R.O. vs. D.I. vs. Tap Water when mixing MWF

After attending a MWF seminar in 2000, I was convinced that D.I. water was the best type of water for mixing coolant. The shop was in the country, and there were many dissolved minerals not to mention 'hardness' in what came from the well. Today, I work in a shop that is in a city. The municipal water is used 'as-is' in order to mix coolant - A couple of questions: 1) Do different types of coolant (e.g. Water Soluble vs. Synthetic) require different water? 2) As the city looks after chorination, fluoridation, hardness, etc., is there no advantage left for Deionization? 3) In order to minimize waste, would D.I. be a better choice to mix MWF, compared agains Reverse Osmosis?

Filed Under: 
Maintenance / Troubleshooting

Editor

Tue, 2011-09-06 16:33

Dear Reader,

I'll address your questions one at a time:

1. The sort answer to question is "no." Your coolant supplier should be able to formulate a product that will work in the water you have in your plant.  However, well water is the most troublesome since it will have consistency issues depending on weather conditions.  That being said still your coolant supplier should be able to formulate around that problem. 

2. If the city water is not causing you any problems then why go through the expense of buying a D. I. or RO unit?

3. I could devote a entire article to this question and I will so to answer this question, I will submit an article on the subject around the end of this week.

 All the Best,  Dom

rgauci

Tue, 2011-09-13 10:55

Thanks Dom, Your response clears things up - I look forward to your article regarding DI vs. RO Rob

Kenny Charnell

Mon, 2011-09-26 07:18

I have sold coolants in several Florida counties for years primarily to small to medium size job shops. The water issues I face are the most challenging part of my job. Municipal water sources changes from county to county, city to city. Chlorides added to the water supply being the biggest issue. They accumulate in the sump, and when they reach about 300 ppm + you can see surface rust on ferrous parts, tables, and vices. Add to that most small job shop owners are reluctant to make the investment in R. O. One thing that I encourage my shops to do that has helped a lot is to get them to run their source water through an inline carbon filter system. They can buy them at Lowe's or Home Depot. Whirlpool makes one with 1/2 inch inlet/outlet that they can pick up at Lowe's with two carbon filters for about $50. It ain't R.O. or D.I. but it is an improvement over what comes straight out of the tap. The "cheeses" that build up in the corners of the machine diminish, and rust issues go away. Of course a lot depends on the type of coolant they use, but my customers and I have definitely seen an improvement. As often is the case with the human animal when they see water quality is an issue they cam affect, then they step up to R.O., D.I, or larger filtration systems.