Converted my Optimus 99 from white gas to alcohol!

Recently converted my Optimus 99 stove to run on isopropyl alcohol, and little thing runs like a jet engine! No ill effect so far, boils water super fast.

Bought a spare jet nozzel and drilled it to ~0.6mm, put it back together and it goes straight up! and I can revert it back to white gas anytime, just need to purge the wick.

The flame is actually bit larger than running white gas, likely because the larger jet hole, I had to turn it down little bit because it became bit scary.

I also tried ethanol which also runs okay, but anything below 90% it struggles to get pressure up.

No smell, no burning mark, no smoke, no soot (so far). The flame goes bit orange when on full blast, but once turn down slightly it remains pure blue. Overall pretty happy with the result!

 

Nice. Is that cheaper than white gas? Or just something you wanted to try?
Duane

 

Thanks!

Bit both, coleman fuel at where I live is 30CAD before tax for a gallon, 99% iso alcohol is only 25 for 4L(about 200ml more than a gallon). Also interested to see if I can make it to burn as odor free as possible so I can use it as an indoor coffee stove (plus alcohol is bit safer to use and store).

 

Great little experiment!

Alec.

 

Drill press to slowly drill out the jet?
Duane

 

Not the usual characteristic of a pressurised alcohol burner in my experience, but I’m not questioning your judgement.

 

Way cool experiment! Isopropanol has a higher energy content than methanol or ethanol, which is great, but it's principal drawback has always been that it soots horribly. So it looks like you have figured a way around that!

One word of caution about it burning indoors - unburned isopropanol (unlike ethanol) is toxic so depending on how cleanly it burns it may or may not be an issue. Same with CO, which is odorless, so you can't tell just by sniffing.

I wonder if one can do this conversion for any self-pressurizing white gas stove? (Thinking 123). It would depend on vapor pressure, and also boiling point... one wouldn't want to pop the safety valve if the isopropanol starts boiling

 

For all the reasons @PWDolkas cited I'd recommend ethanol and avoid isopropanol at all costs. If you use Everclear brand ethanol you can also fix yourself a cocktail using stove fuel. A little for the stove, a little for the cook!

Ben

 

“Snakebite Remedy”.

Be sure to obtain the genuine article - the fine people at Everclear were forced by the neo-Prohibitionists to offer an ersatz, reduced-potency version in some markets.

 

This is interesting. A high performance pressurized alcohol burner.

Is there any reason methyl hydrate would not work?
I share the concern re toxic fumes and CO if used indoors.

Here in BC ever clear is unobtainable-I have never found any. The closest is ethanol marketed for marine alcohol stoves. Not drinkable!

 

Thanks!

 

Yes, I actually just used a small manual drill, it is super easy to work on brass

 

Ya, I have to be clearer tho, not as fast as gas, but faster than my usual impression about alcohol stove, I think it has to do with the fact that I'm usuing 99% iso alcohol

 

Thanks!

Ya, I had it ran 30min in my washroom mutiple times today (with vents on), no soot at all, I think if the mix and jet speed are ideal it wont left soot, blue flame all around.

Regarding the isopropanol fume, ideally it is jetted in gas form, and should burn fairly clean, but like you mentioned, might be better to move back to ethanol for indoor use.

I think with proper modification this conversion can be done in many other stoves, but really depends on the stove design and ideal jet size. For instance, the Optima 99 after conversion requires longer pre-heat before it can self sustain. It also became more sensitive to cold wind, I put it close to my AC vent, when AC comes on I can hear the pressure drop at the jet. With white gas it wasn't this sensitive.

I won't worry about the safety valve tho (I serviced it with new gasket and bit silicon lube), tested the safety valve using compressed air (Probably with a pressure regulator next time to figure out a number), the spring loaded valve works more like a constant pressure regulator. Iso boiling point rise as pressure rise, when pressure reach safety valve limit it let go some pressure so the tank has a somewhat constant pressure to drive the jet and maintain a self balanced system. The only time it scared me was when I was testing it with wind, when wind blows through the flame towards the tank, the flame actually went right above the tank and the pressure rapidly increased, I think I heard some bubbling inside the tank and the safety valve made a hiss noise (the flame was too noisy to be sure), but then it went back normal.

So the second time I let the stove reach peak heat with a pot on top of it, put a tube that's bit larger than the fill cap, let it run, then gently removed the tube and quickly put a lighter to the tube, the vapor inside the tube actually made a quick flash so this tells me that the safty valve is slowly releasing over pressured vapor (or simply leaking). I'm really qurious about what pressure is inside the tank tho, maybe one day I will figure out a pressure gauge and adopt it to the cap, knowing the actual tank pressure would make a lot less gussing.

 

Ya, I will use ethanol for indoor, the reason I tested iso alcohol is I got access to 99% pure iso at the moment but the ethanol I got is 90% regen, and from I what tested, the 90% regen is bit hard to get going.

 

I'm in BC as well, the reason I didn't test meth is because it is bit more toxic than iso (more severe effects). But I don't see why it wont work (with reasonable concentration).

Like others said, probably ethanol is better for indoor, but I think all will be fine if it's used outdoor.

I will see what I can do to make 90% ethanol work better, that be the most ideal case (I have access 99% ethanol, but that would defeat the purpose of been cheaper), otherwise I personally perfer iso than meth.

 

Cooked a pot of instant noodle today, all is well!

 

Interesting, I wonder what will happen in the tank if you used a screen like on the 111 instead a wick.
Thank for sharing

 

Everclear 190 proof is 95% pure ethanol.



Ben

 

In Tucson, AZ, Everclear 190 proof is $16 for a Fifth [750 ml] at Total Wine. KleenStrip DeNatured Alcohol about $20 a gallon at Home Depot. Coleman gas about $14 at Walmart. [They were out of Crown.]
I bought 5 gallons of Racing Methanol at $5/gal at my local Hot Rod Shop. [I had to bring my own jerry can.]

I'm about ready to convert one of my Optimus 8Rs into an 99. I have most of the parts sorted.
Making it an Alco-burning 99 is interesting. I need a spare Jet and a .06mm drill bit.
Do I need the Alcohol Restrictor tube that the 111Ts use too?