Hill handpump dessicant replacement

[mtsheron70]

For you Hill pumpers.............when or how do you know when to replace the dessicant beads in the pump?  Thanks!

[RatRacer]

When the beads change color if saturated, blue or pink, and don't change back. You can extend their use life when they get saturated by baking in oven on a sheet pan at around 200° until they're white again.

[mtsheron70]

When the beads change color if saturated, blue or pink, and don't change back. You can extend their use life when they get saturated by baking in oven on a sheet pan at around 200° until they're white again.

Awesome!

[MustangMike]

Open it up and pluck one bead out and drop it in a glass of water to see if it expands and what color it changes to

[bnowlin]

If you need to buy some, I noticed that straightshooters has it.

[Devin]

I wouldn't worry about it too much. There was some testing done on those beads some years ago and showed after a thorough baking, they were nearly fully saturated after only a couple hours.

If you bake them prior to every use, I could see some benefit in using them, but other than that they are pretty useless. The extra filters on the dry-pack certainly do not hurt though.

[Ribbonstone]

Here's the testing I did a few years back:
http://www.network54.com/Forum/79537/message/1255313355/Dry+Pac++testing

Whatever that stuff is, its not dissicant.  Seems to absorb more moisture than dissicant, but is chenically changed in the process, so baking it doesn't make it release the moisture like dissicant granules will.

To stay on top of it, in my climate and with my pump use, would need to change it monthly.

[Devin]

Here's the testing I did a few years back:
http://www.network54.com/Forum/79537/message/1255313355/Dry+Pac++testing

Whatever that stuff is, its not dissicant.  Seems to absorb more moisture than dissicant, but is chenically changed in the process, so baking it doesn't make it release the moisture like dissicant granules will.

To stay on top of it, in my climate and with my pump use, would need to change it monthly.

Ha! That's the very thread I remember reading. I didn't know that was you, lol.

I guess I mis-represented the dry pack pebbles a little. I was once worried about replacing them until your experimentation. I came to the conclusion that it wasn't practicle enough to worry about anymore with how regularly it would need to be changed at $15 a bag + shipping.

[MustangMike]

maybe a few of you hill pump owners needs to track down exactly what hill is using and all of you go in on a bulk buy and split it up evenly.. buy enough to where you only need to do a group buy once a year or twice a year

[Devin]

maybe a few of you hill pump owners needs to track down exactly what hill is using and all of you go in on a bulk buy and split it up evenly.. buy enough to where you only need to do a group buy once a year or twice a year

Well, I'm trying to figure out which viewpoint to take on the current situation.

One case, is that they use a material that somewhat "locks" moisture away, so we don't have a simple method (baking) to "renew" the pebbles for reuse. This keeps some customers coming back to buy more.

Another possibility is that they use this material because there is some benefit to having a material that doesn't release moisture as easily, keeping our PCP's cleaner.

Either way you have to keep up with refreshing/renewing the material if you want to get the most out of the dry pack, whether it be Hill's material, or a general dessicant.

It seems the logical choice is to use something that can atleast be baked back to a fresh state weekly, or even bi-weekly if needed, vs spending $20 every month just to keep a fresh supply of Hill's stuff in the dry-pack. This is of course if an alternative dessicant isn't prone to releasing moisture in certain conditions while in use.

Does anyone know at what temperature general dessicant releases its absorbed moisture?

[yoshi800]

I just bought some dessicant from cabelas called 40 gram silica gel - It says to reactivate: place unit in vented 300 degree oven for 3 hours (or until window (the silica gel) turns blue again.  I keep it in my gun safe to keep water vapor from attacking my gun.

[MustangMike]

to be honest guys unless ur hand pumping in very humid weather its really not needed. ive had my disco for awhile now and have used the benji hand pump. ive never found any moisture or signs of moisture in my disco and believe me ive had it apart more times then most people take their disco's apart in 2 years


so dont get to paranoid and go over board, id also say the stuff would come in handy more if you hand pump outside. ive never pumped up outside, i always stay inside to fill my disco

[mtsheron70]

I just bought some dessicant from cabelas called 40 gram silica gel - It says to reactivate: place unit in vented 300 degree oven for 3 hours (or until window (the silica gel) turns blue again.  I keep it in my gun safe to keep water vapor from attacking my gun.

I have similar products I use in my reloading cabinet to keep the dies and all from surface rust.  You do the same as yoshi stated, they are in a metal canister and bake them in the oven when they turn pink at a certain temp. for a few hours until blue again.

[mtsheron70]

Seems I have started a real think pot here.  I just wondered if there was a indicator or expertise on this as far as a general use time.  I would say like MM stated I pump my gun up mainly inside in a air conditioned environment.  Unless I see some evidence of moisture collecting alot I will change out the material every 3-4 months to be safe.  It would be nice to know what they use and buy in bulk like one post suggested.  I may check on that.

[markasaurus]

I have a used hill pump and have no intention of replacing the desiccant...I'm with Mustangmike, its not practical.  Next hill pump i buy would be the one from championschoice, they sell the hill without the desiccant holder for $220...i paid $225 for my used one...having already torn it apart 3 times for inspection and lube, i can tell you YES water does form in the pump.  Is the desiccant going to be effective for long, probably not.  Its indeed impractical to keep buying and replacing the desiccant at about $25 everytime.  For me a better, probably only course is tear the pump apart every so often and just clean out the water.  And maybe the gun once a year to inspect and clan the air chamber too.  My money doesn't grow on a tree in my garden, not willing to change desiccant all the time!  Keep the pump lubed how it is supposed to be and i don't think you will get corrosion inside.

[Tad]

I don't have experience with the hill pump drier, but lots of experience with desiccants in general.  When exposed to air, desiccants pick up water.  Unless you completely seal off a desiccant with an air air tight seal, they will quickly become saturated in a matter of hours.  So, unless the drier is completely sealed off after every use, it is useless.  Almost all desiccants can be regenerated by heating, but the number of cycles is limited.  The regeneration temperature depends on the desiccant.  Silica gel can be regenerated at about 212-250F, but most require a much higher temperature (some as high as 450F).  If someone gives a description of what the desiccant looks like, I may be able to tell you what it is.

If it's not silica gel, then heating to 200F will not regenerate most desiccants. 

I would imagine it becomes saturated (and thus of no use) after pumping a few times, even if sealed in between use.

Perhaps a good selling tool, but I would guess it is absolutely useless if used in the way I've heard people using it: changing it a couple of times a year.

[mtsheron70]

Nothing will ever be 100% effective in a hand pump nor a SCUBA/SCBA tank as far as moisture is concerned.  As far as the Hill repacks they are $8 and not $25 so I would check where you buy those puppies.  I think the upstroke with the introduction of ambient and sometimes moisture laden air is the purpose of the dessicant compartment on a Hill.  Yes, the moisture still will build on the internal from pumping and the friction created heat of high pressure and the outside surrounding air which creates this.  Just like a cold winter with heat on the inside and cold outside and the condensation that accumulates on a window glass pane < no different.

Hill pumps are still the best on the market and form and speed is the true deterrent to excessive < notice excessive not complete loss of moisture.  You pump like a jackrabbit on a date you will build excess condensation internally, you do it controlled and deliberate and take a break you build less. 

That is why a pump is usually a third the price of a tank.  But tanks can do the same.  Trick there is the same; slow fills compared to a quick burst of air to fill the gun.

[Tad]

Desiccants can reduce water levels to the ppm level.  If properly used, they would completely eliminate condensation 100%.

Compressed air has less capacity than ambient pressure to retain water.  No matter how fast or slow you pump, if you are drawing in humid ambient air, you will have the same amount of condensation somewhere.

Hot air has a higher capacity to retain water.  If you pump quickly, the heat generated has less time to dissipate, and so the air will have a higher moisture content when entering the gun.  This may lead to condensation in the gun as the air cools.

Pumping slower allows the pump to be cooler, so moisture is more likely to condense in the pump, rather than the gun.

From a tank, it makes no difference.  The amount of moisture in the tank is a constant.  Fill fast or slow, it does not matter in terms of condensation.  Rapid fills can generate heat however, which is bad for seals.

Condensation can never occur when filling from a tank anyway, unless the gun is used at a lower temperature than the temperature of the bottle when the gun was filled.  All the condensation has already occurred, either in the compressor, or the bottle.

Manny has hand pumped for years in a very humid environment.  He has torn his guns down, and seen no moisture related problems.  Even if some moisture condenses in the gun when filling, it is most likely gone after a few shots.  The pressure in the gun goes down, the water capacity of the air goes up, and the condensation evaporates.