1QwkSport2.5r

Disclaimer: This can be a DANGEROUS process. Do your fuel mixing OUTSIDE of your home!! Alcohol fires are very hard to see and can spread quickly. Have a fire extinguisher handy just in case. I am not responsible for burning you or your home/garage down!

Again, This stuff is dangerous and flammable. Use common sense, be safe, and be CAREFUL!
You will need:
100% Pure Nitromethane
Castor oil
A quality Synthetic oil like Klotz or SPL Lubricating oil.
100% Pure Methanol
Optional - Armorall Original
A suitable container to hold your mixed fuel. I like using empty metal cans that Acetone or Denatured alcohol comes in as light cannot get in. Plastic gallon or quart fuel jugs/bottles work fine as well.
A measuring vessel of some kind. A graduated cylinder, liquid measuring cup (dont use for cooking/food after making fuel with it!), or Graduated fuel bottle.


I use a drop of Armorall per quart when I'm ready to use the fuel to act as a defoamer/debubbler. Cars bounce a lot and it will send bubbles through the fuel line leaning the fuel mixture. This is optional, but I find fuel mixture stays more consistent if you use a little. Some people say Armorall will kill glow plugs, but I rarely blow glow plugs. Some plugs have more than a gallon or two of my homebrew on them and they run fine.

First step: Decide what content of each ingredient you want; ie: Oil content and Nitro content. Typically, for a basher, I use 12% oil and 20% nitro.

Second step: Decide how much fuel you want to mix at a time. I prefer to mix a quart at a time since I don't burn a gallon at a time. This helps keep the fuel as fresh as possible.

Third step: If mixing a quart at a time, using your content percentage, multiply it by 32. 12% Oil = .12 x 32 = 3.84 fluid ounces 20% Nitro = .20 x 32 = 6.4 fluid ounces. You can either multiply .68 x 32 to get 21.76 fluid ounces of Methanol, or you can subtract 10.24 from 32. Either way works. Now, for ease and accuracy, I convert Fluid Ounces to Milliliters as the fractional amounts are easier to measure. If you want to use all synthetic or all castor in your fuel, you dont have to split the volume of oil. If using a blend of oils, use what blend percentage you want to use and multiply it by the total oil amount (in the example below, 3.84oz or 113.5mL). Typically, car fuel is either an 80/20 or 70/30 blend of synthetic/castor oils.

So, in this example, we need 3.84oz (113.5mL) Oil, 6.4oz [189.3mL) Nitro, and 21.76oz (643.5mL) Methanol. This totals 946.3mL which is 31.9oz mixed fuel. If using an oil blend as discussed above, say 80/20, then multiply .80 x 3.84oz (113.5mL) to get 3.072oz (90.8mL). Subtract the total oil content by 3.072 (90.8mL) or multiply .20 x 3.84 to get .768oz (22.7mL). 3.072 + .768 = 3.84oz. A 70/30 blend is determined the same, but the numbers are different obviously. 2.688oz (79.5mL) + 1.152oz (34.07mL). I round to the nearest tenth of an ounce, but if you really want to get nitpicky and get down to the thousandth of an ounce, more power to you. Its not necessary as your engine isnt going to notice .010oz difference in a given amount of something.

Fourth step: I measure my fuel ingredients with a 500mL fuel bottle. Since the methanol content is almost always more than 500mL, I fill the bottle once, and dump it into a jug. The remaining methanol is measured in the graduated fuel bottle, and I add the oil and nitromethane to it and shake it up. This makes it easier to get most of the oil mixed and out of the measuring bottle. If you so choose, you can dump the remaining methanol/oil/nitro mix into the storage vessel and dump a little of the mixture from the big jug into the mixing vessel and swish around to get most of the methanol/oil/nitro mix out. Dump the measuring bottle back into the storage jug and give it a good shake. Cap off and you're ready to use it.

It sounds like its complicated, but its easy as can be. I suggest writing down the various ingredient amounts on a small notepad and have it nearby to glance at it to double check your amounts. Its easy to loose your place and use too much or not enough of something and end up with something that can ruin your engine. Measure and double measure everything to be sure its accurate.

The hardest part of finding the ingredients you need will be Methanol. Find a local oil company or Auto race track/dragstrip. This is where you are most likely to find it. Getting it shipped can be expensive, so try to search locally. Nitromethane can be sourced from several places, but my two suppliers are either Torco Race Fuels or FHS Oil Supply. I order Castor oil and Klotz techniplate (full synthetic) from SIG Manufacturing as I get other model materials from them at the same time to combine shipping. SPL Lubes and Tommy's Karts are two other oil suppliers.

Methanol should be around $2.50 per gallon. A good plastic Diesel or Water can (yellow or blue) works fine. Windshield Washer jugs work fine as well. Mark your jugs/cans/bottles with its contents!!! Methanol is clear and POISONOUS. It is clear and has little smell. It will cause BLINDNESS if ingested!
Nitromethane is $50-$60 a gallon
Castor is $12-$24 a gallon typically

Keep these chemicals LOCKED UP or put somewhere where KIDS can't get into them. They can cause serious illness or death!
Startup cost is high, but the per-gallon price is much much less than a jug off the LHS shelf. I can burn 2-4 gallons a year for the price of 1-2 gallons from the LHS. Its a no-brainer for me.

Source websites:
Nitro:
Torco Race Fuels - www.torco.com
FHS Supply - www.fhsoils.com

Methanol (local to me)
Lubrication technologies - www.lubetech.com
Wilson Oil Company - www.wilsonoilcompany.com

Oil:
SIG Manufacturing - www.sigmfg.com
SPL Lubes - www.splube.com
Tommy's Karts - www.tommyskarts.com
Klotz - www.klotzlube.com

If there are other suppliers/distributors you find or you have questions, post a message in this thread or PM me.

Mixing by volume is the very common method for making fuel, although you can mix by weight. I do not mix by weight, and don't feel it necessary to discuss it as it is not what the leading fuel manufacturers use. Mixing by volume will give a slightly higher percentage by weight of nitromethane, a lower percentage of methanol by weight and slightly lower percentage by weight of castor oil. Again, mixing by weight gets complicated and really unnecessary IMHO. Here's the weights of the three main components for those that care:

Nitromethane weight : 1.1382g/mL at 68°F, and 1.1244g/mL at 86°F
Methanol weight : .79g/mL
Castor oil weight: .969g/mL.

Volume measurement conversions:
29.5735 mL = 1 Fluid Ounce
3.78541 L = 1 US Gallon
Weight measurement conversions:
0.035274 grams = 1 ounce
0.453592 kilograms = 1 pound

Good luck and happy modeling.

Again...This process is not for the inexperienced modeler, young people, it is NOT to be done in your house or garage, and is not for everyone. I am NOT.. I repeat NOT responsible for your indiscretions while making fuel or handling its ingredients. HAVE A FIRE EXTINGUISHER NEARBY!

Anthoop

Good guide, thank you. I must admit I got a little lost with all the weights/measures in the middle, I am confused as to why you convert numbers...why not mix one litre of fuel with (percentage wise), x ml of meth..etc. If you want more litres of fuel then just multiply the numbers.
I am glad you mentioned weight at the end...electronic scales are fairly cheap these days though...

1QwkSport2.5r

Well, the jugs I use are in gallon jugs, and if mixing 4 litres of fuel, it wont fit a gallon jug. 4L = 135.68fl oz. Also, getting .6oz or .3oz is much easier to measure in mL than Fl. Oz. True, scales are cheap, but not all of the components weigh the same and require more math than I feel is necessary. Also, you cannot measure the weights of each individual element in a mixed product. You would still have to measure out each component separately, and also getting that exact really isnt necessary IMHO.

I did figure out at one point the weight per volume of each of the components I use except the Klotz synthetic lube. I figured the weights using some math and figured it to grams per milliliter. I added the weights of Nitro, Methanol, and Castor to my first post.


I'm still trying to find the weight of Klotz Techniplate since thats what I use, and I'm only posting the weights for reference anyway. I'm not going to track down every weight of every kind of model engine oil out there, because I really feel its not necessary to know or the method to use.

downunder

SG (Specific Gravity or density) of [link=http://www.rcfuelsupplies.com.au/index.php?_a=viewDoc&docId=9]KT[/link] is 1.002 so call it the same as water.

Mixing your own fuel is about as easy as mixing 2 stroke fuel for a lawnmower or chainsaw. I should point out though that care has to be taken to mix only by volume and not by weight when terms like ounces are mentioned. This may seem obvious to Americans but is very confusing for non-Americans who don't use fluid ounces as a measure of volume. With a bare minimum of common sense it's quite safe to mix your own fuels. Basically, do it outside and don't smoke or drink the ingredients while mixing (same as when mixing lawnmower fuel). You can drink some castor if you want but only if you're constipated . Methanol is extremely poisonous so don't try syphoning out of a container by sucking on a hose as if you're stealing petrol from a car.

Using the metric system also makes things so easy it's almost laughable. For instance, if you want a litre of fuel (a fraction more than a quart) with 17.5% oil, 18% nitro and 64.5% methanol then just multiply each % by 10 to get...
175cc of oil
180cc of nitro
645cc of methanol

The only time you'd need a calculator, or pencil and paper, for this would be if you wanted a blend of castor/synthetic oils so if you wanted an 80/20 blend of the above total oil then just multiply the 175 by .8 for the volume of synthetic then by .2 for the castor.
Shake well and serve to the engine .

Anthoop

I agree mixing by weight is not really necessary, but I am pedantic and (more to the point) I could have access to scales that would be perfect for mixing up to five litres of fuel. Once you have a formulation for the required weights for one litre of fuel, then it is simple to multiply the numbers or even zero the scales after mixing a litre.

I guess it is what you are taught that make the most sense?