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Making an auxiliary air tank from an old LPG bottle.
tilly819 - 24/10/20 at 11:46 AM

Hi all,

Here are my latest efforts in the workshop. Seems to be working well so far. Not blown myself up anyway...

Hope you enjoy the video.

jacko - 24/10/20 at 03:31 PM

Nice work
Can I say why you would need a second tank or is it because you do spraying

Mr Whippy - 24/10/20 at 03:43 PM

Sounds a great idea tbh, they are really well made and often just lying about. I used one to make a very powerful underseal sprayer with terrific results and only cost a few pounds to make.

gremlin1234 - 24/10/20 at 07:52 PM

I saw the headline for this post, and thought of two things,
1: mount it so it drains.
2: paint it so it doesn't look like a propane tank
thankfully you did both

indykid - 24/10/20 at 08:44 PM

I've just done similar with a 47kg cylinder. I opted to weld a boss in the bottom as having filled the bottle with water to purge it, I found the boss for the valve protrudes into the cylinder and trapped water so it would never fully drain.

I see you've put a ball valve on to isolate the cylinder, but do you still have a pressure relief valve? The calor bottles have a 26bar PRV built into the valve body but as I've junked the original valve body, I've put a 10bar valve in a T to mitigate the risk of explosion in a fire. The bottle thread is 3/4 BSP should you want to use pipe fittings if you do another one.

How do you find the smell of the air after it's been in the propane bottle? I haven't used my 47kg cylinder in anger yet, but the 19kg one I did before still had enough stenchant in it to make the air smell bad for quite a while. I chucked some gravel in this big one and rolled it round the lawn for a bit so I'm hoping it's not quite so pungent.

v8kid - 25/10/20 at 03:08 PM

Nice Video as usual.

For others copying this project the thread in the propane tank is a standard BSPT thread and it costs only a couple of quid for a BSPT to compression adaptor from toolstation/screwfix and saves you a lot of machining plus having a larger bore. IIRC 22mm pipe has a higher burst pressure than 15mm. Also I find thread sealing fluid is more reliable than PTFE tape.

Is the polythene tube connector OK? I can't be arsed googling it but I guess you've done the homework.

In the past I used a similar technique to make a vacuum chamber to suck oil out of dry sump tanks - any other uses for old propane tanks apart from heaters that is


Simon - 26/10/20 at 11:05 PM

Just to state the obvious and ensure tank has (as in this case) been purged - we had a local chap kill himself a few years back trying to make a bbq from an oil drum/gas cylnder that exploded when he cut into it.