glow fuel Experiment with water contaminated nitro fuel

Wearing my chemist's hat now rather than a modellers' one-the usual method for drying methanol for 'general laboratory' use is storing it over molecular sieve 4A....which is a zeolite (a complex porous aluminino-silicate mineral) which can remove a variety of contaminants depending on the grade and pore size. [they-zeolites- have a wide variety of uses in industry and medicine]    For the drying of methanol they were quite effective-you added something like a tablespoon's worth to a normal 2.5 litre winchester...and left it for a couple of days before use. Now I am reluctant to advocate adding this stuff to fuel for several reasons:

     (1) it was not particularly cheap-so the cost of obtaining it might well outweigh the value of the recovered fuel (2) I am unsure how it would work in a tri-component or even four component fuel mix-it might well that the oil component will clog the zeolite and (3) being a mineral there will almost certainly be microparticulates that come off in use-these might pass through any fuel filter and hence pass into the engine where I doubt they will do it any good...

For the same reason I would advise caution in using silica gel-certainly never add it to the fuel. A package in the fuel jug cap is unlikely to cause any harm....though I'm unsure how much water it might absorb in that location.  If you make your own fuel, though there is a good case for storing your unmixed methanol over MS 4A or whatever proprietary product it is sold as these days. I should point out that it IS reusable-we used to periodically regenerate ours by drying in a lab oven at about 150-200C

A quick google search on 'molecular sieve 4A' will throw up a variety of information on prices, suppliers and properties.

    ChrisM
    'ffkiwi'

After reading some article on this subject I tell myself that I have little chance of succeeding in dealing with this Add another product that I have to filter how? I told myself that maybe it would be possible but I do not have the required skills Or material to do it I think I'll try something else To dilute it with other fuel I'll just want to spend the rest  It's a shame to waste fuel

There has been some anecdotal data and limited experimental work reported elsewhere RCU? RCG? to the effect that below a certain level, water in the fuel does no harm-and small amounts may even be beneficial....after all some WW2 piston engined fighters used water injection-and it was used for a time in car racing in the late 30's...and to rub it in-it was a water-methanol mixture.....sound familiar?

What relatively limited model aero engine data there is reports no deleterious effects until a certain point is reached-and then symptoms show up of poor idling, flameouts etc-all entirely what you would expect if you think about it-exactly what the original intent was with the big engines-to allow them to run cooler at higher boost pressures....so in our case eventually the incoming fuel charge contains enough water vapour that it quenches the plug....

Where we don't yet have adequate data-in the model engine sphere of engine operation are things like this:

(1) at what % water does the fuel start to cause problems? [will no doubt be partially affected by the TYPE of engine]
(2) starting with 0% contamination-over what time period and rate does the water level accumulate to levels where operation is affected? [will depend a lot on climate, time of year etc]
(3) how does normal handling-ie unsealing the container to pour or pump fuel influence the accumulation rate?
(4) what effects occur in long term storage where the container merely sits without external interference-[porosity, storage conditions, diurnal temp variation etc, container permeability]

All these things need serious work before meaningful conclusions can be extracted.

Finally-how do you accurately measure the water %.......being an analytical chemist by training ..i'd use a Karl Fischer titration-but that's not the sort of thing anyone does at a flying site..or even at home...

ChrisM
'ffkiwi'

When I mix my own fuel - typically 5-7 liters at a time - I split it to smaller storage containers, so when I replenish my field can, I allow the entry of damp air into only 1 of several storage containers...hence I do not infect my full inventory at every refilling occasion. Of course water ingress cannot be fully avoided, but my fuel remains usable up to the last drop.

Some time ago I read several article on this subject how to keep fuel well preserved and without contaminating them but sometimes it is Impossible to avoid it A container with a broken seal or a small hole made by mistake Sometimes the worst can happen forgetting an open container just for a flight For example in cold wet snowy weather I know it's already happened to many of us Having water in the gas is more or less good for certain aplication but not in cold weather Yes with a warmer plug it's better but it is very difficult to start the engine with water. I would like to have access to precise tools to measure it% water This would be useful to determine if it is really possible to remove a part by condensation or to measure at what levels it is acceptable after dilution ...Say these days I have fun with a big block this truck drink a lot of fuel I want to be able to use it, it's 30% nitro The truck likes 20% nitro, I'm going to mix it with 15%
The alcoholic truck

I don't understand why you worry that water would enter a closed container?
And why would the "condensation" be water and not methanol or nitro?

Surfer_kris wrote:I don't understand why you worry that water would enter a closed container?
And why would the "condensation" be water and not methanol or nitro?

plastic is porous and over time suck in moisture, but at this time since getting back into flying with cox engines im flying off a 15 year old quart of cox super power fuel with no problems

Yes, the time needed for glow fuel to go bad in its container is around 20-30years, in my experience.

At room temperature the vapour pressure of methanol is higher than the vapour pressure of water. So the air inside a partially filled bottle has more methanol than water in it. If you take a warm (room-temp.) bottle and bring outside in the cold, then these gases will condense on the cold wall of the container, that doesn't mean that there is any problem with water though.

The worst thing do is to have very little fuel in a container and open it outside on a warm day. The air entering the container then contains more water than the cold air does on winter day. One thing that one can do is to not store containers partially filled, as each time the air is replaced inside, there is a risk of introducing more water. It is the same principle as one would use on a regular car, always try to keep the fuel-tank nearly full, rather than nearly empty. Especially in seasons with rapidly changing air-temperatures.

On a similar note I think it would be worse to keep transferring the fuel between containers, as was suggested by the OP, that will just expose the fuel more to humid air, as compared to simply keeping it in a nearly full container.

As mentioned above; for Alcohol the molecular sieve 4A is a fairly expensive method for a hobbyist when pure methanol is relatively inexpensive. And is not viable for glow fuel mixtures

Remember water does not mix in gasoline, so we add Heet or similar products (a concoction of various alcohols) to deliberately "absorb" ( not a scientific term for the covalent bonding) and this mix of water laden alcohols then does kind of mix in the gasoline fuel and get converted to heat and water vapor in the exhaust.

A easier way to take contaminated alcohols with water "absorption" is simple distilling as we know from moonshiners; most alcohols vaporize at a much lower temperature (145F~174F) than water (212F) and are easily cooled from vapor back to liquid and captured

Of course this method is worthless for glow fuels compounded with various oils and Nitrogen's

I have many jugs of old fuel and all blending components....I am certain that when I open the methanol jug and pour what I need for my blend, that jug, and the meth in my beaker, are absorbing water from the air ( I only blend in AC controlled shop with as low a Relative Humidity as I can create easily, or in winter with real low RH)

rambling from an old home brewer and occasional (legal for personal use) moonshiner, ah, er, distiller

Take for example this syringe which is filled with humidity in a few minutes Leave in the cold on the front steps of the house To my surprise when I wanted to fill my little 4x4 truck

I was able to use it despite the contamination I simply added more fuel But I could feel the difference with the little truck Let's say that with a plane I wouldn't use this old fuel To avoid all possible problems
With an engine that stalls But hey, it's just a little experience to have fun maybe it will make a difference after all can be increase the nitro% who knows???

came to see I found the stopper full of metanol with the moisture I was able to shake it to get out a can the liquid whatever it is after burning it I could feel the remaining moisture Not to mention the smell that is to stay like in an old water canister stay in the sun for a very long time

Surfer_kris wrote:Yes, the time needed for glow fuel to go bad in its container is around 20-30years, in my experience.

.

did bot realize glow fuel would keep that long, that's good advice keeping ur fuel in smaller containers, defiantly gonna start breaking my gallons up into quarts, great advice man

Chase I buy my metal containers and food grade sealing lids from the Carry company, round quarts, square 1/2 and 1 gallon cans


https://www.thecarycompany.com/containers/metal/f-style-oblong-cans

Good Sherwin Williams paint stores usually only have empty square gallon cans and round Paint cans but I have seen other empty can types in some of their stores

Remember Relative Humidity is based on how much saturated water vapor there is in the air at certain temperatures

And also Light spectrums can and do chemically change some chemicals (like Nitro Methane) and is why most sellers of the pure product sell in opaque or Amber colored jugs/bottles.

So anticipating any LONG ....greater than 5 years the best is in air tight opaque containers kept in cool fry dark areas

That said the reality of RC and almost all other glow fuel hobbies the blended fuel is almost always in a clear jug or metal gallon can. Thousands of modelers go to the field all day long and leave the jug in the sunlight, rarely covering it with a towel and a LOT leave the jug open all day long. Rarely do they experience fuel related problems (except dirty fuel with grass , weeds n other crapped kicked up when the engines are running)

My point is...while it is very good practice to keep the fuel out of sunlight, keep it from getting HOT from the sun, and using filters to fuel the tanks, and always cap or close off the attached fuel hose....the reality is, direct sun and open to air does not really seem to be a big deal.

But to me it is just lazy or ignorant to not do it right....the stuff IS GETTING might Expensive

Guys like Ken cook over a long 3 day contest may burn up 1 to 3 gallons of fuel and certainly wants each and every engine run to be consistent and predicttable.....I know he is OCD about fuel managment

fredvon4 wrote:Chase I buy my metal containers and food grade sealing lids from the Carry company, round quarts, square 1/2 and 1 gallon cans


https://www.thecarycompany.com/containers/metal/f-style-oblong-cans

sidney crosby

thanks fred for the advice, i have a old fox missile mist can that has never had fuel in it that i was considering using at one time so i put a hand full of yard dirt in it so i wouldnt be tempted. thanks for the link, happy landings fredvon4