I was talking about blowing with compressed air, not filling it up and making the tank pressurized
- Thread starter diogofcr
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For a bang you need fuel, air and source of ignition, they come full of fuel, so blowing air in then adding adding heat doesn't seem ideal. if you add water all the fuel is pushed out, then air goes in after the water and before the spark. Not saying anyone is wrong, clearly no one who has posted here has been blown to bits, it just seems to me water is a much safer way.
skotl
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Can someone attempt to explain the science behind "going at it as soon as possible", please?
If we agree that steel is not porous, and that it can't suck in the fumes, why would a tank be more dangerous 4 days after being filled with water and blown with air, than it would 1 hour after that happened
If we agree that steel is not porous, and that it can't suck in the fumes, why would a tank be more dangerous 4 days after being filled with water and blown with air, than it would 1 hour after that happened
I was told the odor substance (Ethyl Mercaptan) was absorbed by the steel, but I may be wrong??Can someone attempt to explain the science behind "going at it as soon as possible", please?
If we agree that steel is not porous, and that it can't suck in the fumes, why would a tank be more dangerous 4 days after being filled with water and blown with air, than it would 1 hour after that happened
gordon stephenson
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No, Because for an explosion to take place there has to be a certain percentage of gas present, with the air purge there is probably 99.9999% fresh air,
The smell is still usually still there. Probably impregnated into the dirty surface inside the cylinder
Cutting straight after purging is because at that moment you know the cylinder is clean,
The smell is still usually still there. Probably impregnated into the dirty surface inside the cylinder
Cutting straight after purging is because at that moment you know the cylinder is clean,
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addjunkie
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Gas only ignites/ expodes when you have 3 things as said earlier, ignition source fuel and oxygen.
With gas you then have the upper and lower explosive limits, ie if there is not enough gas it wont burn or if there is too much gas it wont burn. With propane its about 2% by volume to 10% by volume it will burn. With methane about 4 to 15 %.
So chuck in a match might be too high to ignite. After a few days the gas has disperesed, chuck in a match it will ignite.
If you replace all the air ( oxygen) with an inert gas, ie argon, co2, nitrogen it wont ignite either as the oxygen has been removed, no matter how much gas is left in there.
Dont forget too some gasses are heavier than air others lighter, so this can effect if you have the bottle the right way up or not, when purging.
And yes people do die when they get this stuff wrong
Like I said earlier I do this for a living on a much larger scale. When I do one at home I remove the gas first but priming with warm water. As the water is more dense than the gas regardles of its state( liquid or gas phase) the gas comes out the top as the water goes in.
With gas you then have the upper and lower explosive limits, ie if there is not enough gas it wont burn or if there is too much gas it wont burn. With propane its about 2% by volume to 10% by volume it will burn. With methane about 4 to 15 %.
So chuck in a match might be too high to ignite. After a few days the gas has disperesed, chuck in a match it will ignite.
If you replace all the air ( oxygen) with an inert gas, ie argon, co2, nitrogen it wont ignite either as the oxygen has been removed, no matter how much gas is left in there.
Dont forget too some gasses are heavier than air others lighter, so this can effect if you have the bottle the right way up or not, when purging.
And yes people do die when they get this stuff wrong
Like I said earlier I do this for a living on a much larger scale. When I do one at home I remove the gas first but priming with warm water. As the water is more dense than the gas regardles of its state( liquid or gas phase) the gas comes out the top as the water goes in.
skotl
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Ahaha :P . It was really anti climatic
Kent
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OK I wasn't going to say it because as stated I am firmly against this practice. I did however used to work on various vessels that contained such fuels etc many moons ago. What we did is filled them up with either water or dry fine sand (obviously the latter is not much use if it's a fuel tank fix.
Still it contains enough chance of dropping a clanger that for the sake of rolling a cylinder I recommend it's not done
Still it contains enough chance of dropping a clanger that for the sake of rolling a cylinder I recommend it's not done
outofthefire
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If we all had the means to roll steel i'm sure we would, but most of us will never have a set of rolls and the cost of it compared to a free bottle is a no brainer. There is an element of danger in almost everything we do, you just have to minimise the risk and use common sense (which I realise is an oxymoron when it comes to cutting a gas bottle) in my opinion the end justifies the means.
rtbcomp
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One thing that might be worth considering. After removing the valve make sure all the LPG has boiled off before adding water, otherwise the boiling gas could freeze the water and trap the gas inside the ice. Applying a grinder, plasma cutter or gas axe could thaw the ice releasing the gas. You'd have gas, ignition and air all in the same place and an explosion would be the result.
Kent
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So many such unthought of risks in this hence my thoughts. Do enough of them and a miss hap is inevitable
brightspark
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I've used 8 as tanks and blast pots just take the valve out steam them out fill 3/4 full of water .drill the holes in and weld the bosses on and empty them out .no chance of any accident
slightly off topic, but just because you can smell something doesn't mean it will it will ignite.....
.... a few years ago,someone decided they didn't like my car so they stuck a rag in the filler pipe for the petrol tank on my car and lit it.....
..... just ended up with some charred paintwork and the car survived, and the tank had plenty of petrol in it.
when I weld the petrol tank up for my Herald, I'll be taking precautions though, as I think I was very lucky after the above incident.
.... a few years ago,someone decided they didn't like my car so they stuck a rag in the filler pipe for the petrol tank on my car and lit it.....
..... just ended up with some charred paintwork and the car survived, and the tank had plenty of petrol in it.
when I weld the petrol tank up for my Herald, I'll be taking precautions though, as I think I was very lucky after the above incident.
brightspark
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a full petrol tank is safer than a nearly empty one when a flame is near
Burdekin
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A old college welding teacher told me about how he use to weld full lorry diesel trailer tanks (the big tanks not the fuel tank).
