Making Planters from an old gas cylinder...

As a disclaimer to this post, strictly speaking even old and abandoned fuel gas cylinders still belong to the company that issued them - when you buy the gas, you're only renting the cylinder which is why there's usually a hefty deposit the first time around and then you swap like-for-like with full bottles when they're empty, and only pay for the contents.   Despite this, there's still a ready market for empty gas cylinders (just search on eBay, for instance) but perhaps their general sale may be outlawed in the future, as has happened with beer kegs.  However, there will still be damaged cylinders out there that would otherwise be condemned if they're beyond economic repair.

And on a safety note, never attempt to cut a cylinder unless you're 100% sure it's unpressurised, completely empty of gas and has been adequately purged !   Note that if you fully open the valve and leave it open with the cylinder upright, after an initial escape under pressure it will still remain full of gas at atmospheric pressure because these fuel gases are heavier than air and therefore can't escape upwards - the cylinder would need to be inverted to empty it of gas.  If in any doubt at all, unscrew and remove the valve adaptor altogether and then fill the cylinder to overflowing with water from a hose, leave it full for an hour, tip it up and empty it, and then leave it standing upside down for a few days.


Anyway, lecture over and back to the post....

We're always on the lookout for garden planters, and this autumn we'd bought two rhododendron bushes of varieties Rasputin and Golden Torch for which we wanted to find a permanent home before the cold weather really starts to bite.  These evergreen shrubs need acidic soil to thrive, which we don't have in the garden here, and so they're better off in pots filled with ericaceous compost.  The planters themselves must be large enough for the shrub roots to grow into over many years, and also heavy enough so they won't get blown over in the wind.

I regularly search on eBay to see what's available locally on a secondhand basis, using keywords such as barrels, urns, planters, drums, pots, tubs, bins, cauldrons etc, but it's difficult to find anything pleasing for a reasonable price, i.e. next to nothing !  

However, I remembered there was a damaged 47 kg propane gas cylinder lying behind the shed, just accumulating snails...  I'd tried to chuck it out in a skip once, but the driver said he couldn't take it.

So I heaved it out, measured it up and in spite of the damage (a crease in the centre), I decided I could still make two 40 litre planters from it.  It's around 375 mm in diameter, and I cut around the cylinder with an angle grinder in two places to remove the damaged section and make two half shells of around 400 mm in height.  

the cut cylinder...

I also cut off the valve guard shroud at the top end of the cylinder, because this wasn't quite big enough to make a stable base for the planter.  The cut edges were then all dressed, and large drain holes drilled in the ends.

drain holes drilled....

The one on the right above is from the bottom end of the cylinder and already has a base skirt welded to it, so it was basically finished and ready for a coat of paint, but the left one needed something added to make it stand upright on the dished end (the technical term for the shape is 'torispherical').  So I thought, "balls" !

The idea was to somehow fix three balls to the base, to make a tripod stand.  I first thought of using golf balls, because I've loads of them already, but a slightly bigger size would be more in proportion with the cylinder.

I reckoned that 2" (50.8 mm) diameter snooker or pool balls would do the job, the only problem being where to get hold of them.   Amazingly, eBay had quite a few choices of used balls, although I wanted three exactly the same and the cheapest way to achieve that was actually to buy a full box of 16 pool balls, brand new.  

a load of balls....

Apparently, these are sold to pubs and clubs etc so they can replace those balls that are nicked by the patrons !   For reasons unknown, a box of blue No 2 pool balls was the cheapest option at less than £8 delivered and, as luck would have it, light blue is the colour of the tin of Hammerite I had for painting up the planters.

I filed a flat on each of the three balls, exactly over the white spot containing the numbering, and then drilled and tapped the balls with an M8 thread.

After initial painting of the shells, I used short screws through the dished end to secure the balls, after first coating the threads with locking fluid to prevent them from working loose, because the screw heads will not be easily accessible when the planter's full of soil...

Finally, the planters were prettied-up using the dregs of an old tin of contrasting Hammerite paint, this one a deeper blue.   The graphics were added using stencils cut from paper after printing with free clipart images from the internet.

They'll be ready for planting up after a few more days inside the warmth of the workshop, to allow the paint to harden off and fully cure.


Update 22-Nov-16

Now out in the garden with plants....