Hey, gas canisters are expensive. Why NOT just refill them with cheap gas from a bulk propane tank?


A "bulk" propane tank


Yeah, and on eBay you can get a cheap canister refiller that will do just that.

A very dangerous canister refill adapter


But refilling backpacking canisters with this particular canister refiller is inherently dangerous. Find out the whys and wherefores in my latest post:
Canister Refiller -- WARNING

HJ

No idea if this is a real problem or not. I don't know what the little canisters are rated for. It does seem plausible though.

lol. Thanks for your vote of confidence.

Backpacking canisters are generally intended for a blend of gasses, typically propane with either butane or isobutane. When you blend gasses, the resultant mixture has a vapor pressure somewhere between the various vapor pressures of the constituent gasses.

Now, go look on line or in stores. You will find no brand with more than 30% propane. A little flimsy (by comparison to 100% propane car camping canisters) backpacking canister just isn't built for 100% propane.

HJ

You certainly won't catch me anywhere near such a disaster-waiting-to-happen.

HJ

I am assuming you're referring mostly to the lightweight gas canisters for backpacking stoves? In which case I would agree with you, I'd never try and refill them.

Here's a diagram on the vapor pressures of different mix ratios

http://www.engineeringtoolbox.com/propane-butane-mix-d_1043.html

You can see that propane has a much higher pressure compared to butane

However, I do have a coupler for filling the small 1 lb propane bottles from the larger bulk tanks, but those 1 lb bottles are built a lot heavier than a standard stove canister. Even though I've read refilling those aren't recommended, but I've never had a problem and the risk seems much lower.

Nothing "mostly" about it. I am referring to the lightweight dome shaped canisters for backpacking stoves.

I believe they can be refilled safely -- just not with 100% propane.

The key thing here is to know the max weight before you start and never refill to greater than that weight. Overfilling is a sure way to have problems.

HJ

Where's Blast? I bet he invented that tube!

(I'm joking! I hope ... )

Maybe not, but I bet he could have, er, a "blast" with it. lol.

HJ

Have no fear, Blast is here! Let just order the gizmo and...funny, the back of my neck suddenly feels warm

...oh.

-Blast, being glared at by his wife.

Why is that NOT in either safety lime-green or safety orange? I'd buy it!