How Do I Test for Acidity?

Testing for acidity is actually pretty easy. All you need is a Bromothane™ test kit, some eye-hand co-ordination and a little patience. It's actually pretty simple and very interesting.

One of the reasons you won't have a problem with this test is because you are going to get the best technical support in the business from MicroCare, and we will teach you how to conduct this test properly and avoid any problems.

But just in case you missed class that day, here's a summary of the acid acceptance test procedures.

• Setting Up the Test •

The acid acceptance test is a simple chemical test which determines (a) if you need to add BromoBooster™ and (b) how much BromoBooster™ you need to add. The entire test takes about 15 minutes to perform. We recommend testing weekly, and keeping a log book of your results.

To begin the test, you need the acid acceptance test kit which is available from MicroCare as the BromoTest™ kit. The BromoTest™ kit contains everything you need to conduct the simple test. Again, a strong background in chemistry is not required. In fact, no background in chemistry is required. Just follow these steps.

The photo on the left shows the contents of the BromoTest™ kit. It includes two small bottles of chemicals, an eye dropper to collect solvent samples, a mixing tube and the instructions. Not included is a small sample of your solvent (shown in the photo as a gallon jug of solvent, which really is far more than you need) and a watch or kitchen timer.

Begin the test by collecting a small sample of your solvent from your degreaser. We recommend you collect the sample from the water separator, the spray wand or the rinse sump (which is the cleanest solvent). Using solvent from the boil sump -- which is where all the contamination is concentrated -- can produce inconsistent results. Make sure the sampling jar into which you put the solvent is clean and water-free. Typically, a sample of 200 mL (about half a pint) is more than sufficient. Let the solvent cool to room temperature.

• Conducting the Test •

To begin the test, use the eye dropper provided in the kit and remove 1.5 mL of solvent from the sample jar. Carefully deposit your sample into the snap-lid container.

It's important to know that you MUST use the eye dropper supplied with the kit only. Here at MicroCare we have tried several other "graduated" eye droppers and they ALL measured different quantities of liquid. Different eye droppers will yield different results. Since the test is calibrated for exact quantities of solvent and test solutions, use the eye dropper provided with the kit.

In the same line of thought, you need to be very precise in obtaining 1.5 mL -- the whole test is calibrated to a 1.5 mL sample. This is complicated by the fact that the solvent has some surface tension. This means the solvent will "crawl" slightly up the inside wall of the eyedropper, creating a curved bubble near the top of the eye dropper. The bubble is the solvent-air interface and is called the "meniscus" (red arrow, photo left). Take your measurement of 1.5 mL from the BOTTOM of the meniscus. Practice this a few times until you can obtain a sample of precisely 1.5 mL in the snap-lid container. 

• When You Get a "Whoops!" •

From time to time you are going to mis-measure your samples or add the two solutions incorrectly to the sample. Should this ever happen, you need to clean the snap-lid container carefully and start again. But there's a trick to cleaning the snap-lid container, too!

You see, the whole point of this test is to control the amount of water in your solvent. If you clean the snap-lid tube but don't dry it carefully you will add water artificially to your test sample, skewing the results unpredictably. So, go ahead and clean the snap-lid container with water. Do not use any solvent and for heaven's sake don't use soap. Just pure, clean tap water will work fine.

Then -- and this is the trick -- take a paper towel and curl it into a tube. Stick the tube of paper in to the snap-lid container and carefully dry the inside of it. Be sure to clean the lid itself, making an effort to remove any excess water. We urge you to repeat the process, to make sure the snap-lid container is totally dry and water-free. If you have a can of "canned air" around, you can also use that to blow-dry excess water from hard-to-reach crevices.

• Adding the First Drops of the Test Solution •

The next step is to add Solution A to the sample. This is the yellow liquid in the bottle with the red label. Supplement your sample of Bromothane™ with enough Solution A until the you have 3.5 mL of liquid in the snap-lid container. Hold the bottle at approximately a 45° angle to provide the maximum consistency between drop sizes. Add Solution A slowly, because if you add too much and go beyond 3.5 mL you have to throw out your sample and start again. Do not shake the container during the addition of Solution A.

Again, the liquid forms a meniscus in the plastic snap-lid container. For maximum precision, you want the BOTTOM of the meniscus to just touch the 3.5 mL graduation mark on the snap-lid container.

Once you have added the proper amount of Solution A, tightly cap the bottle of Solution A. Snap down the lid on the snap-lid container and lock the safety tab in place. Shake the container for 10-20 seconds to thoroughly mix the contents. Check the time or start your kitchen timer, and let the sample rest for 10 minutes. Take a break!

It's funny how very sensitive this test can be, and this ten-minute break is a good example of how slight variations in your procedures can produce unusual results. If you cut the "resting period" short, you definitely will get erroneous results. If you wait too long -- say, more than half an hour -- your results may be flawed. So don't short change the ten minutes, but don't wait too long either. And be as consistent as possible between your weekly tests.

• Monitoring for the Color Change •

After your brief break, we're ready to finish the test. Take the bottle containing Solution B -- the green labeled bottle -- and start adding liquid to your test sample. Add the liquid drop-by-drop. Count each drop until the solution turns bright blue.

Here's a few tips for adding Solution B.

• Hold the bottle at approximately a 45° angle to provide the maximum consistency between drop sizes.

• The color change happens quickly. After each drop, close the lid on the snap-lid container and give the mixture a brief shake.

• Do not use your thumb to seal the top of the test mixture in place of the snap-lid: the contamination on your fingers could affect the test results.

• Typical results are between 23 and 33 drops. If you're into the 40s or more, you either did something wrong or your solvent is literally "off the charts" with acidity.

• Always record your results into a log book.

• Discard the sample in a manner approved by your company's management.

• Determining the Quantity of BromoBooster™ to Add •

The Test Kit instruction package includes this conversion table:
 

The object of this game is to compute the number of gallons of BromoBooster™ required to bring the solvent back into an acceptable degree of acidity. To perform this task, multiply the factor from the table above by the number of gallons of solvent in your degreaser.

Here's an example. Suppose your degreaser holds 150 gallons of Bromothane™ S, and your test results show that it took 30 drops of Solution B to turn the sample blue.

The factor from the Bromothane™ S table for 30 drops is 0.052. Multiply 150 by 0.052 and you get 7.8. So add 8 gallons of BromoBooster™ and your system will be in fine shape.

When adding stabilizer, allow the system to cool to room temperature before adding the solvent. And don't just dump the BromoBooster™ into the machine. After the degreaser has cooled, add the BromoBooster™ and any fresh solvent into the "condensate" or "rinse" sump. This will allow for faster mixing throughout the system. In addition, it will be safer. Remember that BromoBooster™ is flammable (although Bromothane™ solvents are not). By adding the flammable BromoBooster™ to the largest, cleanest volume of solvent the solvent will quickly dilute the flammable stabilizer and inert it.

After adding the booster, run the machine for two hours to allow the mixture to stabilize. Then, do ANOTHER acid acceptance test to be sure all your measurements were correct. If all is well, then go ahead and return the machine to production.

 There should be some reference on where to add the BromoBooster to ensure safety and maximum effect.

One other note worth mentioning. The Bromothane™ Acid Acceptance Test is designed only for Bromothane™ solvents and the stabilizer package we use. MicroCare cannot predict it's accuracy or effectiveness on solvents and stabilizers from other companies.

Click here for these instructions in pdf format.

Updated: Dec. 21, 2004
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The term "Bromothane", "BromoBooster", "BromoTest" and the Bromothane logo are trademarks of MicroCare Corp.