How to Correctly Use a Refractometer Video Transcript
How to Correctly Use a Refractometer Video Transcript
Scenery: A man in glasses and a black QualiChem vest stands in front of a lab table and addresses the camera.
On screen text: John Wiley, Director of Global Marketing.
John Wiley: Hi, my name is John Wiley, and I’m the Director of Global Marketing at QualiChem. Today, we’re gonna talk to you about how to correctly use a refractometer.
Ambient sound plays.
Scenery: QUALICHEM logo fades from white to blue and green on a white background.
Xylophone music plays.
Scenery: John reappears on screen in front of a lab table and addresses the camera.
John Wiley: Refractometers are a tool that you use to measure the concentration of your coolant used for machining or grinding. Customers will buy a concentrate, dilute it with water to create the coolant itself. The concentration of the coolant is important, because that’s how we control cutting performance or grinding performance, how we control rancidity, how we control staining and corrosion…so it’s really important that your metalworking fluid, your coolant, is in the correct concentration range.
Scenery: Blue text appears above a solid green line on a white background. On screen text reads: Which type of refractometer should I use?
Scenery: John reappears on screen in front of a lab table and addresses the camera.
John Wiley: We’re often asked what type of refractometer to use, so we’re going to start with that first. There’s generally two types of refractometers: the traditional, analog-style refractometer and more and more shops and companies today are going to the digital-style refractometers.
What we suggest that you consider when you purchase a refractometer..number one is most important, is the ability to calibrate that refractometer to make sure, like all the other gauges in your shop, that what you’re measuring is accurate.
Upbeat techno music plays.
Scenery: Blue text appears above a solid green line on a white background. On screen text reads: How do I calibrate my refractometer?
Scenery: John reappears on screen in front of a lab table and addresses the camera. He is holding a refractometer.
John Wiley: Okay, so you have refractometers that can be calibrated. How do you calibrate them? So, with the analog unit, it’s pretty simple. Flip open the lens, put a sample of the water that you’re going to be using to mix the coolant onto the lens, cover it, see what the reading is…this one is slightly above zero. The analog units usually come with a little screwdriver device…calibration hole here, and we are exactly at zero now. That one is calibrated.
On the digital units, it’s a similar process. Open the lens cover, put some of the water that you’re going to be using to make the coolant on the lens, power the unit on, select from the menu the ‘zero out’ feature, and then set to zero. And your digital refractometer is calibrated.
Scenery: Blue text appears above a solid green line on a white background. On screen text reads: How do I read my refractometer?
Scenery: John reappears on screen in front of a lab table and addresses the camera.
John Wiley: In addition to having a refractometer that can be calibrated, the other important characteristic is the scale in which the refractometer reads.
Scenery: John holds a piece of paper up to the camera depicting a large blue circle with a light blue rectangle inside containing what appears to be a temperature gauge, a sort of visual scale to represent the scale of the refractometers.
John Wiley:In this particular scale, it goes from 0 to 30, which in most cases is probably too broad a range for metalworking fluid. The refractometers–the analog variety–go from zero to 10 and zero to 20. The digital refractometer, there is no scale, you get the actual percent…bricks reading on the face of the refractometer.
Okay, so you have your refractometer, hopefully one that can be calibrated, whether it’s analog or digital. One of the important things to understand is coolants are designed to be used at a certain percent by volume. Again, some coolants have a minimum concentration of 5%, maybe a maximum of 12%. Refractometers don’t measure percent by volume…refractometers measure in something called percent bricks.
Bricks was a unit of measure when refractometers were first developed. They were designed to measure sugar in water. So, bricks is an old unit…I forget the exact calibration..one millimeter of sugar to one liter of water. That’s really irrelevant for us, what’s important is the reading that you get when you’re looking at the refractometer..the digital value that you get.
Scenery: John holds up a data sheet with lines of text on it.
John Wiley: So, every coolant is a little bit different. Refractometers, in simple terms, measure how much stuff you have in water, so what needs to be considered is how much water is in the concentrate of the product itself. So, here we have a semi-synthetic.
Scenery: Camera zooms in on data sheet.
On screen text: XTREME CUT 250C Semi-synthetic Refractive Index -1
John Wiley: It’s an oil-based product. On the data sheet for this product, refractive index is 1. So, if in this particular example, I have a refractometer reading of 5
Scenery: Animated temperature scale appears on a dark gray background. The top of the scale is 20 degrees celsius, and the bottom reads “Brix%”. The scale goes from 30 to 0 on each side.
John Wiley: My concentration, the calibration is one, so I’m at five percent by volume.
Scenery: John reappears in front of a lab table and addresses the camera.
John Wiley: Some coolants have refractive indexes that are greater than one, because there’s a higher percentage of water in the concentrate. Q-Cool 330
On screen text: Q-COOL 330, Full-synthetic, Refractive Index-2.9
John Wiley: It’s one of our full synthetics, there’s no oil, there’s a percentage of water in the concentration.
Scenery: Camera zooms in on data sheet.
John Wiley: On this particular product, we have a refractive index of 2.9. So, again
Scenery: Animated temperature scale appears on a dark gray background. The top of the scale is 20 degrees celsius, and the bottom reads “Brix%”. The scale goes from 30 to 0 on each side.
John Wiley: if we go back to the example, if this five reading was for the Q-Cool 330, I would have to multiply that five by 2.9, which is going to be roughly 14.5% by volume.
Scenery: John reappears in front of a lab table and addresses the camera.
John Wiley: So, this..the idea of converting a refractometer reading causes some people confusion. What’s important is you work with your coolant supplier, understand what the refractive index is for the product you’re using, and then multiply that refractive index by what you’re actually reading on the refractometer.
Scenery: Blue text appears above a solid green line on a white background. On screen text reads: How do I use my refractometer?
Scenery: John reappears in front of a lab table and addresses the camera.
John Wiley: Okay, so the video today was about how to use a refractometer. We covered how to calibrate one, how to understand the scale, what a refractometer is actually measuring. So, how do you use a refractometer?
So, here, normally, in most situations, you’re going to be taking the sample from your machine tool. Typically, the best place to do that is from the coolant nozzle after allowing the coolant to circulate for a couple minutes. So, we’ll pretend this sample is from a machine tool, take the eye dropper, put some coolant on the lens, close the cover, and I’m looking at 7.5% on this scale, which earlier I mentioned XTREME CUT 250 is a direct read, so 7.5 on the refractometer is 7.5% by volume.
Now, it gets a little bit different, as mentioned earlier, with Q-COOL 330. It’s an oil-free product with a refractive index of 2.9. So, taking a sample of this, clean the lens off, put some of the Q-COOL 330 onto the lens, measure the concentration. So this is reading about 2.5…so 2.5 times 2.9 is going to give you roughly 7% by concentration.
So, that’s the critical difference is in understanding that, with a product that requires a conversion from the refractometer reading to percent by volume…that you understand that. Because, as I mentioned, all coolants are designed to operate in a given percent range by volume. So, the product data sheet you might get from your supplier, and we provide all this information…our XTREME-CUT 250, for example, for machining, 7-9% by volume. So, your refractive index should be somewhere between 7 and 9.
On the Q-COOL 330, being the full synthetic, you know, your typical operating range for machining will be anywhere from maybe 4-8%. But, when you’ve got a refractive index of 2.9, your reading is going to be somewhere around 1-3% on the refractometer.
Okay, so hopefully you know a little bit more about refractometers. How to use them, how to calibrate them, what they’re actually reading, and how to convert that reading into a percent by volume. It helps you keep your coolant in good condition and your machining and grinding applications performing the way they need to.
All of us at QualiChem are happy to help you with your metalworking fluid selection, use, and maintenance. Maintenance includes use of a refractometer. If you have any questions about anything we’ve covered today, please reach out and we’ll make sure you get taken care of.
Screen fades to black.
Music ends.