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"Notes from the Unit Shop"

Kevin O'Connor's advice for the beginning small scale live steamer







Alcohol firing of small-scale live steam locomotive boilers is the oldest method of producing steam in such small mechanisms that is still in current use.  An earlier method of producing steam in builder’s and patent models involved heating a pig iron block red hot in a coal fire, and then placing the hot block in a “firebox” constructed in, or underneath, the model’s boiler.  The hot block radiated its heat through the boiler’s shell and into the water in the boiler.  Usually one block was enough to heat up the boiler to near the boiling point.  When the temperature of the block was slightly above the temperature of the water the first block was removed and then replaced with a second red hot iron block.  Now the model was ready to perform the work that it was intended to demonstrate.  Some early gauge three locomotives were “fired” in this way.


Alcohol firing of model locomotives of all gauges is most popular in England and its commonwealth nations. This is because of the long tradition of using alcohol-fueled wicks as a source of heat in model trains as far back as the end of the 19th Century. In the United States the early model train manufactures favored electric power to provide motivation, and so it is still rare to see small-scale (#1 & “O” gauge) live steam model locomotives here in the States.  You and I know of this facet of the hobby, but I am continuously surprised to meet long time model railroaders who have never even heard of live steam power running on 32 and 45-millimeter track.


This discussion of alcohol fuel will be limited to just that; alcohol as a fuel, and not a how-to about operating a model locomotive.  How-to information can be obtained by purchasing and reading the pamphlet “An Introduction to Alcohol Firing” by R. (Roger) Loxley. 




There are dozens of alcohol types produced by industry, but we will only deal with the two most common types in this discussion.  The first alcohol was produced eons ago by yeasts that fed on composting vegetable matter.  Early mankind entered the equation when it was discovered that the white coating on grapes was a yeast that when combined with the juice of the grape would transmogrify into a fermented beverage; if you could keep the vinegar flies out of it.  At some point it was discovered that grains like barley, wheat, and rice could also be fermented and so beer making was off to a start.  Honey was fermented into mead.  In some Muslim communities mead may be consumed by believers because it is not the product of fermenting grapes and grains wherein the prohibition lies.  Distillation was the next step.  In this process the fully fermented liquid is heated so that the alcohol in the mix boils off and passes through cooling coils where it condenses and collects at the end of the line.  In theory this distilled liquid is pure ethyl alcohol, known as grain alcohol, and is identified as 200 proof for federal tax purposes.  Alcohol intended for human consumption is generally cut in half, or more, with water although there are exceptions.


Alcohol can also be produced by a process called reduction.  In this process wood is heated in a sealed container without the presence of oxygen until the wood degrades into charcoal.  Many gasses are given off in this reduction process and they are cooled through a condensing coil.  One of the liquids collected is methyl alcohol; known as wood alcohol.  Methyl alcohol is 100% poisonous to human beings and its ingestion into the human body will cause rapid and complete destruction of the human liver and kidneys.




Both ethyl and methyl alcohols are clear and colorless liquids with similar physical and chemical characteristics.  Because of the poisonous nature of methyl alcohol its uses are mostly reserved in the service of industry as a solvent and as a vehicle for other products.  It is used as a fuel for recreational boat stoves as well as back-packer type stoves.  Shellac is made from synthetic gums that are dissolved in wood alcohol, and Sterno is a jellied form used in camping and professional food presentation.  Ethyl and methyl alcohols have different caloric values with ethyl being the larger at 12,550 BTU per pound and methyl at 10,200 BTU per pound.  Pure methyl alcohol has almost no detectable odor, while pure ethyl alcohol has a slightly attractive sweet odor.




There are as many “formulas” for denatured alcohol as there are manufacturers who provide it to consumers.  Periodically (here in the States anyway) the long arm of the law reaches out to the producers of denatured alcohol and requires them to alter their proprietary formulas.  When I first discovered the small-scale live steam locomotive hobby (1995) the denatured alcohol that I first used was Kleen-Strip’s version called S-L-X.  It was then, as now, available by the quart and gallon can in the paint department of Home Depot stores throughout the States at about US$8.00 and change per gallon.  In 1995 S-L-X was made up of nearly equal parts of both ethyl and methyl alcohol with less than 1% Methyl Isobutyl Ketone (MIK) added to keep the Alcohol, Tobacco, and Firearms (ATF) branch of the Department of the Treasury happy.  A couple of years ago (1998?) the ATF “asked” Kleen-Strip to alter their proprietary formula.  The result is that now S-L-X is composed of 80% methanol, less than 20% ethanol, and MIK not to exceed 3%. 


The other big producer of denatured alcohol in the states is Parks Corporation.  Parks markets denatured alcohol under their own name, and they manufacture it for resale under “house brands” for other retailers.  One such retailer is True Value Hardware.  I was not able to obtain the proportions of ethyl to methyl alcohol that Parks uses in their denatured products, but since the ATF is involved is probably safe to assume that the ratio is very close to the Kleen-Strip formula.  However, there is a heck of a difference in the additives that Parks inserts into their baseline denatured alcohol product.  First they start off with MIK, as does Kleen-Strip, but then they add Rubber Solvent (I am unable to identify just what that is) and less than 1% each of both Toluol and Benzene.  I am not a “tree hugger” and I do not have a problem with additives to products to improve their value or properties, but I do have a problem if these additives “seem” to affect the operation of our small scale live steamers; more on this subject in a later section .



(pure methanol, methylated spirits, “methys”)


Methyl alcohol is readily available in the states from local companies that cater to the “Hot Rod” and racing car market.  It costs around US$3.00 per gallon provided you bring your own can.  Many of these car’s engines operate using straight methyl alcohol as their fuel of choice.  Since gasoline (petrol), which is the fuel of choice for motorists, contains in excess of 20,000 BTUs per pound it requires far more pounds (gallons) of methanol to develop the same horsepower in any given internal combustion engine; especially if it is a highly modified engine designed to produce gobs of raw horsepower in the racing environment.  In order to produce this kind of power very large fuel lines (3/8” diameter or better) are used to transport the methanol from the fuel tank to the fuel system injectors. 


The reason most often given for the use of methanol over gasoline in these racing applications is that the critical temperatures (piston crown, intake and exhaust valves and seats, and head) are much lower per developed horsepower when operated using methanol as the fuel.  The key to this logic is that it takes many more pounds (mass) of methanol to produce the same horsepower, as does gasoline.  The conversion of this liquid fuel (mass) into a flammable vapor, and then introduced into the engine’s cylinders, efficiently cools the combustion chamber between power strokes.  The bottom line is that more methanol in pounds or gallons is consumed per unit of time versus the use of gasoline, but the engine’s critical temperatures are held in check and the engine’s useful life (though short by domestic use standards) is extended.




Ethyl alcohol is available from chemical and scientific supply retailers in the States.  There is some paperwork involved in its purchase and there is a hefty ATF distilled spirits tax to be paid (it used to be in the neighborhood of US$10.75/ gal.) plus the manufacturers and retailer’s markup and then the applicable state sales tax.  By the time all this is added up the cost of a gallon of 90% neat ethanol will hover around US$ 25 to 30 dollars; not much of a bargain.  100% pure ethanol is also available, but at a much higher price.




In 1995 I purchased my first alcohol-fired locomotive; it was an Aster B-1 Baldwin and it was not a good choice as a first alcohol fired locomotive.  Mechanically the locomotive was produced in two versions.  The first 1000 or so units used a four-cup wick burner that was traditionally mounted between the frames of the locomotive.  Suffice it to say that on this locomotive it was impossible to keep the front wick lit, and many examples wound up on the mantel or in pieces in an old shoe box.  The remaining 500 units were modified (I’M guessing at this number since conformation is not available) to include a stainless steel “belly pan” that completely enclosed all four wick-cups to protect them from the winds of passage.  I have never operated one of these Baldwin’s so modified, and so I have no feel for the effectiveness of the “fix”.  After I figured out my particular locomotive I wrote an article that was published in Steam in the Garden (SitG) to alert others that the locomotive could be made into a reliable locomotive.  I mention all this as I want to make it clear that the locomotive that I used to evaluate the three alcohol fuel products that I’m going to write about were all used in the same, well understood, model locomotive. 


As I said earlier my first alcohol fuel was the 50-50 version of S-L-X from the Home Depot store.  As it all turned out this fuel was a blessing to this tyro as it had no bad characteristics as it was chemically neutral to the copper wick-cups and the fiberglass and later “mystery materiel” wicks.  Once I had the Baldwin sorted out I fiddled with the wicks length and tightness (see the article in SitG) until I could achieve reliable (and boring!) running on my home (flat) track pulling four cosmetically modified Mammod vans.  The locomotive would run all day at 25 to 30 psig only stopping to be fueled and watered as needed. 


I operated the locomotive through 1997/1998 using the original, to me, fiberglass wicks.  During this period I learned about the unique care that fiberglass wicks require, and they were well attended to.  In the fall of 1997 I re-wicked the Baldwin with “mystery materiel”, a more traditional form of wicking, and then groomed the wicks until the locomotive behaved as before.  There are several things that I like about “mystery materiel”, but the biggest plus is that the tops of the wick strands do not melt and clot up as does fiberglass.  Care is still required to put the wicks out dead cold at the end of a run lest they sit and smolder and loose length over time.  Thus, armed with this fine running Baldwin B-1 bunkered locomotive, I departed for Diamondhead.





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