Lidl Hand-Held Compressor + Aluminium Beer Keg

[Blake's 7]

Hi all,

I see from their latest brochure that Lidl will be selling these shortly.


I have had an aluminium beer keg in my possession for the last number of years after finding it in a skip full of scrap metal and I'm wondering if it could be made into an air tank with the above compressor attached to it somehow?

Has anyone here attempted something like this already?

Looking forward to your feedback.

Thanks.

 

[anjum]

I've got one of those or something very similar.
Not good enough for anything else than pumping tyres up really, which it does really well....provided you have mains power.
If you attach it to a tank it will fill it but very slowly and I wouldn't expect the compressor to survive for long.

 

[ukracer]

And the beer would be off before you could drink it.

 

[pedrobedro]

That's for inflating tyres, balls and airbeds as shown in the illustration it will not supply the volume of air to be useful for much else.

 

[hotponyshoes]

Beer kegs are generally only rated for 50psi or so.
Gas bottles are a good for a lot more pressure!

You could make something semi useful with a big enough tank and enough time for that little compressor to fill it. Main problem is those little compressors overheat and melt if you run them for long so you would need a timer for it to come on for 5mins then off for 30mins.(guess) And you would need some sort of cut-off for when the tank gets up to pressure and maybe even an unloader valve so the compressor can start under load.

Construction of the air stuff could be fairly simple as you could just bolt a tyre valve into the tank for an inlet fitting.

For the time and money there are a lot of better options.
Guessing but you could probably use an old fridge compressor for example, will still take ages but much better duty cycle.
Or a car air-con pump and a washing machine motor

 

[hotponyshoes]

There are not any flat surfaces on a beer keg.
You would have to weld the fittings onto it or have a threaded adaptor custom made

 

[dyno-tron]

The main challenge with this (as mentioned above) is that the compressor will overheat before it fills up the tank. It might not die immediately but it will have a very short lifespan due to a very small piston.
I used an old freezer compressor to do the same thing but with a gas bottle as the receiver, took a while to pump up but was virtually silent :-)

 

[Rig Pig]

Those little things are frustrating enough when you're pumping up a tyre at 30 ish psi, they take forever as others have said, don't bother!
My father in law has one of these from Lidel or Aldi, it's a good little machine.

 

[Seadog]

My father in law has one of these from Lidel or Aldi, it's a good little machine.

But noisy as hell.

 

[hotponyshoes]

To correct my earlier post, rather than a threaded adaptor you could just use a proper keg fitting.
If you could work out the plumbing it would be quick and easy to swap them over and you could build up a supply of loads of charged kegs.
But I still dont think 50psi is useful for much.

 

[Rig Pig]

But noisy as hell.

It's not quite but it works nicely, the little tyre compressors are noisy and ineffective.

 

[Screwdriver]

Well when I looked into it, I was happy to discover a beer keg would be good for 120-150psi.
Don't know exactly where that info is from so take it with a pinch of salt but I intend to build a small portable unit with one.

 

[Seadog]

Theirs went at 800psi

 

[hotponyshoes]

Maybe with a stainless steel keg but I would not fancy my chances with an aluminium one.
Even if it's not got any internal corrosion it's going to be riddled with microscopic fractures from years of chucking it about and at higher pressure cycle fatigue might be an issue.

Hydrostatic testing is relatively safe. 50psi of water is a slap across the face.
Air at 125psi blowing a 1mm bit of metal out is no face left and a good potion of skull missing.

 

[Parm]

It strongly recommend that you don't make an air tank with an aluminium beer keg

When it goes wrong you will have a lot of explaining to do and might even incur an unwanted holiday

 

[Screwdriver]

Maybe with a stainless steel keg but I would not fancy my chances with an aluminium one.
Even if it's not got any internal corrosion it's going to be riddled with microscopic fractures from years of chucking it about and at higher pressure cycle fatigue might be an issue.

Hydrostatic testing is relatively safe. 50psi of water is a slap across the face.
Air at 125psi blowing a 1mm bit of metal out is no face left and a good potion of skull missing.

Obviously I don't have any but if I did, they would all be stainless steel jobbies.

I am aware of the difference between springy air and solid water so if I make a little compressor, it will get a safety relief valve like a proper one.

I am more interested in building a vacuum chamber currently. Does anyone know the difference in rating between pressure and vacuum? I mean it is tempting to try one, if I had one

Back of my mind is a setup for vacuum forming where you pull a vacuum on a keg then use that to quickly suck a heated plastic sheet over the form. Don't know if speed is a good/bad thing for vacuum forming but I do know it cools down very quickly, often before the vacuum pump has done its job.

 

[hotponyshoes]

It's a good size volume tank for vacuum. You can only get to 1bar vacuum at the most. A 4bar keg 'should' be good for that and something collapsing is a lot better than something rapidly expanding.
But dont go creating black holes in the back garden.
The draw tube is about 3/4" bore but the common fittings are 1/2" or smaller. You could manifold more than one.

Under the right (wrong) conditions a faulty beer pump could pull full vacuum on a keg. They are mostly used in workplaces so I presume they have been tested to cope if it's a risk?

Ps, i am obviously only talking about the kegs you can buy legally. The type in the video above is about 125quid so might just be cheaper to buy the compressor..

 

[Milkybars]

It depends what you want the compressor for, I converted a small one like in @Rig Pig post. Bought one that was knackered (£20) on gumtree, stripped the motor of the tank and fitted a fridge/freezer compressor (degassed froma local shop).
I changed the oil in the fridge compressor, there are a few on-line tutorials/ you tube
This only used for blowing stuff down in the workshop and it's virtually silent. It's fine for the home shop.

Only thing I would say is pay close attention to the pipework, mine had a few different sizes and the compression fittings obviously need to be correct.
I put one of the cheap air/oil seperators on the outlet side.

It's hidden under a bench but has plenty of air flow around it

 

[Milkybars]

Pictures

 

[Hopefuldave]

Obviously I don't have any but if I did, they would all be stainless steel jobbies.

I am aware of the difference between springy air and solid water so if I make a little compressor, it will get a safety relief valve like a proper one.

I am more interested in building a vacuum chamber currently. Does anyone know the difference in rating between pressure and vacuum? I mean it is tempting to try one, if I had one

Back of my mind is a setup for vacuum forming where you pull a vacuum on a keg then use that to quickly suck a heated plastic sheet over the form. Don't know if speed is a good/bad thing for vacuum forming but I do know it cools down very quickly, often before the vacuum pump has done its job.

Vacuum can only get to a max of 14 psi - atmospheric pressure!
For vacuum forming you won't need a "hard vacuum", you're very unlikely to get better than 10-12 psi without an expensive pump, trying for a hard vacuum gets expensive as a lot of materials (particularly oils and sealants) will start to outgas and leaks are hard to spot - bubbles form inside leaks, not outside! A keg will be fine for vacuum that's achievable at what you can afford

Your empty keg will only pull its volume x vacuum, so if you start with e.g. 10 psi of vacuum, by the time you've pulled half its volume it'll be at a much softer vacuum, so based on a book my late uncle* gave me you'll want to do the initial pull with something like a hoover, close that off (big ball valve?) then hit it with the keg's harderer vacuum for Best Results - or the hoover may do it well enough?

If you're doing larger forms, standard practice in industry is to have an autoclave / oven around the form, could be as simple as a couple or tens of yards of nichrome wire in an insulated box and a PID temperature control (PIDs are a few quid from nice gents in China at the mo, and deliveries don't *appear* to be any slower than usual despite the Plague)

I use a lab-grade low-vacuum pump for bleeding hydraulics / emptying sumps, small vacuum formings like gauge lenses e.g. for my Trav-A-Dial) the vacuum vessel for that is a big glass mayo jar (lots of emptyings!) and it works ok, no clue how hard a vacuum it makes though, enough to have to release vacuum to unscrew the lid!

Dave H. (the other one)

* Uncle John had a business doing... vacuum forming and plastic coating, after demob from the early 50s through to the 70s - the book's "Practical Plastics" and sparked the idea for it, still have it somewhere, I hope!