I'm not after a Chef's blowtorch... I have a Brulee Iron...
Well you did ask.
However the fact you blowtorch has an internal reservoir explains the warnings on it in respect to % of propane allowed and not keeping it in excessive temps. The Reservoir has a limitation on the maximum developed pressure it can hold.
With respect your assertion regarding Propane being dangerous is correct for this type of appliance. But a bit of a stretch for say a canister stove using a canister approved to EN 417 or DOT 2P they are designed to withstand the pressure of the LPG mix that is in them.
You're right, and I didn't mean to imply that canisters were not safe to contain the gases which are sold in them. Reading my post again I can see that it could have been a lot clearer.
Assuming someone hasn't refilled a thin walled EN417 type canister with 100% propane which you will not get commercially. Then canisters are safe and the risk of them going off like a 'grenade' is low in normal day to day situations.
Again you're right. My concern was mainly things like the refillable blowtorch which could be filled with the wrong gas or gas mixture, or using one manufacturer's appliance with another manufacturer's gas. People do sometimes try to reduce costs doing outlandish things with gas bottles. They will often observe the natural selection process at first hand.
What is possibly an issue is the aeration and orifice size in the appliance jet. Very generally speaking a given aeration rate and orifice size works for a given gas type but can give problems with another. So simplistically butane burns optimally in one combination Propane in another and mixes in another. ... Anyhow.. If you're running Butane in an appliance designed for Propane you might find the appliance soots a bit. Not every appliance will some might. The risk with sooting is the associated production of CO which might be a concern.
More good advice. Usually a domestic regulator will supply butane at 28 millibars or propane at 37 millibars (very low pressures, a fraction of 1psi). In theory this will help with the aeration issue.
I've yet to see a stove that specifies the butane/propane mix. (I confess to not studying them in the greatest of detail!)
All gas stoves have specifications for their safe operation. They are all sold with instructions for their safe use. Read and obey the instructions. To do otherwise is to ask for an incident.
In much the same way that caravan appliances can run on pure butane, pure propane or a mix of the two.
It would be unwise to assume that any particular appliance can be used with any particular fuel. There will have been a document supplied with the appliance when it was new, stating the intended fuel(s). Most caravan appliances need a regulator. The regulator isolates the appliance from the pressure in the bottle. The pressures in the bottles will usually be many times greater than the pressures experienced by the appliance and the local pipework, which do not need to (and probably could not safely) cope with the pressures in the bottles. As noted above the pressures which most caravan appliances use are typically a fraction of one psi. The pressure in a propane bottle can easily exceed 200psi. Some regulators are designed for use with either butane or propane. It would be unwise to use a butane regulator with a propane bottle, and one of the reasons that there are so many different types of thread on gas bottles is to prevent this kind of thing from happening). It would be unwise to use any appliance without first establishing the fuel which it is intended to burn.
There are also industrial regulators which generally supply much higher pressures, and adjustable regulators which can supply a variable pressure which may be much higher than the pressures for domestic use. They should not be used for appliances which are not designed for use with them. They are sometimes stolen from building sites etc. and find their way onto gas bottles on caravans. I have found them myself on caravans that I have bought.
In the UK, there is a substantial body of legislation covering pressurized gas containers, regulators, their use, storage and transport.
Regulated supplies aside, my main concerns are
(1) There are refillable lighters and similar which are designed for use with pure butane and which could easily be filled using a butane/propane mix from the container supplied to refill the wife's kitchen blowtorch. If the lighter is intended for use with the mix then all is well. Otherwise it might not be.
(2) Amongst other things this thread has included discussion of using one manufacturer's stove with another manufacturer's gas bottles. The manufacturers will in all cases say "Don't do that." or words to that effect IN WRITING in the instructions which they supply with their products, should anyone care to read them.
Scaremongering won't help anyone wanting advice. After all you MIGHT get run over by a bus tomorrow.
You are much less likely to be run over by a bus if you follow the recommended procedures, and you are much less likely to be killed by a stove if you follow the manufacturer's instructions.
It's not so much scaremongering, as imploring people to use that squishy grey thing between their ears.