Testing the Testing of Mogas

Have you tried the test in gas with ethanol?

Nope.

That's next!
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"Jay Honeck" wrote in message
oups.com...
[...]
There are a few questions yet to answer

1. Since isopropyl alchohol is 95% pure, that means that it is 5%
water. Is the tablet fizzing only because of the 5% water?

You can buy "anhydrous isopropyl alcohol". That is, greater than 99% pure.
It may well be technically impossible to get 100% pure alcohol, due to the
presence of water vapor, but obviously the amount of water available in the
air isn't enough to get the tablet to fizz, since it would carry a similar
amount into the regular gasoline with it when you dropped it into there, and
it didn't fizz at all in that.

So, IMHO question #1 is easily answered.

I'm not entirely sure I'm buying the "isopropyl alcohol and ethanol are
chemically similar enough" argument, but I definitely didn't minor in
chemistry, and that was a long time ago. I'm skeptical simply out of
nature, not because I have any real reason to disbelieve Mary's assumption.
Note, however, that they are chemically different enough that one can kill
you right away in small amounts, while the other may take years and years
except in very large doses.

2. However, even if this were the case, would it not also be true that
the presence of ethanol in the car gas would ALSO introduce water, and
thus fizz the alka-seltzer regardless? In other words, is it
irrelevant that the alka-seltzer might only be fizzing because of the
water, if water always accompanies alcohol in gas?

See above. IMHO, while alcohol may bring with it some small quantity of
ambient water vapor absorbed by it, I would be surprised if it were enough
to affect the results of your test. Furthermore, I agree that if a freshly
opened bottle of anhydrous isopropyl alcohol absorbs enough water to be the
sole reason for the tablet fizzing, then surely the alcohol present in gas
would have absorbed enough water to cause the same to happen.

Either way, the fizzing would indicate the presence of water OR
alcohol, or just alcohol that is "saturated" with water -- both of
which would indicate a "No Buy".

Right?

Sure. Though, I'd say that if you need an Alka-Seltzer to tell you that
there is just water in the gas, you're not really trying. Seems to me it's
the alcohol you really care about.

Pete

"Jay Honeck" wrote in message
oups.com...
Plop-plop, fizz-fizz... :-)

In a previous thread I outlined the new (vastly more convenient)
"alka-seltzer method" of testing your mogas for both ethanol and water
-- but (for those who missed it) here it is again:

1. Tap a few ounces of suspect gas into a cup
2. Drop 1/4 of an alka-seltzer into the gas
3. If no fizz, no alcohol or water is present, and the gas is "good"

The question was/is: Is it chemically valid to expect alka-seltzer to
fizz in the presence of alcohol?

Mary (with her minor in chemistry) and I (with my English degree that
allows me to, er, write about this) devised the following empirical
test:

Part I:

1. Purchase a bottle of 95% pure isopropyl (rubbing) alcohol. While
it's not ethanol, Mary determined that the chemical make-up is similar
enough for this test.

2. Pour a few ounces into a cup.

3. Add 1/4 tablet alka-seltzer to the alchohol.

4. Observe results.

** Sure enough, the tablet instantly starting fizzing.**

Part II:

1. Go to gas station we always buy our gas from.

2. Pump a few ounces into a cup.

3. Add 1/4 tablet alka-seltzer to the cup.

4. Observe results.

** Sure enough, the tablet just sat there -- no fizz.**

Part III:

1. Add some alchohol to aforementioned cup of gas, approximating a 10%
mixture.

2. Observe results.

** Sure enough, the tablet instantly started fizzing, verifying that it
WOULD fizz if there were alcohol in the gas. **

There are a few questions yet to answer

1. Since isopropyl alchohol is 95% pure, that means that it is 5%
water. Is the tablet fizzing only because of the 5% water?

2. However, even if this were the case, would it not also be true that
the presence of ethanol in the car gas would ALSO introduce water, and
thus fizz the alka-seltzer regardless? In other words, is it
irrelevant that the alka-seltzer might only be fizzing because of the
water, if water always accompanies alcohol in gas?

Either way, the fizzing would indicate the presence of water OR
alcohol, or just alcohol that is "saturated" with water -- both of
which would indicate a "No Buy".

Right?
--
Jay
others have already commented on the alka seltzer chemisty, but a simpler
and quantitative way of measuring how much alcohol is in the fuel is to
simply mix it with water. Try 9 parts of fuel to 1 part of water in a
graduated cylinder. the alcohol will migrate to the water phase so you will
see an increase in the height of the water layer at the bottom and a
decrease in the height of the fuel layer if there is significant amount of
alcohol..
terry

And for all you wannabe chemists out there... Denatured alcohol
(ethanol plus a bit of methanol) is available everywhere... I have a
quart stting in front of me on my desk I picked up at the hardware
store... I use it for cleaning my glasses, camera lenses, etc..

Get 100 cc of gasoline, add 10 cc of denatured alcohol from your
favorite Home Depot, etc., add 1/4 tab of "plop, plop, fizz, fizz" and
observe... If it fizzes then you know that the test is valid as your
mixture is "gasohol"...

denny - minor in B.S., major in Obfuscation...

I believe a number of different chemicals are used to denature ethanol.
Benzene for one.


Denny wrote:
And for all you wannabe chemists out there... Denatured alcohol
(ethanol plus a bit of methanol) is available everywhere... I have a
quart stting in front of me on my desk I picked up at the hardware
store... I use it for cleaning my glasses, camera lenses, etc..

Get 100 cc of gasoline, add 10 cc of denatured alcohol from your
favorite Home Depot, etc., add 1/4 tab of "plop, plop, fizz, fizz" and
observe... If it fizzes then you know that the test is valid as your
mixture is "gasohol"...

denny - minor in B.S., major in Obfuscation...

others have already commented on the alka seltzer chemisty, but a simpler
and quantitative way of measuring how much alcohol is in the fuel is to
simply mix it with water. Try 9 parts of fuel to 1 part of water in a
graduated cylinder. the alcohol will migrate to the water phase so you will
see an increase in the height of the water layer at the bottom and a
decrease in the height of the fuel layer if there is significant amount of
alcohol..

Thanks, but this is precisely the test procedure I'm trying to
eliminate.

Carrying water around in "The Mighty Grape", and sitting at my gas
station pumps while pouring water and gas into a beaker, and shaking
it, is just too much of a pain. People in line behind me must really
wonder what the HECK I am doing! :-)

If I can get away with simply dropping a tablet in the beaker, I will
(a) eliminate the water, and (b) speed things up considerably.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

In article om,
"Jay Honeck" wrote:

Carrying water around in "The Mighty Grape", and sitting at my gas
station pumps while pouring water and gas into a beaker, and shaking
it, is just too much of a pain. People in line behind me must really
wonder what the HECK I am doing! :-)
If I can get away with simply dropping a tablet in the beaker, I will
(a) eliminate the water, and (b) speed things up considerably.

After performing the test, and the fizzing commences, pour the contest
of the test tube into your tank. When they ask you what you are doing,
tell them you have discovered a magic tablet that allows you to put
water and the tablet in your tank and make your own gasoline. What they
saw you doing was testing to make certain you had the correct
proportions.

"Jay Honeck" wrote in message
ps.com...
others have already commented on the alka seltzer chemisty, but a simpler
and quantitative way of measuring how much alcohol is in the fuel is to
simply mix it with water. Try 9 parts of fuel to 1 part of water in a
graduated cylinder. the alcohol will migrate to the water phase so you
will
see an increase in the height of the water layer at the bottom and a
decrease in the height of the fuel layer if there is significant amount
of
alcohol..

Does this mean that you can use water to REMOVE alcohol from mogas?

Fill the mighty grape. Pour in a gallon of water. Drive around to mix. Drain
the water. Ta-Da.

Al G

"Al" wrote in message
...

"Jay Honeck" wrote in message
ps.com...
others have already commented on the alka seltzer chemisty, but a
simpler
and quantitative way of measuring how much alcohol is in the fuel is to
simply mix it with water. Try 9 parts of fuel to 1 part of water in a
graduated cylinder. the alcohol will migrate to the water phase so you
will
see an increase in the height of the water layer at the bottom and a
decrease in the height of the fuel layer if there is significant amount
of
alcohol..

Does this mean that you can use water to REMOVE alcohol from mogas?

I guess it does but I wouldnt reccommend this to anyone. Interestingly we
had a major fuel contamination issue in australia in 2000 which grounded
half the GA fleet , a corrosion inhibitor , diethylamine which was supposed
to be washed out of the fuel before sale, wasnt removed properly . it
reacted with brass in the fuel systems to form a black gunk which caused
some engine failures. fortunately no one was hurt ( other than financially).
the solution was to just wash the stuff out with water.
terry

"d&tm" wrote in message
...
others have already commented on the alka seltzer chemisty, but a simpler
and quantitative way of measuring how much alcohol is in the fuel is to
simply mix it with water. [...]

I'm guessing you didn't see the earlier thread, but...your procedure is
where this all started. Jay even referenced it in his previous Alka-Seltzer
thread, when he wrote:

we have used the "water/gas/shake" test to verify that
there is no ethanol present. I find this method to be
rather imprecise and quite a pain

So, here's a gentle "yes, we already know" in reply to your suggestion.

Jay is attempting to come up with a test that is more foolproof, easier,
less messy, whatever.

Personally, I'm not sure that even if the Alka-Seltzer method works, it's
superior to the water-mixing method. After all, if you test by mixing
water, you just have gasahol with some water in it. You can even strain the
water out using a GATS jar if you want to use it (if the test is positive,
then in something that can tolerate ethanol, of course...like your car). If
you test it with Alka-Seltzer, now you've contaminated your fuel with an
Alka-Seltzer tablet. At the very least, you've a fuel-soaked tablet you
need to dispose of, and I'm not sure that the fuel is usable at that point,
ethanol or not. Just because the tablet didn't fizz, that doesn't mean
there aren't bits of it in the fuel.

Assuming this doesn't already exist, I think it's only a matter of time
before you can buy a fuel testing kit that is either just strips you dip
into a fuel sample, or drops you drip into a fuel sample, and which tells
you with a change of color whether there is ethanol or not in the fuel.
Either the water mixing OR the Alka-Seltzer just seems too unwieldy to me to
be practical in the long run.

Pete