Question on topping off coolant

[CNCPlastic]

I'm using a synthetic water based coolant and seem to lose about a gallon every week to two weeks presumably mostly to evaporation. My question is, are both the coolant and water evaporating or just the water? I wonder if my concentration of coolant is getting stronger and stronger if I'm losing mostly just water. Too bad they don't make a test device like they have for automotive antifreeze mix.

[JFettig]

depending on how much you got going on there and all, but it could be steaming out, then some coolant goes with it, I ususally just add water. At work in some of the lathes when they get run for full 8hrs on fast parts, I add 5-10gallons of water and a little bit of coolant a day. Its not too good for the health

They do make a testing device, It works quite nicely but I beleve its quite spendy. We have one at work I just guess at home
An easy way to check, is make it so you can feel the lube, but its not gooey. Right away when you first make a new batch, it shoudl be slightly clear, like you can see through a layer of it, but not through a lot of it. later it turns more white and stays white unless it gets oily and stuff.

Heres a pic of my early flood setup:
http://jfettig.wc101.com/cnc/flood1.jpg
Its just slightly thin but it thickened soon enough.

Jon

[DAB_Design]

The tester is called a refractometer. You can get them off ebay. Here's a quote out of one auction "CAN BE USED TO MEASURE THE CONCENTRATION OF ANY SUGAR BASED LIQUID OR METAL WORKING COOLANT." Not sure of exactly what it can be used with. But this auction is a 'Buy if Now' for $20. Measures up to 10%. auction # 3842846383. 8 still available.

[sol]

I know nothing about coolant but I do understand specific gravity and that is all that cheapo antifreeze gauges measure. Seems like it would be worth a try to just calibrate an antifreeze gauge with different concentrations of coolant mix.... only costs $1. 48