PCP Compressors as used to fill Pre Charged Pneumatic air rifles.

Compressor for PCP

PCP Compressor Review and Maintenance Tips

PCP Compressor Review and Tips.

Setting up your own PCP Compressor correctly will prolong the longevity of this great little High-Pressure PCP Compressor that we take for granted to fill our PCP air rifles. This PCP Compressor has the words Yong Heng Air Pump printed on the blue and sometimes black electric motor housing and comes in 4 models.

We import this PCP Compressor and perform a series of modifications and tests prior to releasing it for sale. Price at the time of writing this is $565.00 including GST, ready to connect and pump air with everything assembled and tested.

Setting up the PCP Compressor.

I am going to assume you have purchased your PCP Compressor from Gunroom in Brisbane and are about to connect it up. Firstly, the PCP Compressor has to be mounted LEVEL to the ground to ensure adequate lubrication from the ‘splash fed oil system’ they employ in the PCP Compressor.

Failure to do this may result in the Compressor overheating and possibly suffering piston or bearing damage from under lubrication. Check the oil level is correct.

 

PCP Compressor top view.

High-Pressure PCP Compressor

Overfilling the crankcase with oil may also result in the PCP Compressor dieseling: that is where oil bypasses the rings and ignites, causing the PCP Compressor to enter a ‘runaway mode’: this is where the Compressor actually runs on the bypass oil and the RPMs go through the roof until it breaks a con rod or something similar. Generally, the PCP Compressor disintegrates through over-revving.

 

Nulon Fully Synthetic Oil

Nulon Fully Synthetic Engine Oil 5 litres

 

Here is a note: I fill the oil in the PCP Compressor we sell with 5W-40W in Summer and 5W-30W in Winter, the oil is Fully Synthetic NULON. Do not mix it with mineral oil. Available at Repco and Cheap Auto Parts nationwide.

Next, you need to get a 30 or 40-litre container that has a lid, this stops bugs and what not drowning in the water and possibly blocking the small pump impellor (been there, done that). I recommend the clear plastic storage containers you get at BigW for around $12 when on special. Fit the pump by pressing it slightly on the bottom of the tank where the suction cups at each corner of the pump will hold it in place.

I then drill 2 x 10mm holes large enough to fit the 2 silicon hoses through them. You will need to remove the cable tie on the black plastic pipe fitting that goes into the pump outlet to get it through the 10mm hole. Then fit the silicone hose with the black plastic tube into the pump outlet socket after fitting a replacement cable tie.

The return hose has to stick through the lid by no more than 40mm, so it is clear of the water. On my tank lid I used Sikaflex to bond the silicone hoses in place on the plastic lid – silicone may work as well as Sika as it is 1/4 the price so I would try that first. Let the fittings and silicone cure overnight.

When you connect the power to the PCP Compressor, the pump should automatically start running providing you have plugged the pump cable into the compressor side. To help you see that water is circulating, I put a small bottle of food dye (red or blue) into the water. You can view the water circulating in the image below.

 

PCP Compressor water cooling tank

Dyed Water cooling flowing through a PCP Compressor

Should the pump stop working while the PCP Compressor is running, the water will run back providing the return pipe is above the water. That way, should you see clear silicon hoses (without the food dye running through them), you will immediately know the pump is not working and shut down the PCP Compressor. This is demonstrated in the following image.

 

 

Dyed water cooling system in PCP Compressor

Water cooling not running to the PCP Compressor.

 

The PCP Compressor will overheat very quickly without water cooling. Trust me here…

 

Felt pad on PCP Compressor pipe.

Felt rubbing pad on hot pressure pipe.

Note: You will see I put felt with 3 cable ties on the top PCP Compressor air pipe, that is not for looks, it is to save you from burning your arm when you reach over to dump the air. You can thank me another day.

On a cool day the PCP Compressor will top up a Brocock Compatto PCP tank from 50 Bar to 200 Bar in 40 seconds, so don’t walk away and leave the unit running. While these PCP Compressors are reliable, they should not be left alone if you believe in Murphy’s law.

I am often asked if they can fill a Scuba tank. The answer is yes, providing you have adequate water in the reservoir, a MINIMUM of 40 litres. Any less and the water will quickly heat sending the PCP Compressor temperature into the red (by Red, I mean in excess of 80 degrees).

Should the temp get up close to 80 degrees, just shut the PCP Compressor down and leave the pump running to pull down the head temperature of the PCP Compressor. Make sure you close off the Scuba tank and drop the air in the filling hose.

Note: Do NOT put ice in the water as some clowns do. The sudden cooling in the water jacket may pinch the final stage piston that gets really hot, then you will have problems.

The PCP Compressor Water Filter.

The filter supplied with the PCP Compressor, is in my opinion, too small for repeated fills, used in high humidity or left in place over repeated fills. It comes with small foam filters that are not really that efficient as they quickly fill with moisture. Further to that, they are expensive to buy if you can find a supplier.

The alternative? Meds, and I am not kidding you. These tampons are designed to trap moisture, they come with a string for removing them out of the filter housing (as well) and above all, they are plentiful and cheap. For those of you unfamiliar with tampons, Yes, you have to remove the plastic covers first…

The image below shows the replacement filters and the tampons for those of you who have lived under a rock for decades. Woolworths sell them for less than $5 for a pack of 8 with Chemists Warehouse selling a pack of 30 or more, for just a couple of bucks more.

Now at first glance, they may seem a bit thin, but don’t be fooled, they swell up with the first hint of moisture and you need the attached string to remove them. I use the Carefree SUPER (?) Tampons below and they work just fine for the heavy use my compressor gets.

 

Tampons used as compressor filter elements.

Filter inserts on left of tampons used as filter inserts.

 

Water is the enemy of PCPs and the filter is the only thing between your rifle getting rust in the action and/or the regulator and this PCP compressor. I advocate using a larger filter such as the one depicted below that comes with an extension whip hose making it easy to use.

However, if you are budget wise and only have the small filter that came with the compressor, use the tampons, change them regularly and you will be OK. The key words here are, “change them regularly…”, which is a pittance in cost to the damage water can do to your PCP. If you had a Daystate PCP, would you risk getting water in it? Of course not, so change the filters regularly.

 

Large water filter for PCP Compressor

High-Pressure water trapping compressor filter and extension whip hose

 

Tip: When draining the air from between the compressor and the PCP, dump the air FAST. This helps seat the non-return valve in the PCP cylinder due to a high-pressure differential. If you dribble about and let the air out slowly, occasionally you will get the valve being held open slightly by the through-passage of high-pressure air, draining your cylinder over a few minutes to a few hours.

Tip: Always leave both drain valves on the compressor OPEN when not in use. This allows any resident moisture to drain out or dry up.

Tip: You should dump air from the High-Pressure drain first and before the air is completely exhausted, then open the Low-Pressure drain next.

PCP Compressor Safety.

Not to put too much emphasis on safety guys, but this little compressor can pump to 4500psi (300 Bar) in no time at all, so ensure that any cylinders on PCP guns are within their ‘use by date’. 300 Bar cylinders mostly use a final date after which the cylinder must be thrown out and not be retested.

Having owned a Dive Shop in Port Hedland around 100 years ago, I am all too familiar with high-pressure air cylinders and resulting accidents due to complacency.

The compressor has a burst disc that goes off at around 4500+ psi but that won’t save you should you put 4500 psi (300 Bar) in a 200 Bar cylinder or a cylinder that is dodgy. I will be doing a full article on PCP Compressor safety shortly and it will include images designed to disturb you so as to let the realisation of high-pressure air danger sink in.

PCP Compressors for your pneumatic air rifles.

Electric PCP Compressors for filling your pneumatic air rifles are steadily gaining traction amongst air rifle enthusiasts Australia wide. With the prices that are lower than Carbon wrapped Scuba bottles in some cases, it is a no-brainer to opt for an electric high-pressure compressor for your PCP.

In this article I will lay bare the pros and cons associated with buying one of the Chinese compressors and what I would expect you to get from the experience. I will discuss only one model here, but you can apply most of what I will show you to other small PCP compressors. Note: when I talk about small PCP Chinese compressors, I am referring to the units that you can buy direct from China for under $500 – believe it or not, the freight costs more than the compressors.

Hand Pump close up

Hand Pump

Hand Pumps and Scuba Bottles.

Going back a few years, if you had a PCP (aka Pre-Charged-Pneumatic air rifle), you had to charge the air rifle reservoir with either a hand stirrup pump costing $300 – $450 or decant the air from a Scuba bottle.

The hand pump was and still is the hard way of doing anything, I even get a sweat looking at one. Constant use of the Hand Pump and you will find you have muscles where you would least expect them. The leading hand pump several years ago was the Hills pump out of the UK, but it has recently been eclipsed by Chinese hand pumps at as low as 1/6th the price of the British unit. Of course, there are those of you who will say, “I would prefer to buy British as they are better than the Chinese models”. Well that is debateable, but if I had to revert to a hand pump, I would rather buy 6 units for the same money as 1 UK hand pump. Having worked on both the British and Chinese hand pumps, I will say this, there is very little to choose between them now.

Next option was the Scuba bottle in either 232 Bar or 300 Bar. The 232 Bar is the most accessible Scuba bottle second hand and priced anywhere from $50 upwards. The problem with these 232 Bar tanks is that most PCP air rifles now run on 240 Bar and hence you don’t have the pressure to fill one to capacity. The 300 Bar tanks are a lot more suitable, offering quite a few fills dependent on volume but these bottles cost a heap more than the 232 bottles do.

Cons:

  • Bottom line guys, you cannot put more air pressure into your PCP than is in the Scuba bottle,
  • you are tied to the mercy of a Dive Shop for filling,
  • many dive shops do not have the capacity to fill to 300 Bar,
  • there are not too many dive shops out in the country,
  • there are the costs of filling and having the bottle tested regularly,
  • the aluminium and steel scuba bottles are heavy while the carbon wrapped bottles are light but very expensive.

Pros:

  • The Scuba bottles are very portable and suitable for trips to your club or to go hunting.

High Pressure PCP Compressors, are they really the answer?

As PCP air rifles require air pressures ranging from 200 Bar (2,940 psi) to 300 Bar (4,410 psi) you need a 3 or 4 stage compressor to attain that degree of air pressure. That is where we get the term High Pressure Compressor from when discussing filling Scuba bottles or PCP air rifles.

For this article I am staying with the Chinese PCP Compressors pictured and am in no way referring to the likes of (say) Bauer High Pressure Compressors as the two are worlds apart in performance, cost, duty cycle and longevity. Having owned a Dive Shop for years when I lived in Port Hedland, I owned 2 Bauer Compressors for filling Scuba bottles where we filled hundreds of bottles a month in the heat and humidity. I have a fair idea what I am about with High Pressure Compressors as we apply them to PCP air rifles.

Cons:

  • With the electric compressors you need 240 volts and that is not always going to be available when hunting or when visiting small bush shooting clubs,
  • You need at least 20 but preferably 40 litres of cool clean water to cool the compressor,
  • These Chinese units do not have a very high duty cycle, in fact I would NOT recommend running one continuously for more than 30 minutes,
  • The water trap is hardly what I would call a trap, having an absorbent filter no bigger than a tampon, (did I say that?….)
  • You cannot walk away and just leave the compressor running (as I will explain later).

The Pros:

  • No driving to and from a dive shop getting your Scuba bottle filled, you can now fill at home,
  • Running costs are negligible,
  • Fairly portable providing you can source 240 volts and water,
  • Cheap.

Buying from China direct.

Those of you who want one of these Chinese High-Pressure PCP Compressors can buy direct, paying anything from $460 to $700 depending where you source one from. The gamble you take is warranty, as there are NO compressor agents in Australia that I know of and given the nett price of the compressors (excluding freight), finding someone who can repair it for less than a new one would be difficult. I wish you luck.

I am bringing them in with bulk buys, marketing to my PCP customers of Gunroom only as I am not making a profit and only providing a service by supporting customers that support me. The compressors cost me $460 landed here, I then must pay 10% GST, $20 for synthetic oil, pull the compressor down and do 3 modifications and then test them. The $50 that I put on each compressor taking the retail to $580 including GST, barely covers my time making the modifications and on top of that, I must warranty the units. So, you see I am hard pressed risk wise with warranty and so this compressor is only available in a package price with a rifle or direct to a customer who has purchased one of my air rifles previously.

PCP Compressor strip-down

Modifying The Compressor

To understand warranty with regards to firearms and the like, we only get the faulty parts replaced and must pay the freight (chargeable to the customer) and do the labour at our cost. Yup, that is correct, we need to factor in our anticipated labour costs into the margin.

Running these PCP Compressors.

I have said this already, but I cannot stress it enough, do NOT run the compressor for more than 30 minutes at a time. You must also dip your hand into the water tank and check the temperature regularly as these PCP compressors will get quite warm and become less efficient in hot weather.

With the humidity we get in places like Queensland, regular draining of both drain points is highly recommended while running the compressor. I leave these drains open when I have finished using my compressor to allow complete draining of moisture.

Do NOT attempt to fill a Scuba bottle with one of these small PCP compressors, they are not made for it. What I do, is I fill the rifle to be tested and that takes anywhere from 40 to 90 seconds depending on the residual air in the PCP if any, the outside air temperature, humidity, water temperature and air surrounding the compressor. I fill/top up the gun and then switch the compressed air valve over to my 300 Bar Scuba bottle which I run for 10 to 15 minutes or until the water starts getting hot. I do not allow the compressor to get over 75 degrees in head temperature: this is visible on the temp gauge beside the lifting handle.

Huma External Regulator

After filling around 10 PCPs over 2-3 days and adding 10-15 minutes of run time onto my 300 Bar tank, it is then full and can be used for quick fills should the need arise. I mainly use the 300 Bar tank to supply air at a regulated 240 bar air supply via a Huma regulator (inset) and a 2.5 metre whip lead plugged directly into a PCP for pellet testing at a set pressure for tuning air rifles.

So, should you buy one of the Chinese PCP Compressors for your PCP air rifle, I feel you will be very pleased with the purchase providing you follow my tips and try not to re-invent the wheel with the unit.

I have recorded the following fill times for your interest:

  • Brocock Compatto filled to 240 Bar from empty took 75 seconds, and from 50 Bar to 240 Bar took 45 seconds.
  • Brocock Bantam HiLite from empty to 240 Bar took 130 seconds.
  • Weihrauch HW110 from empty to 200 Bar took 58 seconds.
Brocock Bantam HiLite

Brocock Bantam HiLite

Running the compressor on concrete in the glaring heat of the day will provide longer fill times, while running in cool to wintry conditions will reduce filling times. Remember to keep an eye on the water temperature as this also affects the fill times. Do not walk away from the compressor while it is running as the water pump is only a fish pond centrifugal plastic unit and sure as shooting it will malfunction if you are not there to keep an eye on it.

Some guys are putting in ice to cool the water, well, if you do this you risk very chilly water hitting a very hot head and prompting damage to occur. I am not saying don’t put ice in the water to cool it, that’s ok in moderation like everything, but knowing some of the clowns that I know, they will overstep the mark for sure… Keep the water cool but making it cold on a sweltering day is not recommended. I can also supply a temperature gauge for the tank water should you want one.

As the air filter is basically non-existent, I am hopeful of sourcing a larger unit that can be retro fitted to the compressor for better filtration. Long whip leads, Foster fittings, BSPP adaptors and fittings are available ex-stock to suit these PCP Compressors.