. I would even go as far to say, it is one of the more common ions that should be avoided the most if you want to avoid metal corrosion. It will also attack aluminium and even help cause corrosion of copper.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2007