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Time to find an ether substitute?

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Time to find an ether substitute?

Old 08-21-2005, 08:57 PM
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Mavi91
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Default Time to find an ether substitute?

It dawned on me the other day that, since my RJL converted OS .40 FP is pefectly happy using 20W50 instead of castor, that half the reason for using ether has gone away. I don't need to worry about disolving castor into the kerosene. The other half of the reason remains, of course, and that is lowering the ignition point of the kerosene. Surely, diethyl ether isn't the only light distillate that can do this. Obviously, things like benzene and carbon-tetrachloride would be way too dangerous even if you could buy them. But what about stuff like acetone, toluene or naptha? I'm not about to start playing mad scientist on my own with this stuff, but, is there a chemist in the house?

Oh, and yes, I know how wonderful castor is, etc. etc. But it costs a fortune and provides protection that I don't need if I avoid overcompressing or otherwise stressing/overheating my engine. Besides that, I'm guessing that a good quality 20w50 will tend to bind up combustion acids better than castor does.




Old 08-22-2005, 06:15 AM
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Default RE: Time to find an ether substitute?

Mavi91,

It would be nice to eliminate the costly (and sometimes scarce) ingredients, but your FP may not be quite as "perfectly happy" as you think.

It may be a good trade off though, if early parts replacement is greatly offset by the cheaper ingredients.

Good luck with your quest.

George
Old 08-22-2005, 10:20 AM
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Default RE: Time to find an ether substitute?

George,

Only time will tell, and I'll be happy to report any problems, but I'm betting on advice from people who claim to have been using "motor" oil in place of castor for years.

Castor's big claim to fame seems to be that it retains its viscosity and film strength as temperature increases. This property doesn't come into much play in a properly adjusted small diesel because of the greatly reduced operating temperatures. I found a performance comparison chart on the internet showing that castor does indeed perform as claimed. . .and is superior to even synthetic "motor" oils at high temperatures. However, for an engine that produces temperatures at the head/cylinder junction not much in excess of 220F, there doesn't seem to be any advantage to running castor. At the low end of the operating temperature range, the curves for castor and similar viscosity petrolium oils are essentially identical. If you try to operate a model diesel engine at the temps where the castor advantage kicks in, you're about to have larger scale problems that castor won't solve.

Since my FP wasn't designed for diesel, it might fail, but I'm betting that if it does it will be as a result of bending the con rod or snapping off the crank pin. . .I don't expect to see any galling of the bearing surfaces or cylinder wall damage unless I have a senior moment and run it overcompressed. To tell the truth, I wouldn't be as boldly experimental if I were running a $200+ USD purpose-made .40 diesel. But at the level of fuel consumption and the basic cost of a .40 sized plain bearing conversion head engine, the 9:1 price differential between castor and a name brand 20W50 in quart quantities and the 2:1 price differential (including shipping) between commercial fuel and my homebrew will more than pay for any wear or damage if I'm wrong about my lube.

Now, if I could find a consistent and predictable replacement for ether (*!@#! druggies), which was the original intent of this post, I'd really be in hog heaven. The starting fluid alternative seems to work, but now I notice court cases where they're getting convictions on meth labs based on the presence of empty John Deere starting fluid cans. So how long will it be before the manufacturers dumb down the ether content or simply stop making the stuff is anyone's guess.

Are there alternatives to ether? Xylene? Ethyl Acetate? Is anyone up on their chemistry? As a safety note here, I'm NOT advocating that anyone simply go out to their garage and try this stuff!


Old 08-23-2005, 12:21 AM
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Default RE: Time to find an ether substitute?

I doubt there's any substitute for ether because a lot of people have spent a lot of time experimenting with diesels, and I mean people heavily into world class competitions. The ether doesn't lower the ignition point of the kero but because ether has a flash point of -40 it ignites rather easily and this is where the flame comes from to ignite the kero.

One of the additives sometimes used in diesel fuel is Iso Propyl Nitrate (IPN) instead of amyl nitrate (or nitrite) and I know for a fact that a diesel will run on pure IPN because I tried a few drops in an old Mills 1.3 long ago just to see what would happen. It started first flick and ran out those drops quite nicely but I wouldn't suggest trying to make a fuel out of it even if you could find any.
Old 08-23-2005, 09:45 PM
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Default RE: Time to find an ether substitute?

I suspect you are correct, but I'm still curious to see if anything comes close to ether. I've been able to find tables with characteristics of various light distillates. Is flash point the correct datum to use for comparison?

While searching for the tables I ran across a report that says that over 450,000 kg of ether is produced every year in the US. Ignoring "controlled substance issues," my guess is that I wouldn't have a bit of trouble buying it if I was willing to order it by the barrel. I know firsthand that this is true for castor. I found a supplier locally who had a price of USD $1.67 per pound (.45 kg) for AA castor. All I had to do was order 440 pounds (198kg)!

So, all I need to do is either find 200 diesel flying friends to split the costs or figure out some alternatives.
Old 08-24-2005, 07:34 AM
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Default RE: Time to find an ether substitute?


ORIGINAL: Mavi91
So, all I need to do is either find 200 diesel flying friends to split the costs or figure out some alternatives.
SIG sells it by the gallon.

At one time you could buy it in 5 gal. cans from "Old Rhinebeck Aerodrome". Don't know if they still sell it but it is used as a lube for their full-size WW1 biplanes.

George
Old 08-24-2005, 09:31 AM
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Default RE: Time to find an ether substitute?

Thanks, I'm aware of the Sig castor. No reflection on Sig, as I'm sure they're offering it at the best price they can afford. . .but it is very expensive relative to what AA castor actually costs in bulk, which is my point. When just a few buyers have to bear the cost of packaging and marketing, the price goes up. In the meantime, Shell 20W50 seems to be doing a fine job in my homebrew at the cost of $1.59 a quart. I do take extra care to flush my engine due to the corrosion potential of the MEPK I'm using as ignition enhancer, but I have a suspicion that the 20W50's additives are trapping a good part of the combustion by-product acids and spitting them out along with the rest of the grime. The engine's innards look amazingly clean.

Having said all of that, I'm going to see if the 5 gallon cans of castor are around. There may be a cost benefit when the stuff is packaged this way.

From my locale, the price point for homebrew is the lube, not the ether. Eleven cans of starting fluid amount to roughly 1 gallon. . .at $2.00 a can. Even if I could get someone to sell me a gallon of ether, it won't be for $22.00!

Casual readers should take note here: I'm going on the reports of people who claim that they have run the kind of fuel setup I'm using. Your results, and mine for all I know, may vary. My advice is to buy commercial fuel if you're not up to a little adventure. I do promise to report here if my engine hurls chunks or the cat goes blind.
Old 08-27-2005, 11:12 PM
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Default RE: Time to find an ether substitute?

I think there are a few things that would work in place of ether, but none of the solvents mentioned so far. Problem is that they are either a gas, or even more expensive and rare than ether.
Old 08-30-2005, 09:12 AM
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Mavi91
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Default RE: Time to find an ether substitute?

That seems to be the most common response I get to my question, but I'd still like to know which of the many characteristics of a light distillate compound are the ones that one uses in making a comparison to diethyl ether?

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