# 3 Weak Machine Coolant and Extreme Bacteria Growth

There are many reasons to filter machine coolant other than to filter out particles that can potentially damage tools and equipment.  Filtering Machine Coolant also prevents bacteria from growing, creating a safer work environment.  Refer back to the Coolant Index for more information on Filtering Coolant and Machine Coolant Properties.

The machine coolant used is much too weak.  It is being used at the level of make –up coolant.  Machine coolant is ordinarily mixed in the range of 20:1 to 30:1.  Water evaporates faster than machine coolant so the make-up machine coolant is largely water and is usually mixed about 10% of the level of new machine coolant.   You need to add additional machine coolant since the rust prevention, lubrication and bacteria control properties in machine coolant get used up. 

Bacteria Tests

The bacteria and fungus levels are very high because the coolant concentration is much too low.  The cobalt levels are too high in some units and you need to use cobalt remover and filter system to reduce the cobalt levels. 

Standards

Coolube 220 

pH above 8

Refractometer  2.4 – 3.6

Bacteria – suggested action level   100,000 or higher

Fungus   suggested action level   1,000 or higher

Tramp oil

Particulate

Cobalt – suggested action level Boeing standard is 10   

Test Results

Cobalt - Grinders 2, 3 & 4 tested high for cobalt

All four grinders tested high for Bacteria

All four grinders were much too low for concentration (Refractometer)

All four grinders were very good for tramp oil and particulate matter. 

Use of Triadene

Triadene can be used safely but it needs to be used carefully.  Proper coolant concentration should eliminate or greatly reduce the need for Triadene 

Sampling Results - Done October 22, 2005

The major problem is that the coolant was much to weak.  The Refractometer readings should have been about 5.0 instead of just a fraction of that.   Instead of suing coolant concentrate and diluting it they were using makeup coolant that had already been diluted 10:1.