TampaRC

I have always been confused on mixing my own fuel. By weight, by volume, liquid oz, etc etc,

In very plain terms, as in ounces of each product, lets say I want to create 1 gallon of fuel with 20% oil content. How many ounces of methanol are needed and how many ounces of oil are needed?

Is it as simple as 128 X .20 = 25.6? So 25.6 oz of oil and 102.4 oz of methanol? And then what if you want to add nitomethane ?

scale only 4 me

My Feedback: (158)

Same,, say 15% nitro,, add 128 x .15 = 19.2

So

19.2 oz nitro
25.6 oz oil
83.2 oz methanol

x% is always out of total gallon or 128oz

1QwkSport2.5r

Mixing by volume is easiest, mixing by weight is more accurate.

Always determine your oil % and nitro % first, then determine the remainder for methanol. I suggest adding the three chemical amounts to ensure you're getting 128 even. Converting to mL is easier than using fluid ounce measurements too.

badger5964

My Feedback: (6)

I mix my own fuel, no nitro. I believe in simple. I take one quart of oil, dump it in my mix container and add a gallon of methanol as measured using an old fuel container. I shake it up, add a couple drops of original Amour All (a simple defoamer), shake it up again (I like to see the foam reduction), fill up my field container and the rest remains in the old fuel container.

This make 20% oil. Some times I add a 10-16extra ounces of methanol to the mix to approach 18 %. Most commercial fuels today use 17-18% oil. I use Klotz super techniplate.

Why the obsession with making exactly a gallon?

1QwkSport2.5r

Got a jug that holds more than exactly a gallon? I don't. I use old fuel jugs (1 US gallon) myself. I'd find it rather a PITA to try to mix 5 quarts of fuel using 4 quart jugs. Maybe it's just me. Now I'm not saying you HAVE to mix exactly a gallon; adding your amounts of the chemicals added just ensures you added/multiplied correctly. I'd be a real SOB if you under measured the oil or over measured the methanol.

My 1gal fuel jugs fit my field box perfectly. The only fuel jugs I leave at home are the fuel mixes that are for engines I'm not run ing that day. I have 4 different jugs to use from depending on the engine. I use all castor in most of my brew - way cheaper than using klotz. I use some techniplate in my RC car fuel though - helps to get more rpm from the engines.

Altered1

I just cant resist: convert to metric, it all becomes so much simpler! Use a 1 liter jug - 800ml methanol, 200ml Oil for 20% FAI fuel

1QwkSport2.5r

Everyone in the US (or most everyone it seems) runs OS or Saito engines and therefore need to run a bunch of nitro in the fuel. Now if only everyone were smart and bought Enyas. LoL.

Mixed glow fuel is a couple pounds heavier than water per gallon, so mixing by weight is pretty easy too. Step one: add methanol. Stop pouring when xxxx Grams shows on the scales screen. Next add the oil until you get xxxx Grams on be screen. Add nitro until the final jug weight is achieved and cap/shake the mix.

Mixing by volume nets the user 5-7% higher nitro content, and 2-3% higher oil content. For cheapskates like me, that little bit saves me $$.

scale only 4 me

My Feedback: (158)

Ok, I'll bite.

So you say mixing by weight is how the fuel manufactures are doing it? or do they mix by volume?.

Been this hobby coming up on 40 years, run 2 stroke lawn equipment, Motorcycles, etc. etc. and never heard of mixing by weight until this thread.

1QwkSport2.5r

Most fuel manufacturers mix by volume. It's easier. Mixing by weight is more accurate. 15% nitro is 1.138g/ml. 15% by volume of a gallon is 567.811ml. 15% by weight is 495.60 using 3760 grams for a gallon. That's a 13% difference based on my calculations.

JPMacG

My Feedback: (2)

Why is mixing by weight more accurate? I understand that volume is temperature dependent (coefficient of thermal expansion), but that is a very small inaccuracy. Is there another source of inaccuracy?

topspin

This is the only company I know who sells Nitromethane in small (1 Gallon ) quantities. http://klotznitromethane.com/

There are racing suppliers but I think they have large minimums.

So if you can get it shipped here to the States, mixing is simple but keep in mind that Nitromethane is corrosive and you don't want it on your skin.

Just mix 25 percent Nitromethane by volume with Methanol. One US Gallon equals 128 fluid ounces so for 25 percent nitro mix 96 ounces of Methanol with 32 ounces of Nitromethane. Then mix 12.8 ounces of Castor or synthetic oil and you have just a little over one gallon of 10 percent glow fuel.


OR, YOU CAN BUY IT ALREADY MIXED........

topspin

larry@coyotenet

My Feedback: (21)

It's simple, oil weighs more than alcohol. Mixing by weight means using less oil but still having the ability to claim a certain percentage of oil or for that matter nitro.
The oil and nitro are the expensive parts. As for how to mix fuel, it's simple ratios, I just use any convenient container, like a drinking glass for instance, and mix lets say 1 glass of nitro. 2 glasses of oil and 7 glasses of alcohol and end up with 10% nitro, 20% oil fuel. Just keep doing this until you get whatever amount you need. Simple.
Larry

RC_Fanatic

My Feedback: (1)

Amazon sells gallons of 100% nitromethane at $51.25 with free shipping.
http://www.amazon.com/Torco-RC-100%2...s=nitromethane

GREG DOE

Larry, I agree with keeping it simple. I use a fifth (1/5) whisky bottle. Put marks on it for 1/4, 1/2, 3/4 and full. Fill it full for 20% oil. Three quarters full for 15% nitro. You get the idea? Good luck, Greg

1QwkSport2.5r

The reason I went over to mixing by weight was for a few reasons. One I found by happenstance; I have several European engines that have high compression and will not tolerate a lot of nitro. Mixing my nitro by volume didn't agree with a couple of my engines. 5% was more like 8-10% and they deadsticked often. Mixing 5% by weight works much better and the engines run well on it. Being that the oil is close to 1g/mL, this component is often the closest to being equal in weight and volume.

Methanol is .791g/mL, castor is .97 g/mL, nitromethane is 1.138 g/mL, and I estimate Klotz techniplate at .92 g/mL. I have not found a definitive weight for the klotz oil yet.

Altered1

Ok, so does this mean that fuel manufacturers should state on their packaging if the fuel is say 20% oil by weight or 20% by volume ? 

If I was after the most profits, i'd mix by weight, and keep quiet on the actual ratio.

So theoretically the fuel should be sold by weight if mixed by weight, and sold by volume if mixed by volume?   1 Kilo or 1 liter.

bjr_93tz

99% of engine instructions and values shown on premixed fuel will be expressed by volume, ie. 1 litre of 10% nitro 20% oil 70% methanol will (should) contain 100cc nitro, 200cc oil and 700cc of methanol.

Personally I mix by weight AFTER converting volumes to weight using the density of each component. Nitro weights 1.14kg/litre, Coolpower blue 0.98 kg/litre, castor 0.96kg/litre and methanol 0.79kg/litre.

This allows me to grab however much of whatever mix I last used and convert it to however much I want of whatever ratio I need for a different motor with just a set of scales. My digital scales read in grams so +_ a couple of grams is much closer than just above or just below some line on my 1 US gallon mixing bottle.

An example would be my fuel mix for my .10FSR One litre of 15% nitro 25% castor 60% methanol = 150cc/250cc/600cc or 171g/240g/475g

drac1

My Feedback: (4)

As nitro is approximately 1.375 times heavier than methanol and the oil weight is different again, it is much easier to mix by volume. As far as i am aware, most manufacturers mixing ratio recommendations will be by volume.
I have been flying for 18 years and i fly 2 strokes, high performance four strokes and gas engines. I fly competitively in pattern and have always mixed my own fuel. I've never had a problem due to fuel mixes.

scale only 4 me

My Feedback: (158)

So
First in order to determine accurate weight per ounce, you have to have an accurate system to determine volume,, if you have an accurate system to determine volume, there is no need to convert into weight. Just not sure what I'm missing here.

bjr_93tz

Maybe, until I want to turn whats left in my DZ170cdi bottle into something for my .75AX, Hanno .61, or .10FSR

I just made up a spreadsheet with mixing values for different volumes for my different engines and my casio calculator handles the oddball "turn this fuel into that" equations. It'd be almost just as easy by volume but I hate cleaning out my 500ml graduated cylinder which now is used for storing odd lengths of carbon rod and piano wire


Two ways to skin the cat and neither are wrong if the end results are percentages by volume.

1QwkSport2.5r

I should have clarified - this is how I measure. All volumes are converted to weight.
A graduated cylinder or beaker work fantastic for accurately measuring liquids. Liquid measuring cups work good too. But... I don't think you understand the whole idea. The idea is to have the accurate amount of a given substance. Volume does not get accurate enough. Premixed fuel (by volume) will have "extra" nitro and be short on oil slightly. For the *most* part, this doesn't matter but to me it does because some of my engines are quite picky.

drac1

My Feedback: (4)

You are correct. If you need to measure out the volume and then weigh it, you are making twice the work.
Weights can be obtained from the manufacturer of the methanol, nitro and oil, so no need to measure and weigh.

Google is your friend.

drac1

My Feedback: (4)

Why would you want to turn your cdi fuel into something else? It would be easier to mix a different mix for the other engines.

I keep it simple by only using two mixes. One for my 170/175 cdi's and one for everything else.

The only time i have had to alter a mix, is when i changed oil content part way into a bottle. Just measured what fuel is left and calculated the amount of methanol, nitro or oil required to obtain the mix i wanted.

scale only 4 me

My Feedback: (158)

No, I understand the idea, some guys just want to over analyze and over complicate a simple process.