TargetTalk

Most you seasoned PCP guys already know this, but for the newly initiated guys here's a few notes on using a hand pump to fill your rifle cylinder. I am lucky to work where I can get an air tank filled any time I want to, but it still involves taking the tank to work and in and out of the plant to get it filled, so there's a minor hassle involved, but it's a great situation and I'm grateful for it.

BUT, I also wanted the option of being able to fill a rifle cylinder at home, so as to never be in a situation of no air. To that end I bought an FX pump in the classifieds, new never used. I currently have an Anschutz 2002CA that has a 215cc cylinder, which is usually good for anywhere from 1100 to 2900 psi and still give good shooting results (those are not exact numbers, but you get the idea). To fill a cylinder from 2000 psi to 2900 psi is pretty darn easy. This is the latest FX 3 stage pump, and I am 5' 9" and weigh 195#, and at 56yrs old, pumping, even at or near the 2900 psi limit is not hard at all. I pump slow and even strokes, and in maybe five minutes, take a break and let the pump cool, although it never feels anything more than lightly warm to the touch. I believe it's the innards that are getting hotter, so I take a break, and it's an easy task. I had read all the posts about air pumps and was leery of using one, but it's no big deal at all. I can fill the Annie cylinder in two sessions of five minutes easily. The thing to remember is that the down stroke is easy except for the last five inches or so, and that's where the pump does it's business, and still, it's nothing to be excited over. It's not like you're doing aerobic exercise at all, it's just a steady, slow pumping with your weight doing the lion's share of the work at the very end of the stroke.

So all this is to say that you shouldn't be afraid of a hand pump, as long as you can jack up a car, or pump up a bicycle tire, it's not much more work that that. The design of the pump does the work for you mostly. Now, if you consider that a scuba/SCBA tank can be had for roughly the same price as a hand pump, and air fills are easy for you to obtain, then it's a better deal for sure, but not so much so that a hand pump is out of the question. The moisture problem, (if there is one), is something I've not been able to detect yet. From what I've read, it's more of an urban myth, than any actual facts that it can be detrimental to the gun. I suppose if you pumped up a cylinder in the heat of summer, when the humidity is high, it might be a problem, but that remains to be seen.

All I'm trying to say, in a lot of words, is that if you're new to this pcp thing, don't be afraid of a hand pump, it'll work fine. I've not gotten my hands on a Hill pump yet, but probably will at some point, and I hear they are the cadillac of pumps, but the FX is no Yugo either, it is well built, strong and efficient, so there's not much use to go looking for a pump right now.

Moisture is a real issue unless you have very dry air where you live. I drain my pump every time I use it, which is rarely because I have a scuba tank as well. Each time I get a small amount of water out of the bleed valve. Also ease of pumping is very relative, if like me you're of short stature then your weight isn't enough because you can't get over the pump enough for a full stroke with any ease.

Rob.

I'd be interested in hearing from someone who's actually had moisture problems from using a hand pump. I've looked around, and I'm not trying to be obstinate, but no one seems to have actually had the problem, just heard about it.

bchannell wrote:I'd be interested in hearing from someone who's actually had moisture problems from using a hand pump. I've looked around, and I'm not trying to be obstinate, but no one seems to have actually had the problem, just heard about it.

What you mean apart from the problem I mentioned above ? I'm sure it's not a problem that will cause cylinder malfunction any time soon, but I'd rather not put moisture into a cylinder if I don't have to as it will lead to corrosion.

Rob.

There are several types of pumps, some are easy to use others not. This explains the different experience of different people.

So it is a matter of choosing the right pump

But one problem (in Europe at least) is that one of the most common brand is Gehmann but Gehmann is not a manufacturer, they buy their product from other companies and there are types models of Gehmann pumps not clearly identified by a type or model number/name. So it is pretty difficult to know what Gehmann model you have or will have especially if you buy it online.

About moisture, I always opened the bleed valve but never had anything coming out, I guess it really depends from were you live ?

Well, I have this to say about pumps and tanks. I have a LOT of diving kit including half a dozen tanks lying about, but I bought a Hills Pump. I bought the complete rebuild kit from Hills direct and their service support was terrific and the correctly identified the pump before sending the parts and they all fit fine first time.
The pump I bought had been a bit abused before I bought it but they are so well made that it repaired easily and cleaned up great before the rebuild.
So. Do I get one of the tanks tested and filled or do I use the pump?
Well, couple of years ago I had my first heart scare, so I use the pump. The dastardly instrument of torture that it is!
Not really, I shoot because my mind tells me it is a healthy thing to do, good for mind good for body. The Hills pump is a great piece of kit and although I do procrastinate some days I just know that really the excercise IS good for me.
So, I use a pump and it is easy to use and it gives me some much needed excercise. And I get to shoot guns. What's not to like?

Moisture. Moisture is generally a problem in most metal vessels not designed to hold it. If you introduce moisture to a pressure vessel the problem is exacerbated because the moisture is under pressure now. It is a good idea to take as many precautions as possible to prevent the ingress of moisture.

Some more info:
Pumping is no great challenge.
I've got both a Hills and an FX, the effort is about the same.
The Hills appears a bit more solid.
I haven't tried the newest FX; it appears to have a "kinder gear" for those who find the final high pressure tough.

The Gehman and Anschutz pumps that I've seen, are rebadged FX pumps. I've got one of those "Benjamin" pumps from the uS; no good...

Crosman is developing a contraption that is just around the corner.
In theory this seems promising, if the basic quality is OK.
Looks really ugly...

Divers tank is much easier, and the air is drier.
Nice to have a pump anyway........

Here is a quick back-of-the-envelope calculation of how much water might be inserted into a cyclinder on a fill.

Lets assume the 215 cc cylinder is empty.
Lets assume we pump it up to 3000 psi. This is 200 atmospheres (200x15psi=3000)
Lets ssume the temp is 20 deg C (about 72F) and 50% releative humidity.

So the amount of atmospheric air that is pumped into the cylinder is:

215x200= 43,000 cc (43 litres)
A cubic metre is 100x100x100 = 1,000,000 cc (1000 litres)

This means the 43,000 cc is equal to 43,000/1,000,000 = 0.034 cubic metres.

The amount of water in a cubic metre at 20 deg C and 50% rh is about 8 grams.

So now we can calculate how much water gets injected into the cylinder:

0.043 x 8 = 0.344 grams (about 1/6 ounces)

There is no doubt that if all the moisture and air gets all tranferred into the cylinder, the moisture will condense inside the cylinder. It appears to be not much but I suspect that all the water is not dumped as you use it, therefore, everytime you refill or top it up more moisture will be inserted.

So if you just top up the cyclinder then less moisture gets inserted.

However...........it would be prudent to drain the cyclinder every so often or at least check it for water. To test this hold the cylinder upside down with the air release fitting fitted. Give the water time to drain to the bottom - and give the air release a quick squirt. Any moisture should show itself by spraying out

If the pump has an inlet hole then I would suggest getting hold of some silica gel in a tube and suck the air into the pump though the gel. That will leave about 1% of the water in the air before it gets compressed and will limit the moisture issue.

The gel will need to be heated overnight at about 105 deg C to dry it sufficiently to ensure the moisture is eliminated. Most powered pumps have a drier. But I have no idea how often the drier is reconditioned. It needs to be!!

Keep the gel sealed from the air when it is not being used.

I also think that moisture could be one of the reasons the ISSF have limited the lifetime of a cylinder to 10 years.

Moisture = corrosion = premature failure.

I used a hand pump for my Anschutz 202CA for years. We live in an area that has a pretty good rain fall so the humidity is on the high side. I always had condensation in my pump. I never experienced any issues with the rifle and I sold it on this board. I did however see SSP rifle pictures showing severe corrosion from water vapor. I may have seen the pictures here. As I recall this particular model had materiels that we especially prone to corrosion, then those parts were changed / upgraded to prevent this problem. So those pictures really scared me. A new rifle is a 2000 - 3500 dollar investment and I did not want to damage it or have to send it in for repair. I think all the major airgun manufacturers prohibit the use if hand pumps. So when I bought a new Anschutz 9003 I also bought a 700 dollar air tank. I am also lucky because the university that I work at has a diving club and I can get unlimited fills for 25 per year. So while I never had any issue with the hand pump, I know for a fact that it puts moisture into the rifle, and that is not covered under warranty. This may cause problems and leave me without a rifle for an extended period of time. Since I can get the 4500 psi cylinder filled it was easy to spend the 700 dollars on a tank. Compared to rimfire ammo a 700 dollar tank and 100 dollar/ 5000 round of pellets is cheap. I see the hand pump verses the tank as a pay me now or pay me later proposition. A tank is cheap insurance against water damage. One tank will give something like 10,000 rounds so it is not a big issue getting fills. I think a 700 dollar tank may be cheaper than a 300 dollar hand pump if a shooter considers voiding the warranty and the potential for accelerated repair.

No, not all major manufacturer prohibit the use of hand pump.

Steyr and Asnchutz allow the use of hand pump (from the user manual of the LP10 and Lp@).

Feinwerkbau says "We do not recommend to use hand
pumps."(from the user manual of the P44). Now what means "not recommend" for me, it means that it isn't recommended but also not prohibited (note that the text in German = original text I guess since FWB is a German company and the French translation use the same word = recommend, not prohibit) ?

That said, I actually took the same decision as you did: when I bought a second LP10, I decided to mainly use a big compressed air bottle because even if moisture isn't supposed to damage, dry air surely won't damage.

I thought Anschutz explicitly forbid hand pumps so I gave a brief look at their web page. I found this disclaimer in the 9003 manual:

Only.refilling.bottles.with.a.maximum.pressure.. of.200.bar.may.be.used!
Only.oil-.and.water-free.compressed.air.. may.be.used.(DIN.EN.12021)!
Filling.of.the.compressed.air.cylinders.may.only.be. carried.out.using.the.genuine.ANSCHÜTZ.refilling. adapter.(Item.No.:.001521)!
ANSCHÜTZ.recommends.the.use.of.diving.bottles.. for.refilling.the.compressed.air.cylinders.


DIN en 12021 is the purity spec and the spec applies to multiple stage compressors as used in scuba shops. I doubt a hand pump could meet the same dryness as a multiple stage unit. I looked up the spec, but it looks like you have to buy PDF files, so I quit looking. So I will make the wild assertion that Anschutz requires super dry air that a hand pump can not deliver. I could easily be wrong on that.

Qualitatively, I have a Bauer 4500 PSI compressor. It puts out water by the cup. It has 3 stages and a huge final water filter. My compressor meets the oil free / dryness spec DIN en 12021.

So as a funny side story, I did not buy the 4000 dollar Bauer Oceana to save on 25 dollar annual fills or the fear of water in a hand pump. I bought it for 1200 on a fire sale, and I thought that was a good investment. I'll probably use it for a long time and sell it for way more than I paid.