My LHS also does the lion proglow blended syn for about $10 a liter as well.
i'm thinking about going to a blended syn due to less mess what do ya think about this

75% meth, 5% nitro, 2% castor, 18% klotz any thoughts?
with this blend i'm thinking of dropping down to 18%
77/5/18(2/18) total oil any thoughts on that?

Gidday again men, I've worked out that I'm saving about $4.50 a liter by blending my own fuel, 77% methanol, 3% acetone, and 20% castor. I'd rather not purchase blended fuel due to the expence. I guess to be on the safe side and have a cleaner engine, I could add a little synthetic to the blend, maybe a 10% synthetic 10%castor. I'm happy with the performance using the acetone instead of nitromethane and it's cheaper too. My only concern is how my blend will effect engine life. From what i've gathered on this thread it won't be an issue. Thanks, John.

Does the acetone perform the same as the nitro? and why 3%? why not 5% (or more) like the nitro, for that matter why not 0% just a straight 20/80 blend

Originally posted by Woodsy
My LHS also does the lion proglow blended syn for about $10 a liter as well.

I just checked my costing, and it currently costs me approximately half that to blend my own 5% nitro all synthetic. I carried out a cursory check of retail blended fuel pricing when I intitially returned to R/C, went into sticker shock, and decided to blend my own as I always have. For myself, I would consider retail pre-blended fuel only with three provisos being met. (i)acceptable price differential, (ii) full range in availability of product, (iii) proven quality control. I think the latter has been achieved, but the former are sadly lagging, in Oz at least.

i'm thinking about going to a blended syn due to less mess what do ya think about this 75% meth, 5% nitro, 2% castor, 18% klotz any thoughts?

I typically run a very similar brew to what you've suggested for general sport & Sportsman pattern practice with my gammut of schnuerled TBR 40./.46 ABC, ABL, AAC types. (Enya CX 45AAC, OS 46FX ABL, OS 46SF AB(C)N, & ST S40K ABC. I get away adequately with a budget brew of just 5% nitro because I'm running those powerful oversquare two strokes designed to rev hard with smaller diameter props than a four stroke would ordinarily use.

Its proven that with competent tuning you can safely get away with less content running on all or nearly all synthetic. Nevertheless, I run 20% with those engines of which between 2 & 3% is castor depending upon the meniscus and my eyesight on the day. It's arguably more than actually required as a minimum, but I run the extra couple of percent as insurance. Given the price of a replacement genuine OS P&L for an 46FX in this country, an extra 2% synthetic + 2% castor is a relative bargain!

I use either Klotz or CoolPower, whichever happens to be available at the best price. I just finished my last batch of Klotz and am currently mixing with CoolPower. Similarly sometimes Castrol M, sometimes the Lion degummed stuff. I find needle setting is notably much more sensitive on that brew or a straight synthetic vs a 50:50 synthetic:castor blend. I've found it much less tolerent of a lean run, which is reflected in seemingly immediate demise of the glow plug should one err on the lean side. Like yourself, I really went to it because of the mess, and the disappearance of the significant former economic advantage of using a high base level of castor. Upon reflection, for beginners and low tech sport flyers not comfortable with competently tuning their engine, castor is a far safer and user friendly alternative despite the physical mess. Certainly for two stroke use. It's all we had once, and we managed.

with this blend i'm thinking of dropping down to 18%
77/5/18(2/18) total oil any thoughts on that?

Not sure of the total oil content you suggest here, but you can safely run 18% all synthetic in a two stroke in my personal experience and according to Powermaster's FAQs et al. Just take care to take the time to tune to avoid a lean run and discipline yourself to land if the engine goes abnormally lean in flight. Don't be tempted to continue the flight with it running that way. Throttle back, land and correct it immediately.

Hi Woodsy, Downunder gave me the info on acetone. Apparently it gives better idle and it also absorbes moisture from the methanol. Why only 3%, I don't know but perhaps the experts can enlighten us. Sigrun also has written a bit on it in his post on this thread. I've tried this brew and am happy with the results. It's also cheaper then nitromethane, only 6.90 for 1/2 a liter. There are some differing views on this thread but all the info has had some merit I think. Regards, John.

The addition of nitro will increase the cost, but a small percentage (between 5 & 10% is all you need) will make the engine idle better and the needle easier to set.

A 20% 50:50 synthetic castor blend works well. Probably the safest combo for the best of both worlds.

If you use sufficient oil of either type or a combo and tune correctly, you won't have a problem with P&L longevity. The enemy of engine life and most common cause of P&L demise are (i) lean running, (ii) insufficient oil and (iiI) FOB ingestion.

Acetone doesn't substitute for/replace nitro. They serve different functions. Nitro oxygenates the mixture, thereby increasing power (& heat), which is not a linear relationship to the percentile used. With the decrease in methanol percentile with the addition of significant percentages ie: >20% of nitro, you need also to move to a colder plug to maintain the flame due to the diminished catalytic effect from the reduced methanol.

Acetone's primary function is that of flamerate accelerant. I erred yesterday when I mentioned that it had no effect upon hygroscopic properties of methanol. It does when used in small percentages. Yóu will benefit more from using nitro than acetone if you must choose between the two on a cost basis. Almost everyone uses nitro in a minimum of 5%, but few use acetone. In NQ, whilst there's high humidity, the temps are also high such that the water won't come out of suspension. Experimentation reveals that methanol will combust OK with quite high absorbed water content.

For a home brew, stick with 5% nitro, 20% oil and 75% methanol. You can add 3% acetone if you want. Just be aware that if you use all synthetic, you'll have be especially careful to ensure that you don't tune lean because synthetic vaporises at a much lower temp than castor.

Righto Sigrun, I'm going use up the ingredients I have then go with the 5% nitro, 10/10% syn, castor, 75% methanol. Sounds like a safe compromise and I'll still be saving $$$. Thanks men for all your input. John.

For some info on acetone and other fuels we use go to http://www.holdfastmac.com.au/tech.html and then of course the obvious link. You can also check out some experiments I did by adding various percentages of water into fuel. Water never comes out of solution with methanol but excessive water drives the OIL out of solution.

Wow, that's a great test of water in the fuel, great job! And it really bears out what almost everyone "knows", even if it sounds like people are contricting each other.

So, it looks like a little bit of water isn't going to matter, but once you get beyond a certain point the oil comes out of solution and the fuel is garbage. And it looks like you can visually tell if there is a problem based on it being cloudy. I get that right?

One thing that just occured to me, your test engine was a "big" 1.08. I wonder if a smaller engine, like a .40 or .25 would be affected more by a smaller % of water in the fuel? I'm going to guess that some engines and some sizes are more sensitive to water content than others, and that the higher the operating RPM, the more the water matters? But that's totally a guess.

In the united states, fuel is about $15 per gallon. that's about 2.5-3 liters. that's for 20% nitro.

A US gallon is a bit more than that Spaceclam. ie: 3.785 litres.

Working on the current exchange rate +/- 2%, that's circa AUD$6- per litre for 20% nitro! Dunno' (Oz slang for "I don't know") what that'd cost me to buy pre-retil blended here, but I can't mix 20% nitro myself for that!

Your empirical testing makes an interesting read Brian, and John Modistach's summaries re fuel properties are useful. But "water never comes out of solution with methanol"? Methanol may have the property of being hygroscopic, as does air, but to suggest, nay state, methanol doesn't have a temperature interdependent saturation point? Convince me.

this price was for there blended oil 25% castor 75% klotz (or similar)

my home brew 5/20/75 mix costs me $2.96AUD a liter if i go to a synthetic oil with castor it'll bump up the price to $4.11AUD a liter.

Sooo cost wise may be i'll stick with my current brew untill i find a reason not to.

when you look at this price and consider the LHS is buying the ingrediance for a LOT less $$ than me it makes comercial or LHS blended fuels a bit of a rip off

also has any one tried the Shell racing M, it's the Shell version of the Castrol M BUT the Shell product is 35% synthetic, it's about $9.50 for a liter and $40 for a 5 liter, i've just ordered some to see how it goes

[QUOTE]Originally posted by Woodsy
also has any one tried the Shell racing M

Haven't tried it, but have used various brand, including Shell, mineral and synthetics in two stroke racing bikes over the years.

Observably different brand minerals or synthetics do exhibit different burn properties, but as a generalisation, when it comes to the synthetics in particular, they're much of a muchness insofar as empirical results reveal.

Argument and marketing abounds about which one is superior, but IME there really isn't a bad one in the market, individual engine design flow and combustion idiosyncrasies notwithstanding. But that's another story of exhaust flow design & Castrol TTS, otherwise an excellent lubricant.

Shell have been producing mineral and synthetic 2 stroke motorcycle oils for racing for some time now, so they should have their act together over this. In choosing my oil, if it meets spec., buy price is THE factor. At the moment, I use Mobil Racing 2T because neither their motorcycle product profile or advertising budget is as high as Shell's, nor are they as bike boutique as Motul which is reflected in the price.

Buy price on the Shell Racing M sounds mighty appealing to me as does the easy to obtain factor. Thanks for the heads up. I'll have a bo peep at their data and spec sheets if they're online and ask around to see if anyone in the club has trialed the stuff.

sigrun...methanol and water are both totally soluble in each other. There's no maximum either way. Now I'm no chemist but I'd suspect that methanol would stop absorbing water from the air when every methanol molecule is attached to a water molecule (or whatever the process of solubility is ).

Montague...I used the 1.08 because I figured I'd put my money where my mouth is and fly with the watered down fuel instead of just bench running and that was the only flyable plane I had. If you can call a 1.08 in a 6 pound beaten up 40 trainer a plane

The tests aren't conclusive of course but I've got no reason to think that a smaller engine would react any differently.

As far as that Shell Racing M goes, I'm pretty sure that not long ago someone (from Queensland?) reported in the RC Fuels section that he'd tried it and found it wasn't soluble in methanol.

Hello fellas, you know what? I'm just going to stick to Downunder's original advice and brew the the 3% acetone, 20% castor and 77% methanol. Downunder, you won me over (twice now) and there has been no evidence to dispute your claims. In fact your working from practical tests and not just theories. I have very limited experience and just want to brew my own fuel as cheaply and safely as possible. Your suggestions suit these needs. Thanks mate. Regards, John.

[QUOTE]Originally posted by downunder
sigrun...methanol and water are both totally soluble in each other. There's no maximum either way.

That water and methanol are miscible is agreed.

My scientific scepticism never implied they weren't. What I questioned was the veracity of your previous statement "water never comes out of solution with methanol" something quite different altogether.

To reiterate, if it's true (ie: not false), convince me.

From the Shell web site:

"A high performance castor/synthetic, SAE30 oil for 2-stroke and 4-stroke racing motorcycle engines. Shell Advance Racing M is specifically formulated for highly stress conditions experienced in speedway motorcycles and go-karts burning alcohol/methanol fuel mixtures. The castor/synthetic blend ensures longer life than a straight castor oil. It can also be used in separate 2-stroke and 4-stroke race gearboxes. Available in 1 litre and 4 litre."

i also rang the Shell tech dept (1300 134 205) and they gave me the castor/sythetic %'s and asured me it will mix, any way i've ordered a liter so i'll know soon, if it dosent i'll just use it for the jetski or trail bike

Hey Woodsy

Just a follow-up and comment mainly for your interest.

I checked retail pricing on Pro Glo product with my LHS yesterday. Just how long ago did you buy your castor for that quoted "$30"?

OK, now this particular LHS is sure to be asking SRP, but is usually no greater than 10% dearer than the average on marked retail pricing and, to his credit, stocks the full range of Pro Glow oils.

Before we continue, are you sitting down?

At the bottom of the rung is Lion's Pro Glo 1st Special Grade degummed Castor at a whopping $55- for 5 litres. If he's selling it for $55, I could guarantee it with the surety of Lloyds that all the other locals will be selling it for between $50 & 55-. The 1st Special Grade Advanced Degummed Castor (blue stuff) is $65 for 5 litres and don't even ask about the price of the pressed low viscosity bean oil. So if you're getting even the basic stuff for $30- for 5 litres, I'd buy up big now.

An intelligent guess suggests Lion have taken the opportunity since you last purchased to up the margins all around and demand price the stuff at a SR pricepoint just attractive enough to maintain pecuniary appeal, albeit begrudginingly, in competition with its Castrol M rival.

Just rang and checked as of now (Friday 29/8/03 4.19pm) here's what they have available at normal everyday prices.
Pro Glow (Lion)castor $6 bucks a liter
Prow Glow (Lion/Klotz blend)synthetic blend $16 a liter
Hobby headquarters castor $7 a liter
Morgans cool power $15.50 a liter

Isn't that an absolutely gobsmacking disparity? :spinnyeye

$30 in Melbourne vs $55 in Brisbane for what is presumably (?) the exact same product. PM me the URL of your shop if you wouldn't mind.

I'll have to shop around harder to see if I can find a source of VP or HHQ castor. I'm paying marginally less than the prices you quoted for Coolpower -per 3.68 litre jug buy through a friend- and less for Klotz trhough the club in a "bring your own container" buy.

I'm thinking of upping the castor content to 5 or 6%. With just 5% nitro used for sport flying, I am finding the lower viscosity 2-3% castor brew too temperamental on the needle even in the SE Qld winter heat and low relative humidity. 10%/10% works very well, but is messier that desired. Aim is to try and achieve the maximum synthetic content brew of a viscosity which will provide the desire needle setting characteristics on just 5% nitro.

I'll PM you the contact info, they dont have a web site, i'm surprised at the diferance in price considering hobby HQ (castor & morgans) is in NSW (should be as cheap to Brissy as country Vic) and the freight route from WA to QLD is via outback SA, NSW then QLD so only marginaly further than country Vic.

i wonder how much the freight is if i buy it and send it to you??
what suburb are you in? i have a mate that runs a local freight co. so i can ask if he could drop some off, although it would probably have to be a 20l to make it worth while.

Try Castle Hill Hobbies up in Sydney. They looked after me very well on 20 litres of Pro Glow Synthetic/Castor blend.

Thanks for the suggestion. Checked CHH website quite recently. Listed pricing inc. freight render the exercise null. Already have an alternative organised. Several of us will purchase bulk castor direct from the best priced wholesale supplier for a split between us.