# Forum Home Renovation Metalwork & Welding  Old 45kg gas bottle

## ajm

Folks, I'm open to suggestions on this one. Thought I would try to find an old LPG bottle, one of the large upright ones, to convert into a water filled lawn aerator. Once the gas bit on the top has been removed, will weld triangle shaped metal bits all over it to rip up the ground. Thought these would be stronger than spikes. 
So, any ideas where I would find an old bottle with the top removed? 
Slk

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## cyclic

Metal recyclers, 
lpg suppliers. 
Facebook Marketplace 2 for $30 Gold Coast 
You may have to unscrew the valve yourself  
and when welding either fill with water or 
run a car exhaust through the bottle to get rid of any excess gas to stop the bottle and you going BOOM

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## cyclic

Another 2 bottles on facebook market place at Caboolture for $50 
Welding old gas bottles is dangerous as they may still contain gas. 
You have been warned.

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## Whitey66

> Another 2 bottles on facebook market place at Caboolture for $50 
> Welding old gas bottles is dangerous as they may still contain gas. 
> You have been warned.

  He's only welding it after the top of the bottle is removed according to his first post, he mentions this twice.
One question ajm, if you remove the top, how are you going to keep the water in?

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## cyclic

> He's only welding it after the top of the bottle is removed according to his first post, he mentions this twice.
> One question ajm, if you remove the top, how are you going to keep the water in?

  Yes Whitey, I am aware of what is in the OP, however, a gas bottle, even with the valve removed, can still hold flammable/explosive gas.  
The Op by their own admission, knows nothing about welding let alone welding of gas cylinders (see the post on welding/stick welder from AJM) 
Do it once, do it safe. 
Many people have died welding/cutting/repairing empty bottles/fuel tanks etc

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## Whitey66

> Yes Whitey, I am aware of what is in the OP, however, a gas bottle, even with the valve removed, can still hold flammable/explosive gas.  
> The Op by their own admission, knows nothing about welding let alone welding of gas cylinders (see the post on welding/stick welder from AJM) 
> Do it once, do it safe. 
> Many people have died welding/cutting/repairing empty bottles/fuel tanks etc

  With the top removed it is no more dangerous than welding a metal bucket.

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## phild01

> With the top removed it is no more dangerous than welding a metal bucket.

  I wouldn't like to assume there is no gas even if the top is removed, LPG being heavier than air!

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## Whitey66

Clutching at straws here, tip it upside down and pour the gas out then  :Smilie:  
He was asking for a bottle that has already got the top removed, he didn't say he was going to drain a gas bottle remove the top then instantly weld spikes on it.

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## droog

With lpg it’s not just the gas, the surface can be impregnated and coated with some remaining mercaptan which is the odourant used in lpg.

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## Bros

> With lpg it’s not just the gas, the surface can be impregnated and coated with some remaining mercaptan which is the odourant used in lpg.

  I've made quite a few cookers out of 9kg bottles and that smell seems to never leave the bottle.

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## Whitey66

I wouldn't be too worried about Ethyl Mercaptan when welding an LPG bottle. Anyone who is exposed to a gas BBQ, Un-flued gas heater, gas cooking oven and cooktop etc etc. would be exposed to more Ethyl Mercaptan than someone who was welding an old empty gas bottle. Natural gas also has Ethyl Mercaptan added as well (it's odourless and colourless naturally just like LPG), so any burning of either gas will expose you to it. Or are you referring to its flammability?
Granulated pool chlorine and water neutralises Mercaptan from memory, but don't quote me on that.

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## droog

> I wouldn't be too worried about Ethyl Mercaptan when welding an LPG bottle. Anyone who is exposed to a gas BBQ, Un-flued gas heater, gas cooking oven and cooktop etc etc. would be exposed to more Ethyl Mercaptan than someone who was welding an old empty gas bottle. Natural gas also has Ethyl Mercaptan added as well (it's odourless and colourless naturally just like LPG), so any burning of either gas will expose you to it. Or are you referring to its flammability?
> Granulated pool chlorine and water neutralises Mercaptan from memory, but don't quote me on that.

  Its not the smell or the mercaptan itself, it’s the remains left inside the cylinder. You wash it out and then start welding, the heat releases the flammable components trapped in the surface or residue left behind. 
With thorough washing, time and heat it can be safe to work on but don’t just give it a rinse and assume it’s good to go.
Filled with water is a safe way to start for cutting the top off.

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## Whitey66

> Its not the smell or the mercaptan itself, it’s the remains left inside the cylinder. You wash it out and then start welding, the heat releases the flammable components trapped in the surface or residue left behind. 
> With thorough washing, time and heat it can be safe to work on but don’t just give it a rinse and assume it’s good to go.
> Filled with water is a safe way to start for cutting the top off.

  Too late, I've cut, welded and ground many empty LPG gas bottles, maybe 30 or more and have never had any issues at all. Made all sorts of things out of them like heaters, fire pits, pizza ovens, garden art etc. The danger of welding a gas bottle is worse if the bottle is fully sealed, not when it has the top removed. I've also welded many petrol tanks on cars and motorcycles, when welding car fuel tanks I run the car exhaust gas through them to remove any oxygen but with motorbike tanks I just leave them out in the sun till there is no residue left.

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## droog

> Too late, I've cut, welded and ground many empty LPG gas bottles, maybe 30 or more and have never had any issues at all. Made all sorts of things out of them like heaters, fire pits, pizza ovens, garden art etc. The danger of welding a gas bottle is worse if the bottle is fully sealed, not when it has the top removed. I've also welded many petrol tanks on cars and motorcycles, when welding car fuel tanks I run the car exhaust gas through them to remove any oxygen but with motorbike tanks I just leave them out in the sun till there is no residue left.

  Same here, never had issues with cutting or welding gas cylinders, fuel tanks or drums, I take a cautious approach and assess the risks before attempting any hot work on fuel containers.
Plenty of others have experienced issues with some resulting in injury, better to be aware that issues exists and determine for yourself if you have addressed the risks and if it is safe to perform the work. 
Otherwise, carry on.

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## ajm

Guys, I really do appreciate the safety focus. It's way easy to hurt yourself. The gas bottle idea came to me when carting our empty back to the store. So heavy compared to those tow behind aerators you see with the spikes on them.  Would a stick welder create a strong enough join between the lugs and the bottle if it was to be used to tear up the ground? Also, if it was filled with water when welding, would this be enough to manage any ongoing risk from going boom?Sk

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## ajm

> Metal recyclers, 
> lpg suppliers. 
> Facebook Marketplace 2 for $30 Gold Coast 
> You may have to unscrew the valve yourself  
> and when welding either fill with water or 
> run a car exhaust through the bottle to get rid of any excess gas to stop the bottle and you going BOOM

  Run a car exhaust through it? The fumes from the exhaust or the exhaust pipe itself? Am intrigued.
alk

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## droog

It is the skill of the operator performing the weld where the strength lies, not the welder itself.
For a rolling aerator the diameter of the roller and the length of the tines will play heavily on the forces as they have a bending force applied as the imbedded tines roll past vertical. 
Practice some welds on scrap and see if you can break the weld. 
Filling with water to cut the top off is the safest bet if you have any doubt about the cleaning process. Once the top is off the risk of explosion is minimal, even if there is some remaining surface contamination any off gassing is open to the air and in not contained.

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## droog

> Run a car exhaust through it? The fumes from the exhaust or the exhaust pipe itself? Am intrigued. 
> Sent from my SM-A205YN using Tapatalk

  The exhaust gasses, not the exhaust pipe.

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