# How do I completely empty a Calor gas cylinder to cut it?



## Graham Orm (12 Feb 2013)

I have decided to build a rocket stove using old Calor gas bottles and a co2 cylinder for the inner pipe. (I plan WIP pictures). A visit to the local scrap yard yielded 3 Calor bottles and a co2 bottle completely free of charge. What I need to do now is cut them open and prepare them for welding. Any ideas on how I should tackle puncturing and cutting them? Obviously I have the means to cut them, it's the big bang that I'm keen to avoid.

I thought of drilling a hole initially, whilst soaking the bit with WD40, also possibly submerging the bottle in water to stop any sparks. One of the calor bottles already has a hole in it that the guy said had been done with a pick axe. The bottle stinks of gas, indicating that there must be some residue.


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## Dangermouse (12 Feb 2013)

I'd rather play with a stick of dynamite near a fire ! :shock:


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## porker (12 Feb 2013)

Make sure all the gas is out of it by de pressurising the cylinder. Remove the valve. This may be very tight so you may need a big pair of stilsons. Fill with water. Leave for a day. Cut with whatever you are going to use. Some people drain the water first some don't. (also depends on what you are using to cut it).

(I'll skip over the minor detail that if they are Calor cylinders they belong to Calor and they don't like people cutting them up.) I've done a few and never had any problem.


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## Graham Orm (12 Feb 2013)

porker":35ehowk7 said:


> Make sure all the gas is out of it by de pressurising the cylinder. Remove the valve. This may be very tight so you may need a big pair of stilsons. Fill with water. Leave for a day. Cut with whatever you are going to use. Some people drain the water first some don't. (also depends on what you are using to cut it).
> 
> (I'll skip over the minor detail that if they are Calor cylinders they belong to Calor and they don't like people cutting them up.) I've done a few and never had any problem.



OK They have a brass gizmo sticking out....am I right in thinking this is a left hand thread? They are not calor I should add, and were in the scrap yard so no harm done eh?


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## Graham Orm (12 Feb 2013)

Dangermouse":1hlkvpfr said:


> I'd rather play with a stick of dynamite near a fire ! :shock:



That's next! :mrgreen:


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## Cowboy _Builder (12 Feb 2013)

I've cut into a few of these sort of bottles ,i just open the tap and let whatever gas there is out or you can put the regulator on and ingnite whatever comes out with a blow lamp it can't burn back through the regulator ....then just cut into it with an grinder.
Remember that Calor bottles remain the property of the company ,so i'm sure it's not a Calor bottle you have..... is it ? no i didn't think so


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## porker (12 Feb 2013)

I think they are right hand thread. The ones I have done are butane (blue) and are right hand thread. Not certain about propane.


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## Graham Orm (12 Feb 2013)

Cowboy _Builder":2b03uddg said:


> I've cut into a few of these sort of bottles ,i just open the tap and let whatever gas there is out or you can put the regulator on and ingnite whatever comes out with a blow lamp it can't burn back through the regulator ....then just cut into it with an grinder.
> Remember that Calor bottles remain the property of the company ,so i'm sure it's not a Calor bottle you have..... is it ? no i didn't think so



DEFINITELY not


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## Graham Orm (12 Feb 2013)

Thanks for all the advice guys, as usual, priceless.


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## Cheshirechappie (12 Feb 2013)

Please forgive me if I'm missing something, but couldn't you just have obtained a couple of lengths of thick-wall tube or pipe? There must be thousands of tons of pipe, tube and structural round hollow section lying around in scrapyards.


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## No skills (12 Feb 2013)

Yes, but then you have to pipper round making a base for the tube and then a top and then... The gas bottle burner seems popular ATM and easy to do, and theres no guess work involved - getting the wall thickness wrong on a bit of tube could lead to a saggy burner  


*Sorry, that reads as a bit flippant - wasnt ment to be.*


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## deserter (13 Feb 2013)

Looking forwards to the WIP I've wanted to have a go at this for a couple of years now. 



~Nil carborundum illegitemi~


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## Graham Orm (13 Feb 2013)

Cheshirechappie":186xudj0 said:


> Please forgive me if I'm missing something, but couldn't you just have obtained a couple of lengths of thick-wall tube or pipe? There must be thousands of tons of pipe, tube and structural round hollow section lying around in scrapyards.



Nope, or I would have. :wink:


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## jasonB (13 Feb 2013)

Be aware that propane is heavier than air so just opening the valve will not let all the gas out, even if you turn it upside down some will remain so purge with water or Co2.

J


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## Cheshirechappie (13 Feb 2013)

Grayorm":2jrhah9o said:


> Cheshirechappie":2jrhah9o said:
> 
> 
> > Please forgive me if I'm missing something, but couldn't you just have obtained a couple of lengths of thick-wall tube or pipe? There must be thousands of tons of pipe, tube and structural round hollow section lying around in scrapyards.
> ...



Fair enough!


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## Cheshirechappie (13 Feb 2013)

No skills":u0719dkk said:


> Yes, but then you have to pipper round making a base for the tube and then a top and then... The gas bottle burner seems popular ATM and easy to do, and theres no guess work involved - getting the wall thickness wrong on a bit of tube could lead to a saggy burner
> 
> 
> *Sorry, that reads as a bit flippant - wasnt ment to be.*



Not flippant at all - perfectly sensible answer to the question, for which, thanks!

P.S. I can see how you'd prefer to avoid a saggy burner....


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## Tinbasher (13 Feb 2013)

To be super safe fill it with water.


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## graduate_owner (13 Feb 2013)

I did a welding course some years back, and the advice for welding things like fuel tanks was to steam the fuel reside out for a few hours. Having said that, I really don't see how any gas could be left in the cylinder if it is full of water, as has been suggested.

K


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## Robbo3 (13 Feb 2013)

Haven't seen any advice yet on how the OP should get rid of any heavy ends.


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## Graham Orm (14 Feb 2013)

Robbo3":3mq9yom5 said:


> Haven't seen any advice yet on how the OP should get rid of any heavy ends.



Heavy ends??


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## spinks (14 Feb 2013)

I am assuming, by heavy ends, Robbo must mean any build up of flammable residue that may be in the cylinder. Propane, Butane and other "anes" like methane, heptane etc etc are whats known as light ends in the refining industry and will contain a minute amount of heavy ends such as naptha or gas oil. thats why the cutting when its full of water is the best option.

Of course I could be barking up the wrong tree completely!!


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## RogerBoyle (14 Feb 2013)

Robbo3":1xw1agr3 said:


> Haven't seen any advice yet on how the OP should get rid of any heavy ends.



It was posted two above yours LOL



Tinbasher":1xw1agr3 said:


> To be super safe fill it with water.



By doing so it purges the gas


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## Heath Robinson (14 Feb 2013)

You are indeed right. Heavy ends are indeed a black gunk left behind in gas systems. You see it in the evaporator units in LPG-fuelled cars, and all the associated gubbins. Solvents are your friends here.


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