Hi. I have an un-opened gallon of Cool Power 15% that is at least 2 years old.

Still good?

If it's been unopened and kept inside it will be just fine.

Ken

Stored correctly even opened bottles will last forever and ever.

Get a fresh bottle and mix half new and half old and you should be good to go.

If the bottle has never been opened there is no need to do anything like mixing it with a new bottle. The enemy of glow fuel is moisture. If the bottle is never opened it has no chance to accumulate any moisture. As Gray Beard stated above, even opened bottles will last for a long time if the bottles are kept tightly sealed and only opened to pour out fuel. I've had a bottle of fuel on the shelf for over 5 years and when opened and put in a plane it ran like a brand new bottle of fuel. As stated many times, the key is keeping sealed.

Ken

As stated, store it right and good to go, I have 6 gallons right now that is at least 5 years old. It is inside and in the dark and just like I purchased it. If you want to see it you fuel has water in it let it freeze, guess what, the water will rapidly show! Actually a small amount of water seems ok if you shake up the fuel, jet liners use agitators to keep jet fuel and water mixed to get a clean burn, it like glow fuel will become water laden if exposed. Diesel fuel behaves much the same........

I have had fuel that was around 15 years old, it had been opened but put inside a closed cabinet in a garage all that time, it was just fine. The garage was unheated and it was in the central valley of Calif. The fuel was in clear plastic jugs. I just didn't see a lot of daylight over the years. My own fuel I buy is in cans, light has no effect on it at all. It's in a cool dry place, my shop. My shop runs from 100 degrees in the summer to 30 degrees in the winter and all points in between. People in other parts of the country may have problems with condensation but if kept in a dry environment there shouldn't be any problem. How you store your fuel is the key. Even storing my fuel in an unheated shop when I lived in the mountains created no problem. My unheated shop there was nice and dry. One good way to test your fuel is to put in in a plane and fire it up and run it. If you have moisture in your fuel your engine isn't going to run. If it fires up and runs then you have no problem. Other then moisture the nitro, oil and alcohol isn't going to go bad over time. It either works or it doesn't.

Yea - and Gene, where you live the locals consider 10% humidity to be uncomfortably damp. In CO we rarely get above 50% - mostly in the teens.

Sea, there is a bit more moisture in the Yosemite area, I lived up there for 21 years. Here it is about 6% in the summer and it has been about 25% or higher this winter here in Vegas. My friends in the mid west and east coast can see the humidity so I know there is a lot of difference. Dry place is a key word.
Did you read my post in kit building about the MAN article?? I found the one on the SU-29.

Well.........It's still Cool Power.

I sometimes use old fuel for break-in on the bench as long as it is clean it really can do no harm.

I think evaporation of methanol from opened fuel is more important than absorbed moisture. I think if you put out an open container of fuel sitting on a scale, that it would lose weight as the methanol evaporates rather than gain weight as water is absorbed. Maybe someone with a good scale will give it a try.

I think that would be an interesting test, but the results would depend on where you did the test (humidity of some areas are 100% while others are 5%), plus the level of ventilation of the room (partial pressures of methanol vapor may affect the results).

With a good triple beam balance, couple chunks of ice, and water, you can tell the temperature of your freezer without a thermometer.

Having lived in Houston for 7 years "any place else" is relatively dry. No Ididn't. see your post. I'll go check it out.

Found the thread. I will lurk with interest.

Since I have the opportunity to fix my LT-40 - gonna use it as a test bed for sheeting, fiberglass and sanding sealer / talcum power ...

I accidentally did a test. I left about a pint of fuel in an open container in the garage for month or more. When I realized what I had done, I checked and the only thing left was the oil. All the alcohol and nitro had evaporated away.

It will do that.

Flew with the fuel this morning and didn't have any issues (at least no issues with the fuel). Saito .82 fired up nicely, but I had some low-end issues. Which I will start a new thread about now......[link=http://www.rcuniverse.com/forum/m_10333534/anchors_10333534/mpage_1/key_/anchor/tm.htm#10333534]Saito Low End issues[/link]

I fixed a fuel issue with my tank and used the above-mentioned bottle of fuel and it ran nicely. I even accidentally left a full tank of fuel in the plane over night exposing it to even more air and it fired up first try. My issue was a busted fuel line, but 2year old + fuel seems to be ok.