Increasing Capacity With Old Gas Cylinder

[Onoff]

I've been told I can up the capacity of say a cheap 24L air compressor by attaching a big, empty, propane type cylinder. Is this done often and are there any do's or don'ts on the subject?

Cheers

 

[Wildefalcon]

Be careful, old gas cylinders contain residual gas, which does like to explode. Fuel air bomb. Google it. But, given due care, can be done.

 

[123hotchef]

go for it I have a few on the go 2 in the garage and one under my 4x4 ur compressor will work harder to fill it though so be wary of the duty cycle.

 

[delta9]

Planning on doing the exact same thing, already collected one ☺ I think the hardest part is getting the valve off, I got one off before but it was a smaller butane bottle, the valve on this 47kg big bottle is tight, I've ordered big stilsons to hopefully remove it!

thinking of joining 3 x the 47kg bottles together, which should give approx 270L of compressed air.

Other than the inlet/outlet I would fit 2 x pressure relief valves in case one fails?

 

[Paul G]

I have a compressor with a small tank. I have an old tank, twice as big from a compressor that broke its crank, linked to the smaller one via an on/off valve.

Lets take my sheet nibbler (toe nail cuttings type) as an example:-

16g ally with the smaller tank cuts 500mm and then takes 1 minute to re-fill.
With the larger tank attached, now 3 times the volume, it will cut 1000mm and take 3 minutes to re-fill.

A re-fill is from when the nibbler stops @ 65psi to 120psi.

So twice as much cutting with three times the wait to fill up.

If all you wish to do is, i.e. blow the dirt from a thread, then a quick fill is better.
The size of the tank is nothing to do with the power of the compressor. What is the ultimate is bigger motor and higher CFM.


Another example is my nut runner. It will undo 5 wheel nuts and be back up to pressure by the time I've moved to the next wheel.
Just about perfect for me, although when this one gives up I will look for a bigger CFM. ( or whatever it is in metric )

HTH
Paul G

 

[Turbo]

A 24l compressor will struggle to feed 3x47kg cylinders. I had 2x24l compressors feeding one 47kg cylinder & initially you have plenty of air but using air hungry tools like a die grinder or sander you will still run out of air & it will take ages for it to build back up again. One of my compressors would eventually cut out on the motor thermistor due to it running flat out for so long it was overheating!
A 47kg cylinder looks like roughly the size of a 100l tank so you are asking the same pump to feed a tank 4x the size it was designed for. I now have a larger 200l compressor & it can feed all my tools no problem & so much quieter!

The one advantage of having the larger tank attached is that it gives the air a better chance of cooling down & loosing more moisture from it. I had my tank mounted on its side & welded a bsp fitting into the bottom so I could fit a ball valve for draining the tank. I had another fitting welded to the side for an inlet & the outlet was from the original gas fitting.

I could be wrong but the brass gas fitting could be a left hand thread like most fuel gas fittings.

 

[Turbo]

I opened the valve & let it vent for a few weeks before filling with soapy water & leaving for another few weeks.

 

[123hotchef]

I have a compressor with a small tank. I have an old tank, twice as big from a compressor that broke its crank, linked to the smaller one via an on/off valve.

Lets take my sheet nibbler (toe nail cuttings type) as an example:-

16g ally with the smaller tank cuts 500mm and then takes 1 minute to re-fill.
With the larger tank attached, now 3 times the volume, it will cut 1000mm and take 3 minutes to re-fill.

A re-fill is from when the nibbler stops @ 65psi to 120psi.

So twice as much cutting with three times the wait to fill up.

If all you wish to do is, i.e. blow the dirt from a thread, then a quick fill is better.
The size of the tank is nothing to do with the power of the compressor. What is the ultimate is bigger motor and higher CFM.


Another example is my nut runner. It will undo 5 wheel nuts and be back up to pressure by the time I've moved to the next wheel.
Just about perfect for me, although when this one gives up I will look for a bigger CFM. ( or whatever it is in metric )

HTH
Paul G

Just a clout with a hammer and chisel sends them flying

 

[sasquar]

I think the hardest part is getting the valve off, I got one off before but it was a smaller butane bottle, the valve on this 47kg big bottle is tight, I've ordered big stilsons to hopefully remove it!

obviously, being the good boy that I am, i wouldnt have any first hand experience of repurposing gas bottles, but if i needed to remove a valve from a 47kg bottle, i wouldnt be using stilsons at all, you just wont be able to hold the bottle tightly enough to exert the pressure you need to get the valve to move. What I would do, is to get a decent size club hammer, and a long (12"ish) bit of solid bar, and use that a chisel to get it moving. (im told) theyre tapered valves, so once its moving (which could take a couple of big hits) then it comes undone really easily..... Should only take a couple of minutes....

 

[brightspark]

just bat the valve on its side with a big hammer and it will remove it providing the ring collar is removed and u get the hammer in . works every time

 

[daleyd]

You can hold the bottle perfectly with a bar, some rope and a bit of rubber (like a section of inner tube).

I just lay the bottle on its side and put a length of bar through the collar, wedged against the ground - stood on the stillsons and valve loosened no probs.

 

[sg66]

Yup what he said more than enough places to hold the bottle at the top.

 

[postie jon]

i ratchet strapped mine onto a scaffold board