High pressure air pump

Edited By John Wood1 on 02/07/2010 16:27:28

With my old Webley Axsor I bought a hand pump. It was about £40. To make one you would need about 600-700 mm of 25-35mm thick wall hydraulic tube. You will have to design the top guide, piston and valves your self. The pump shaft is 12-14mm solid rod and the ‘T’ handle is equally rugged. The bottom of the pump with the foot rests was also steel, with a 250 bar pressure gauge and had a ‘blow down’ valve to depressurise the system and get the gun off.

To use the pump you kept your back and arms straight and bent your knees letting your body weight do the work.

Edited By Richard Parsons on 03/07/2010 11:36:41

Hi John,

The pump its self was rather like the old fashioned motor car type tire pump but much more solidly built. There was a simple water trap in the base of the pump and an in line filter.

The piston was sealed to the cylinder walls by ‘O’ rings and moved on the pump shaft closing off the inlet valve closing it against an ‘O’ ring.

The filler valve on the gun’s air chamber was sealed by two loose O rings which were compressed by air pressure.

I think it could be made in the normal workshop for about £40 or less, but I do not think you could do it with a mini-lathe.

Regards

Dick

Edited By Richard Parsons on 08/07/2010 12:15:41

Hiya Geoff, I am about to start making a new PCP hand pump which will be fitted mechanically to pump HPA to fill my airguns instead of all that heaving and sweating. (In this weather).

If you google or use You Tube to ask 'How to build a PCP pump' you will see at least two designs that fill air rifles or scuba tanks.

Not pretty but they will do the job. John is correct HPA is dangerous but so is electricity, so like most things in a workshop, carelessness can get you hurt or worse. Safety is the responsibility of every engineer no matter what level they work at.

I suggest you have a look at the hand pumps available on the market. Hills or FX are reported to be good and expensive too. The tube is fairly easy to find and the seals. You can build one fairly easily and material like 'High pressure hoses' are not expensive unless you buy them from a gun shop. (No offense John but I find the prices in the airgun industry to be a complete rip off).

You only have to look at the HPA gauges the like of AA or FX put in their air rifles, they are basically expensive inaccurate crap. You don't have to believe me, just look on You Tube about how to replace one of their gauges and you will see for yourself the kind of expensive crap they foist on us.

So Geoff you can build a hand pump and with a little thought can turn it into a mechanical compressed air filler, not a huge compressor and it must be watched but it can be done Geoff and with a mini lathe too. In fact Geoff I no longer buy my airguns from the 'Cartel' but make my own. Courtesy of Mr H. M. Buckley and his book 'The Modern Pneumatic Airgun'. The only thing I don't make are the rifled barrels but there are plenty of spare used barrels knocking about.

HTH. Mike

I never ever needed a book to make a total one off air rifle down to each screw, big difference and still lead the way 24 years on after learning the hard way. Anyone can copy what they cant do is figure it out.

The Buckley book is based on 30 year outdated primitive stuff ie the Rentokil Daystates from mid 80's.

What no ones mentioned is rated pressure ie up to 200bar should withstand 300bar or better. Not even certain manufactured air rifles do that some blow at 235bar. There are some that can be topped up to 300bar ie Ripley and old Walther LG200/300 but reg will pack up.
Heres a 200bar cylinder I didn't expect to take 300bar, and the gauges are inaccurate. **LINK**

To even make a pump it will set you back not only in materials £40? but guage £7 to £70, hose £25 and quick fills £20+ and wont be too much short of buying from a shop around £140 tested and made for the purpose. Even then face the constant music of dispersing hot air on to filler valve and burning out. Even seen knock open valves burn due to using pumps because of the short bursts of air creating heat more than from a dive bottle. Forget whats its called but the prototype electric Daystates used tell you the temp within tube.

There are high pressure compressors petrol, diesel and electric non cheaper than around £1350 fo r intended minimal use.

Buy a bottle and be done with it £4 to £6 a fill costs more in wear and tare getting there. Luckily must be 12 within 20 mile.