SpudFiles

Hey guys i was looking around today trying to find portable compressor. I found a 12v rechargeable pistol grip one that will do up to 120 psi. Which will be fine for my little gun. But when i want to step up to higher psi what is the best "portable" method?

Here is the small one i found. If anyone knows of a better one please let me know.

http://cgi.ebay.com/Brookstone-AirPro-C ... 0549102813

There are none (AFAIK). The amount of power needed to compress a reasonable amount of air to a reasonably high pressure in a reasonable amount of time is too much power for a handheld portable device. If you want portable at high pressures, your best bet is a human-powered pump of some sort.

maybe a car air con compressor?

There is really no way to make a worth while compressor that is compact and fits in your hand. the more portable compressor that is worth anything is going to be like a 2 gallon gas powered compressor, and im not even sure if they make gas compressors that small.

Home Depot just got in some 135 PSI 1 gallon compressors that are 0.75 SCFM at 90 PSI.

It is an off brand of this one. Other than the brand and color, it is exactly the same.

http://www.homedepot.com/webapp/wcs/sto ... reNum=4018
They will run off a 1KW inverter like I use with my car. I'm thinking of picking one up as they are only $99. The advantage to an AC powered compressor is most can run continuous instead of 10 minutes on and 30 minutes cool down due to a 30% or less duty cycle.

This would allow higher pressure on my Marshmallow cannon.

There is a thread on portable field power.

http://www.spudfiles.com/forums/how-to- ... 18124.html

I currently use this compressor on this inverter.

This is this compressor. Sadly only 100 PSI
http://www.harborfreight.com/1-3-hp-3-g ... 97080.html

hi wrote:There is really no way to make a worth while compressor that is compact and fits in your hand. the more portable compressor that is worth anything is going to be like a 2 gallon gas powered compressor, and im not even sure if they make gas compressors that small.

You can get a small glowplug engine for very little, suitably geared down it would have more than enough power to make one of those silly little 12V compressors reach higher pressures. The disadvantage is that it's noisy and inconvenient to start. There are certainly high powered electrical options out there though, look at high performance brushless motors for RC models.

Look here;

http://www.spudfiles.com/forums/loki-t6676.html

You know, this is kinda unrelated, but I wonder... If you made an adaptor with standard spark plug threads, could you use your idling car to fuel large hybrid chambers?
You know... basically it converts one cylinder to a fuel/air compressor and the rest are used to power it. (Obviously not going to work with an old diesel )

Fnord wrote:If you made an adaptor with standard spark plug threads, could you use your idling car to fuel large hybrid chambers?

I'll have what he's drinking

You'd have to adjust the carburettor to make up for the chamber volume... and would the fuel stay atomised in the hybrid chamber, or would it condense?

Fnord wrote:Look here;

http://www.spudfiles.com/forums/loki-t6676.html

You know, this is kinda unrelated, but I wonder... If you made an adaptor with standard spark plug threads, could you use your idling car to fuel large hybrid chambers?
You know... basically it converts one cylinder to a fuel/air compressor and the rest are used to power it. (Obviously not going to work with an old diesel )

would that make the car a hybrid?

Hmmm... at first I thought the exhaust stroke of the cylinder would be a problem, but if there were a check valve between your cylinder and chamber, the exhaust stroke would actually draw in combustion products from the exhaust for a moment (since the piston will pull a vacuum on the cylinder on the power stroke).

Shouldn't require adjustment of the carburetor at all, I think, since it meters out gas based on flow into the cylinder(s). You would have to purge your hybrid's chamber with an inert gas or else the air in the chamber will throw off the mix...

Limits you to 10x, though...

EDIT: if you have an engine with a waste spark system (two plugs per cylinder, like my Ranger's), you could dedicate a cylinder to an air pump by welding the intake and exhaust ports over, removing the valve stems/push rods, and installing check valves in opposite orientations on each spark plug hole... your modern PCM might go batshit on a modern vehicle, though... also need a valve on the outtake which you can open to allow free intake and flow out when starting...

You don't need to purge with inert. Leaving the air (80% nitrogen, which is inert) would do the same thing. You'd get no less power than if you purged with inert.

I don't think you'd need to add a bleed valve to start the engine. Cars must be able to crank against the compression stroke to stand a chance at actually starting.

Oh, Harbor Freight is selling a 6.5hp horisontal shaft engine for $75 now.

ramses wrote:You don't need to purge with inert. Leaving the air (80% nitrogen, which is inert) would do the same thing. You'd get no less power than if you purged with inert.

You're adding air to an otherwise (nearly) perfect fuel/air mix, which would make it slightly lean.

Not to drag this thread back on topic, but.........

Have you looked into Helix or Viar compressors? They run on 12 volts and my Helix runs well over 200 PSI. Heck, I have seen 310 psi with two Helix compressors on 24 volts.


Matt

I'm impressed. The helix is one of the very few 12 volt with 100% duty cycle.

Don't let its good looks fool you - with a 100% Duty Cycle and a bevy of high-test specs, the HEXAC6 brings the brawn you need to ride low.

At 40 amps power draw, it will flatten a UPS 12volt 7.5 Amp Hour battery in about 8 minutes. The little pistol compressor in the OP will deliver much less air. Don't run this without a charging system running that can keep up.

The problem with small battery operated compressors is they are very limited in capacity. They may be good for topping off a soft tire in an emergency or filling a mid size air cannon once or twice, then they run out of power.

Well, it is 100% duty cycle if you are not pushing it super hard. I can tell you that my twin compressor setup gets too hot to touch charging my two gallon tank up to 230 psi. But, once I get off a shot, check the carnage, and go back for another, it has cooled down.

I may put fans on the heads to make sure everything is ideal.

Matt