Converting a propane stove to butane

[MickinOz]

Looking at stoves, now.
The "lunchbox" stoves that run on a slip-in 220g butane canister are rife in my part of the world.
Singles and double burners.

Single butane.JPG (46.78 KiB) Viewed 4226 times

The double burner, 2 can, propane stoves are simply left and right hand versions of single burner butane stoves joined together. With the cans at each end.
This makes them very long.

2 burner butane.JPG (23.08 KiB) Viewed 4226 times

Next step up is the Coleman type stove that runs on the screw-on 1 lb. bottle of propane/lpg
These range from the small basic one as below, on up to veryy flash ones.

coleman.JPG (35.44 KiB) Viewed 4226 times

The little green coleman above is compact, about the same price as the 2 burner propane stove, has at least part of a windshield (the lid) and will fit where I want to go.

But - those green 1lb gas bottles are not cheap in my part of the world. I can buy a 220g can of butane for $1.50 or less.
a 450-ish gram coleman propane bottle ranges from $9 to $15. So anywhere from 3 times the price for a given weight of gas, upwards.
I think I can only put in three pics, so see next post for actual questions.

[MickinOz]

So the little green Coleman, and a couple other basic stoves available locally, uses one of these:

coleman regulator.JPG (15.82 KiB) Viewed 4221 times

Now, online you can buy adapters that will convert 220g can to a Coleman type thread:

adapter.JPG (30.48 KiB) Viewed 4221 times

So, at that point, you have a butane can (very cheap) connected to your coleman propane stove (also very cheap, and the right size for my application).

I'll answer the inevitable questions now:
Yes, I know that butane is useless in really cold conditions. I live in South Australia - not often an issue, that's why the little lunchbox stoves sell well. Butane and propane by weight only differ about 5% in energy. Flame temperature is nearly identical.
No, a 2 burner butane lunchbox stove does not suit my needs.
No, plumbing in propane is not going to happen. The moment I do that, I have to have the 'drop inspected and certified by a gas technician.
Yes Coleman type 1lb bottles are, sort of, "readily available". But they aren't as readily available as the butane cans and they are a minimum of three times the price weight for weight.

So now, with the backgrounding out of the way, I'll ask my questions:
Has anyone run butane in a Coleman propane stove?
Did it work satisfactorily?
Do you still have all your fingers, both your eyes, and your hearing?

[NevadaBlue]

You can also get an adapter hose that allows use of the 1 pound propane cylinders as well as any that uses the standard POL connector. I bought a 5 pound cylinder for my little trailer, to power my two burner stove.

Something like this will do it.

CDBC4988-3E8D-4CF1-904B-B475AE0A251F.jpeg (44.89 KiB) Viewed 4183 times

I also sprung for the Flame King refill kit and cylinders which allow safe, legal refill of 1 pound bottles. Good stuff.

[MickinOz]

Thanks Blue.
I'm a little late getting back to this thread.

I'm wanting to go the other way.
Here in Oz we seem to have the opposite situation to North America.
The price of those one pound propane bottles in Australia is ridiculous, and pretty much only camping stores sell them.
Unlike the little 220g butane canisters that are very common and very cheap.

Refilling has its problems too.
There is an adapter available to enable a butane can to screw on where the 1lb propane would go.
Looks like I may have to do some trailblazing - I can't find much about it.
Here in Oz, a propane stove's specs will say its LPG.
One of the biggest suppliers, ELGAS, says that LPG can be propane, butane or any mix of the two.
Apparently ULPG, meaning universal LPG. is the spec to look for. I have found one brand that says the stove suits ULPG.

[troubleScottie]

I have not actually done what you are doing.

However -- butane and propane appear to be interchangeable for small cook stoves. They generate approximately the same amount of heat by weight. For broad range of temperature, small cook/camping stove use a iso-butane/propane mixture. The mixture is lower pressure, so thinner metal walls and a lighter can. Iso-butane and n-butane (what is in the cheap butane cans) have about the same vapor pressure, generate the same heat, but have different boiling temperatures.

Methane ( natural gas) versus propane. Major difference in heat per volume of gas. Propane generates about 2.5 times the heat. To convert between the two requires changing the orifice on the fuel line.

So back to propane vs butane. Generally the difference is the values on the top of the cans. There are converters: G-Works might be the best brand -- a bit pricey but very nicely machined. There are others. There are lindahl (hiking stoves), nozzle bottle/butane canister and propane connectors. I think there is another variation for European containers.

There should be one that will convert your gas bottle to the intake connector. Possibly you will have to connect two together. Just get the genders correct. The description states which type it is going "from" to "to". The "from" part will connect to the top of the container type. The "to" part would be considered what the top of the gas bottle would be for that the gas type device.

Obviously the connectors add length to the setup ie the bottle and fitting may not fit into a particular space. There are some converters have hoses between the two fittings.

[MickinOz]

Thanks.
Yes, the correct adapter for the job is available.
There doesn't appear to be any reason it won't work.
One of the few issues I can see is that there is a lot less surface area in a butane can for boiling off the gas.
It may be it just plain can't supply enough.
I note even the coleman propane can is always shown tilted at an angle. It may be for convenience, but I bet it doesn't hurt performance to have the surface area of the gas/liquid interface increased.
I will probably give it a try.

[NevadaBlue]

Sorry, I misunderstood what you wanted to do. Yes, you can get that adapter that connects the butane cylinders to the stove in the place of the 1 pound propane cylinders. Be aware that the butane cylinder is ‘keyed’. If laid down, it needs to be at an angle with the proper side UP so you get butane gas, not liquid. Standing up is OK.

[MickinOz]

Thanks Ken, I hadn't really thought about that. The canister stoves do that, there's a tab that makes sure the notch in the collar is always up.
I'd have to pay careful attention to that.

[GTS225]

Now....here's the unasked, and unanswered question.
How many butane canisters will you go through, in actual usage time, compared to a 1-lb propane canister?
That remains to be seen, as only experimentation and field use will show that comparison. It may be that the cost-per-minutes used will be relatively equal, in which case you've lost nothing in the conversion, and gained availability with the butane supply, as compared to propane suppliers.

Roger

[MickinOz]

The question has been indirectly answered earlier in this thread. In fact it is pretty much what the thread is about, but I'll answer it again.

Weight for weight, energy content of propane and butane differ by about 5%.
A 1 lb bottle of propane was $17 at two different shops in my home town today.
The local Kmart is has 12 packs of butane canisters for $16. That's 5.8 lbs of butane.
The stove would have to use 5.8 times as much butane as it does propane to make the costs equal.

Anyway, having said all that, I have another solution floating around that may cause this discussion to remain theoretical.

[saltydawg]

Have you thought about using the 1lb bottles and refilling them from say a 20 lb bottle of propane. Here I can get a 20 lb propane filled for less than 10 bucks. Thats 50 cents a lb. or 5.8 lbs for 3 bucks.

[MickinOz]

Can do it, it isn't as cheap as the US but not too bad.
But there are legal problems.
They are real sticklers about expiry dates on the 9kg bottles.
There is a thread on here about a guy refurbing a gas cylinder himself. It'd never be allowed here.
I have a cylinder that cracked 10 years sold last year. It only ever had one refill in that ten years (I haven't done a lot of BBQ-ing since I built the wood fired oven) and it was only a couple months out of date.
Couldn't get it refilled.
And it isn't legal to refill yourself.

[troubleScottie]

Flame King makes a US legal refillable 1 lb propane bottle. Slightly thicker walled with a relief valve. Oddly, you can only buy 1 per order. Not sure on any expiration dates.

They also sell a refilling valve, a refillable bottle and stand for refilling from up to a 20 lb tank. Pretty straight forward outdoors away from flames process.

The various adapters with male to male fittings eg Flame King above and specialized lindahl to lindahl eg G-works allow transfer between tanks. The later is used to transfer the dregs from one container into an almost full container.

[NevadaBlue]

I bought 4 of the Flame King bottles at one time on Amazon. Like lots of things right now, Amazon is out, but oddly, Flame King is selling them directly on eBay.

[MickinOz]

So today, I received my butane adapter.
This one:

adapter.JPG (30.48 KiB) Viewed 3080 times

So I hooked her up, opened the valves and lit the burners on the vintage primus.
They ran OK, but I could hear and see that the flow was greatly reduced.
I filled the coffee pot to the first hole, put it on the stove, hit the timer, inserted a thermocouple in the water and put the lid on.
Time to reach a rolling boil at an indicated 99.3 C was 20 minutes.
Only a couple of grams of weight loss on the butane canister.

Then I set up the experiment again, this time with the propane.
Clearly more than double the flow.
Time to reach boiling at an indicate 99 degrees was 6 minutes
Again only a few grams of weight loss.

So first conclusion re: adapting butane to propane:
"Cylinder pressure" stoves, i.e. unregulated stoves, have quite small jets that flow the right amount of gas at propane cylinder pressures. Butane cylinder pressure is incapable of pushing enough flow through the small jets.
At test conditions propane gas pressure is around 860 kPa, while butane has a pressure around 215 kPa.
Flow rate, all other things being equal, is pretty much proportional to the available pressure.

So, butane isn't much good in a stove built for "cylinder pressure" propane. I'd have to re-jet, I'm thinking.

The next thing to try would be a regulated pressure stove.
Seems a coleman regulator outlet is around 110 kPa, so the cylinder pressure of butane should be enough.

That test will have to wait, until I come across a suitable stove to try.