A warning on Hill Mk 5 pumps

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LeadandAirFun

LeadandAirFun

Member
Oct 23, 2021
68
9
North Carolina, United States
Do not use one without the air drier! The outer tube is steel and will rust from condensation, found out the hard way and thought I would pass this on. Other than that its good quality, easier to pump and fills the gun quicker than the cheapos. Anyone know where I can find and exploded diagram or disassembly instructions since I now have to completely tear mine down to pieces :( I hate flying blind. Youtube couldnt help this time.
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any of them can get damaged by moisture pretty quick, and they should be broke down dried and lubed regularly .. figuring out how the first time is the hard part, id look up youtubes on benji and chinese pump disassembly, im sure theyre all pretty similar ... after you do it the first time it doesnt need to be tightened as much and it gets pretty easy .. in some cases tubes etc can be flipped if the sealing end is damaged also .. so yeah, you may need a few tools, vice, strap wrench etc to break it free the first time .. clean it up and have some ~30w silicone oil to lather everything up real good when reassembling ..
 
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I had 8 HILL pumps over the years, always had the air drier models and all of them rusted and pitted pretty fast,.....the past 4 years I used one 50 bucks China pump with no air drier and it's still as spotless as it was on day one.

Anybody can do whatever they want with their money and if they feel that if they drop 300 bucks on a HILL they will get a superior product,...just go right ahead.

Me, after 15 years or handpumping, 8 HILLs later, 2 FX and even a couple Hatsans, I take a 50 bucks China pump without even blinking.
 
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I'm new to the hobby and haven't purchased any equipment yet or a PCP. I had planned to buy a hand pump and other accessories while making a decision on an air gun.

Would we have the same concerns over moisture with the electric pumps? And concerns over moisture entering the gun?

Electric pumps are considerably more expensive, but If I can avoid problems down the road I'll save up and buy an electric pump.

Or do you have to disassemble the gun regularly and clean due to moisture buildup regardless of the pump you use? 
 
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Dawg,

First started into PCPs with a $50 Chinese handpump and a $310 Umarex Gauntlet. Even with an extra "cotton-insert" inline filter, still managed to add moisture to the gun. Next PCP was an FX Wildcat MK3, a strenuous handpump workout and fears of moisture damage, led to a $272 investment in a Yong Heng. I've six PCPs now and all are fed the most filtered, driest air I can manage. Here's my set-up, the filters are as follows; copper-colored coalescing, black "cotton-insert," gold "three-media insert," and blue "cotton-insert." I fill guns on higher shelf to make it harder for moisture to reach, however, frequent checks of cotton insert in black filter, so far, reveals only a dry and clean condition. WM 
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Thanks Dizzums. As always I learn things the hard way. To be sure I have pumped the hell out of it, string after string working out the spring and hammer tunes. I pride myself on maintaining my equipment. Now I've found I need to do it more often. I did pull the outer tube up to stop and lube that with the grease it came with... once. How many pump ups do you usually go between lubes? Tucker5373, I did look at that video, that's similar but not a Mk5 and it's not in English, I appreciate the link though. I think I'll go ahead and buy the Hill piece and look around for an after pump filter/drier just for good measure. Any suggestions? I'm finding strong opinions on pumps around here ha ha
 
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Cool set up WorriedMan! That would be me if I had big bore air hungry guns and bottles for sure! What I use the whole thing for is casual plinking, punching targets, and trigger time. I'm finding half the air gun is the air source. I got into it the Hill half way tonight, carefully... need to get the proper oil for reassembly since everything on my shelves is combustible. It's a very interesting mechanism
 
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Dawg,

Filters are pretty common for PCP compressor use. Copper-colored coalescing filter (eBay) is around $125. Not really a filter, has no media, just internal chambers that direct air down, then back up to exit, trapping heavier oil and water molecules at the bottom. Small black "cotton-insert" filter came with Yong Heng, long gold filter (eBay) has plastic three-media canister insert and burst disc, around $90. Blue "cotton-insert" filter (eBay) was bought for hand pump, now serving on Yong Heng. Head to eBay and search PCP compressor filters and check them out. Pretty sure you'll recognize them.

LeadandAirFun,

Don't know fun until you fire up one of these set-ups and fill your PCP! My shooting practice is similar, my concern was damaging my expensive PCP collection with introduced moisture. I've seen the green, slimy gunk and the corrosion it causes, don't ever want to see it again. WM
 
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Just the other day I opened up a 10 years old PCP ( ok not quite ten but 9 years old :) )

Hanpumped the gun exclusively and absolutely zero moisture or corrosion damage inside, and that has been my experience for the past decade and an half.



I believe that some manufacturers are prone to damage because of the bad materials they use ( seems like the reports of damage always involves the same guns ) regardless if they are pumped from a compressor or by hand.



I've read very good reasonings why actually a compressor will put moisture in a gun way more then a Handpump,.....if I find it I'll post it.
 
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A very good read for those that are scared of Handpumps and moisture in the gun :



" The humidity level of the ambient air has almost NOTHING to do with whether or not water vapor makes it into the guns when air is compressed. Nothing!

If you "do the math" on water vapor, compression, and condensation, you will find that it is all about the temperature of the air charge leaving the compressor - this defines the amount of water vapor that will be carried into the gun or tank after compression. If the temperature of that air charge is high (for example, around 140 F), then even a relative humidity of just 2% would pass water vapor into the tank. About the only place where the RH is low enough such that water vapor would never be an issue in compression under any circumstance would be Antarctica in the in the winter - an air conditioned room is not going to matter.

Hand pumping, done right, does not cause a problem because the air charge cools down before passing into the gun, and the water vapor condenses out to liquid before it gets to the gun. The air going into the gun is at 100% RH (for that level of compression) but won't condense out further, as the RH drops down as the pressure drops when the gun is shot.

Powered compressors are a whole other matter - run them long enough and they will be passing water vapor into the reservoirs because the air charge does get and stay hot, as they simply do not have enough "heat sink" material to cool it down (the base of a hand pump does this on them). This water vapor will condense out as it cools down in the gun or tank - it is not a lot of liquid water (probably just a drop or two per fill, as highly compressed air can't hold much vapor to begin with) but it will build up over time. As with hand pumps some can be shot out, but if there is too much getting in it will build up over time, and these pumps will pass more into the guns to begin with.

With powered pumps, an inline desiccant is highly recommended. They will work without a PMV (pressure maintaining valve) but will work better with one - this is because the build up of pressure forces condensation to occurs and that reduces the load on the desiccant. Without a PMV you'll simply have to change or recharge it more often. "
 
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