Ethanol testing kit?

[rezaf_2000]

What's a good ethanol testing kit that you use to verify pure auto-gas?

Yesterday I visited about 9 of the gas stations in my city, out of which 6 were labeled as "may contain up to 10% ethanol". According to Illinois law, gas stations selling ethanol blended fuel should label it, but I guess lack of a label is not proof positive that the gas is suitable for aviation purposes. Therefore, I guess it's better to test them out. Hence, please share the ethanol testing kits you use and like (or the ones you don't). I found this one which promises good results, but is a bit pricey.

(The purpose of this exercise is to make sure I will have a few options in town to get cheap mogas if I were to buy a mogas compatible airplane in the near future).

[Merlinspop]

Chances are you'll find that signs that say "May contain up to..." might as well say "Contains..." And even if you find it doesn't today, it might tomorrow, so you can't depend on it.

You can test without a "kit":
1- Pour a small amount of water into a narrow jar (an olive jar works great) and mark the water level with a Sharpie.
2- Add the fuel to around a 10:1 fuel:water ratio.
3- Shake well, let settle for a few minutes.
4- See if the water level has risen above the mark. If it has risen, it has combined with ethanol from the fuel.

[drseti]

Bruce's technique works just fine to determine if the fuel contains any ethanol. The difference with the expensive testing kits is that they quantify the exact percentage. Probably not necessary, since anything over 0% ethanol is, for me, disqualifying.

[MrMorden]

I have a calibrated fuel drainer/tester. You put a small amount of water in with some fuel, shake it, and let it settle. It reports percentage of ethanol, and costs $6 at Aircraft Spruce:

http://www.aircraftspruce.com/pages/ps/ ... Tester.php

[Wm.Ince]

I have a calibrated fuel drainer/tester. You put a small amount of water in with some fuel, shake it, and let it settle. It reports percentage of ethanol, and costs $6 at Aircraft Spruce:

http://www.aircraftspruce.com/pages/ps/ ... Tester.php

Thank you for the link, Andy.

[MrMorden]

I have a calibrated fuel drainer/tester. You put a small amount of water in with some fuel, shake it, and let it settle. It reports percentage of ethanol, and costs $6 at Aircraft Spruce:

http://www.aircraftspruce.com/pages/ps/ ... Tester.php

Thank you for the link, Andy.

Sure thing...a friend turned me on to that tester. It takes about 30 seconds to test a fuel sample, and is accurate to 1/2% to 1%, depending on how good your eyes are at reading distances.

[drseti]

http://www.aircraftspruce.com/pages/ps/ ... Tester.php

It looks to me like just a standard fuel sampler, with the addition of calibration marks for measuring ethanol. I would assume you add water to one line, fuel to a second line, shake, and let it settle. Then, you check the dividing line between water and fuel. Its level would reveal how much of the water was absorbed into the fuel, which could then be correlated to ethanol percentage. Am I right?

If so, one could use any existing fuel sampler, just by adding the required lines with a Sharpie (assuming one knew where exactly the lines should go). Seems there should be an article out there somewhere which reveals the secret dimensions.

[MrMorden]

http://www.aircraftspruce.com/pages/ps/ ... Tester.php

It looks to me like just a standard fuel sampler, with the addition of calibration marks for measuring ethanol. I would assume you add water to one line, fuel to a second line, shake, and let it settle. Then, you check the dividing line between water and fuel. Its level would reveal how much of the water was absorbed into the fuel, which could then be correlated to ethanol percentage. Am I right?

If so, one could use any existing fuel sampler, just by adding the required lines with a Sharpie (assuming one knew where exactly the lines should go). Seems there should be an article out there somewhere which reveals the secret dimensions.

That is correct. Making your own sounds like more than $6 worth of work for possibly incorrect results to me.

[designrs]

I use a similar tester to the one that Andy referenced. It's accurate. In my experience it matches the gas stations that I tested. Those that advertised "up to 10 percent" were 10%. One gas station that I use regularly that is "ethanol free" really is ethanol free. Whooo hoo!

[zaitcev]

https://www.amazon.com/Ajax-Scientific- ... 00EPQ5A50/

I went a step up over Andy's suggestion and bought a 10 mL graduated cylinder. Additional advantage of it is that it's free-standing, so you can pour water into it easily without jiggling. The diameter of 10 mL cylinder is just right to cork it with your thumb. An olive bottle is much too big. Remember that you have to dispose of the mix, so unless you have a Gatts jar, it's a problem.

{Correction: my cylinder is actually 50 mL}

[drseti]

The diameter of 10 mL cylinder is just right to cork it with your thumb.

Unless you have a small thumb.

Good that it's metric, since 1 ml = 1 cc. How many ml of water, and how many of petrol, do you typically add to test?

[zaitcev]

Good that it's metric, since 1 ml = 1 cc. How many ml of water, and how many of petrol, do you typically add to test?

Sorry, I forgot the details. My cylinder is actually 50 mL, not 10. I fill it with 40 mL of gas and 10 mL of water. The more gas you have, the more the division moves, so you can reliably detect smaller amounts of ethanol. The division surface is not very exact and the surface (meniscus) is not flat where it touches the walls. In my case, I am not interested in exact measurement, but I want to know if there's ethanol.

[rezaf_2000]

Chances are you'll find that signs that say "May contain up to..." might as well say "Contains..." And even if you find it doesn't today, it might tomorrow, so you can't depend on it.

You can test without a "kit":
1- Pour a small amount of water into a narrow jar (an olive jar works great) and mark the water level with a Sharpie.
2- Add the fuel to around a 10:1 fuel:water ratio.
3- Shake well, let settle for a few minutes.
4- See if the water level has risen above the mark. If it has risen, it has combined with ethanol from the fuel.

Thanks, I'm going to try this later today. A couple of questions:
Edit: I did the experiment, here are the answers.

1. Is the 10:1 ratio important? Other places on the net I read 3:1.
Edit: It doesn't seem to matter much. The more gas the merrier, the impact of the test becomes easier to read.
2. Should I top off the bottle to the max with fuel, or once a ratio of fuel to water is there, it's enough. A.k.a, does air in the bottle invalidate the experiment?
Edit: No, it doesn't seem to matter at all

[rezaf_2000]

Gas station #1: a bust. Even though it doesn't show the proper label, the gas seems to have 10% alcohol.

[3Dreaming]

The labels can often be hard to spot.