pilotpete2

Hi,
A question for the fuel experts!
I have a gallon of 15% Nitro S&W Heli mix that has had white crystalline salts settle on the bottom of the jug. The fuel was stored in the cellar, in the dark and stable temperatures. The bottle was new and never opened. Any thoughts?, other than dumping it?
Pete

earlwb

I would shake it up good and see if it mixes back in. Then try a tank and see what happens. I don't think there is anything wrong with it. Some glow fuels may have some settling if the fuel sits for a long time. it is some of the substances settling out. usually stirring or shaking the fuel mixes it back in OK. If it was sealed OK and not breathing where it would suck air in and out, then it should be good to go. I have some glow fuel that is over 20 years old that still works fine. But if the container wasn't quite sealed perfectly, it might let vapor pressure out when hot and suck air in when cold. The air of course has moisture in it and the methanol tends to absorb the moisture. Also a fellow in Australia did some water tests with glow fuel and found that it still works Ok even if it has absorbed some water into it. But eventually too much of a thing will affect it though.

1QwkSport2.5r

Does the substance look similar to the picture I attached?

pilotpete2

Yes, it sure does!
I did try shaking it, but it didn't seem to dissolve any of the crystals, they just settle out again. The size of the crystals is very similar to the coarse salt they use on soft pretzels.
I'll give it a go later this week. At the moment, I only have one glow powered model flying. All my other planes are either gas or electric.
Pete

1QwkSport2.5r

The picture I posted is 80/20 FAI fuel (castor oil only, no synthetic) that's been in the freezer for awhile. The castor settles out when it gets cold. If your jug of fuel is sealed still, try putting the jug of fuel in a tub of warm water for awhile and see if the globules re-dissolve. Give the jug a shake afterwards. If they don't mix back in, I'd filter the jug using a coffee filter and maybe add an ounce or two of oil and run it. Sealed fuel is good for many many years if kept in a controlled environment.

earlwb

Good point. I just noticed that the OP is in Vermont and I assume it gets a bit chilly up there. When cold the castor oil can settle out. What 1Qwk stated about warming up the jug of fuel ought to do the trick.

drac1

My Feedback: (4)

Fuel doesn't go off - It gets contaminated.

I've had fuel stored for years and still works fine.

1QwkSport2.5r

How does a sealed/unopened jug of fuel get contaminated?

phatbob02

My Feedback: (126)

Me .......I won't risk using it. Two years ago I had a bad summer with every nitro I owned. I had a brand new case of a popular 15%. Engines won't tune, flame outs in flight, I was pulling my hair out. A club member mentions that a lot of guys were having probs with the brand. Changed to VP 20/20, cost more but the best stuff I've ever used and no more problem.

RCPAUL

My Feedback: (1)

If you take the jug outside where it is warm and the substance disappears, it is ok. If it doesn't, the castor has probably gone rancid. I've only had this happen once. Clarence Lee commented on this many years ago. Rancid castor will varnish the engine and cannot be filtered out.

drac1

My Feedback: (4)

I didn't say an sealed/unopened jug gets contaminated. I said fuel doesn't go off, it gets contaminated.

1QwkSport2.5r

The only reason I ask is the OP has a sealed/unopened jug that has white globules on the bottom. Just curious if it's indeed oil that settled out for some reason or if there's another substance in the fuel that would do such a thing. I doubt the fuel is bad per sé, but perhaps the temperature which it was stored at may have contributed to the phenomena they are witnessing.

pilotpete2

Hey folks,
The unopened jug never saw temps below the mid 60's, I have heat in the basement.
The precipitate is a hard white crystalline material (about 2 Tsp. worth) that much heavier than the fuel itself. If you shake the jug, it settles out very fast. The fuel is the same appearance of the good gallon I'm currently running, and smells identical.
I plan on fling on Wednesday, So I'll try a tank and see how the engine runs.
I have no knowledge of chemistry, so I was wondering if it was related to the Nitro-methane. I can't imagine it being from the Methanol or synthetic lube.
If it runs good on the ground, then I'll give it a a test in the air. The plane is a floater, I won't worry too much about a deadstick.
Currently only own two glow engines, both 4 strokes. The nearest hobby shops is in Canada. I wouldn't even want to think about bringing glow fuel across the border
For my gassers, we have a Valero station 1/2 mile from the flying field, and their 93 Octane is Ethanol free...I like gas
Pete

Earl,
It does actually get warm up here in the north country. It's those blasted Canuks that keep sending down the cold air
But eh, they're good folks, we even have them as members of our club!

drac1

My Feedback: (4)

I store mixed fuel with 30% nitro and have never had any problems like you're experiencing. I don't do anything special, just make sure the lids are tight and sealed. I keep the raw ingredients in steel drums and /or plastic bottles and in plastic bottles once mixed.
I keep everything in my garage and the temperature varies from below 0 degrees C to 35 degrees C.


Steel containers can rust etc inside and cause problems. Plastic bottles can also get moisture inside. Not sure whether it's condensation or if it's absorbed through the plastic. I've heard theories for both.

JPMacG

My Feedback: (2)

Interesting thread. I use a lot of S&W fuel myself and have never seen this. I think the S&W Heli mix has no castor content.

I wonder about the nitromethane. I think the nitro used by US fuel manufacturers is imported. Quality control in Asia may not be so good.

drac1

My Feedback: (4)

I have also used castor in the past with no problems like the OP has.
Quality of nitro maybe an issue??

1QwkSport2.5r

I wonder what they use for wetting agents or defoaming agents of any... When I used to use armorall for a defoaming agent, I noticed the armorall would fall to the bottom after a few months though it wasn't a hard substance like sand. It was soft like the castor globules I pictured several posts back.

I doubt this phenomena is related to the nitro, methanol, or oil directly. I suspect there's another substance in that fuel that fell out of suspension for one reason or another.

earlwb

I am now also suspecting it is some substance or additive that has settled out of the fuel. It could have also been one of the last fuel jugs at the end of a production run and had the crud leftover in the main tank they were getting the fuel out of. I would suggest pouring the fuel into another container down to the last little bit at the bottom and stop. Then dispose of that bottom leftover amount with the crystals in it. The fuel should still be perfectly fine to use.

flysti06

blw

My Feedback: (3)

India is also a big exporter of nitro.

Something was touched upon, and that's plastic jugs. There's been some instances where members kept getting bad fuel when they refilled their plastic jugs. Whatever happens to ruin a jug of fuel will get into the plastic and leech into the fresh fuel when it is poured in. So, if the fuel is bad so is the plastic container in some cases.

Bax

My Feedback: (11)

It used to be axiomatic that fuel would improve with age. That's from when the only lubricant was castor oil. What would happen was that some fat solids would precipitate out of the fuel and fall to the bottom of the jug, looking like cracker crumbs. A few warm/cool cycles caused it and the fuel would usually be fine when it warmed up. If the "crumbs" don't go back into solution when warmed up, then you have fuel with rancid castor oil that's only good for weed killer

This applies only to fuels with castor oil. If you have 100% synthetic oil with the solids coming out of the solution, then you have contaminated fuel.

pilotpete2

OK, I tested the fuel yesterday in one of my 4 stroke powered planes. No difference in starting or running was detectable. I'm just going to use it up.
Thanks to all for your interest and input!
Pete

blw

My Feedback: (3)

Bad fuel is good for killing ants too and it's a very good paint stripper.

1QwkSport2.5r

Nitromethane is a great solvent for dissolving CA glue too.

jeffie8696

I have heard of an additive used in glow fuel that can cause deposits to form, I believe it was added as a friction enhancer