Author Topic: Cheap 4500 psi 12V compressors  (Read 640 times)

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Offline Owly055

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Cheap 4500 psi 12V compressors
« on: February 03, 2020, 11:14:19 AM »
The popularity of PCP air rifles (precharged pneumatic) that use very high pressure tanks has resulted in a crop of inexpensive compressors that will run on 12 volt or 110 volt or both ranging well below the $1000 mark.   Some at least advertise being suitable also for scuba.... around $350.  If these are truly viable for scuba tanks, it would be difficult to justify NOT having one.    A great way to consume surplus solar or wind power usefully.  Personally I feel that ANY way to consume solar and store it in a useful form..... compressed air, ice, fresh water from your watermaker, cooking, etc...... is virtual money in the bank compared to larger batteries.   I can't imagine anybody who would not consider having a full scuba tank or two onboard to be an asset.

                                                                                 H.W.

Offline s/v Faith

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Re: Cheap 4500 psi 12V compressors
« Reply #1 on: March 03, 2020, 12:05:22 PM »
Brilliant! 
Satisfaction is wanting what you already have.

Offline wolverine

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Re: Cheap 4500 psi 12V compressors
« Reply #2 on: February 05, 2021, 07:44:35 PM »
I'm big into PCP air rifles.  I have SCBA, SCUBA tanks, and a 12v compressor.  While the small compressors can fill to 4500psi, they don't have the high quality air filtration breathing air needs.  There are relatively small diving compressors, but they're around $5k.  Even if you could assemble the correct moisture filtration system, these inexpensive compressors are throw-a-ways and wouldn't last 6 months in a marine environment.

While cruising the Keys years ago, I was lent the use of a unit that pumps fresh surface air to a regulator on a 60' hose.  I found it was very adequate for underwater hull cleaning and because the air is not compressed, you can safely stay down as long as you want. or until the it runs out of gas.

Offline Owly055

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Re: Cheap 4500 psi 12V compressors
« Reply #3 on: February 16, 2021, 11:40:31 AM »
I'm big into PCP air rifles.  I have SCBA, SCUBA tanks, and a 12v compressor.  While the small compressors can fill to 4500psi, they don't have the high quality air filtration breathing air needs.  There are relatively small diving compressors, but they're around $5k.  Even if you could assemble the correct moisture filtration system, these inexpensive compressors are throw-a-ways and wouldn't last 6 months in a marine environment.

While cruising the Keys years ago, I was lent the use of a unit that pumps fresh surface air to a regulator on a 60' hose.  I found it was very adequate for underwater hull cleaning and because the air is not compressed, you can safely stay down as long as you want. or until the it runs out of gas.

The Hooka rig has been around for ages, and as you say is perfectly adequate for bottom cleaning and even more.    I know people who use them in dinghies in relatively shallow water to explore the bottom.  There is really no reason why one or more people couldn't use something like this to "grab a breath".   The most interesting parts of the sea are are arguably the shoreline and the bottom.  As a child, I often hyperventilated to allow me to stay under water for extended periods of time.  I  knew the dangers, and flirted with that fine line.  Hyperventilate too long and you will pass out.  Ultimately it got me into trouble at about age 12, when another kid who had observed me imitated me later, and drowned in the local swimming pool.  I was blamed for his death and banned from the pool for the rest of the summer, only being allowed back the next year after swearing on a stack of bibles so to speak, that I would not ever do it again........ It only stopped me from doing it at the pool.  I still use the technique in rivers, lakes and the ocean, but it requires care and judgment.  I well remember losing my glasses in quite deep water on Kauai....(yuppie strap broke) ... in a deep clear pool.  Various people tried to recover them and couldn't.  I couldn't see them from the surface, but knew where they were approximately.  I hyperventilated and dived to the bottom, and carefully explored it until I found them, staying down far longer than anybody thought was possible.   I expel breath so I can stay down.    Hyperventilation is to expel CO2 more than anything, as your CO2 level is what forces you to grab a breath.   Scuba is better....but you do what you have to do.   I've done scuba diving, but never gotten certified.

    Oil is the problem.... It's primarily what needs to be separated out, and the filters for that are as you suggest expensive.    A friend of mine had an old compressor that had been used as the first stage in an ancient scuba fill station once.   It was filled with castor oil because it is non toxic, which suggests that their filtration in those days was not great.   It's possible to get a fairly decent PCP compressor along with a scuba rated filtration system for well under $1k now, with the compressor being around $400.   "Throw away" means different things to different people.   With proper maintenance, I suspect that you would get a fair number of years out of one of those compressors.  It would be nice if someone else would pioneer using them and document their results.  I'd rather someone else made the mistakes and saved me the cost ;-)

      I own a PCP air rifle and  love it.    I can't afford the high end ones..... or rather can't justify them.    At 22 caliber, regulated and with a no bounce hammer, I can get over 30 accurate regulated shots out of a charge, and it will punch through a propane bottle easily at 30 meters.  With the 3:9 scope I robbed off one of my hunting rifles, that marauding raccoon in my garden never knew what hit him... a 22 caliber pellet at a bit under 1000 FPS  through the head is quick and humane........ and dead silent.   I'm just beginning to play with slugs a bit but the short range of pellets makes them safer.  I won't shoot a 22 cal slug where I wouldn't shoot a 22LR rifle.
     I use a high quality hand pump, and it takes about 50 strokes to charge to max once I drop below reg pressure.


Offline Norman

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Re: Cheap 4500 psi 12V compressors
« Reply #4 on: February 18, 2021, 08:23:52 PM »
That is a pretty expensive and complex alternative to a cheap 22 and CBee shorts.  730 FPS, 29 gr. gives a very quiet shot, and effective on small critters.

Another alternative is standard velocity shorts, 1100 FPS, 29 gr. and subsonic, so quiet too.

A friend has a high end spring air that is noisier than the CBee's, and less accurate than the shorts.