Refractometer

[l u k e]

I need to purchase a refractometer and don’t know anything about them. Can I get by with a cheapie or do I have to spend more to get something worthy?

Also, are these things universal or do I have to buy one just for coolant?

I was looking at this one for $30 on eBay but don’t know if it's a waste of money.

[PixMan]

Close, but not quite. Look around some more. You want one that can handle at least 0-32 brix if you're checking machine coolants.

[l u k e]

Thanks, I picked up what you suggested. These are pretty cool, I've never seen one before.

[PixMan]

Now that you've got one, it's important to understand how to use it. First, calibrate it using (if at all possible) distilled water. If not distilled, use only clean bottled water to "zero out" the reading.

Now, depending upon what type, brand and specific product of coolant you are using, there will be a correction factor to use. For example, a fairly pure soluble oil coolant will read with a 1.0 to 1.2 factor. Most semi-synthetics will use a 1.6 to 2.0 factor. What that means is that if you read 5% concentration, multiply your reading by (for example) 1.7 and that "8.5" result is the corrected reading of the concentration of your coolant.

Your coolant supplier should be able to give you the correction factor for their product.

[l u k e]

Thanks, I didn't know the reading had to be refactored. I'm using Trim Sol E206, it's soluble oil.

Edit:
Just sent an email to Master Chemical to get that info.