Miniature gas powered compressor?

[StaggeringGoat]

I'm wondering if something like this even exists, and if not I want to make one. I have one of those little 2 cycle/800 watt generators from Harbor Freight and I love it. Not a ton of power, but it's very portable and very cheap. Not for every day use but it works when I need it.

I want the same thing in an air compressor. Portable - one man can easily put it in a trunk. Cheap. Doesn't need to last forever, or have all the bells and whistles, just needs to make air. Doesn't even need an air tank or a pressure switch - just run balls out until you shut it off.

Did they ever make such a thing? I have searched and searched but cannot find anything. If not, I'm building my own. I'm thinking of buying another 800w generator and taking off the 2 cycle engine. I would need a little air pump that I could direct drive up to about 3600 RPM. Maybe buy a cheap oilless compressor and steal the pump from that? Any other ideas?

 

[Burtonrider10022]

I'm gunna guess your best bet is DIY, as it seems you are already leaning to. What are you trying to/hoping to run with this thing? A pump with enough CFM to keep you happy isn't going to be very small.... In all reality, a gasoline motor is nothing more than a giant air pump, and horsepower is a side effect. air comes in, gets burnt, goes out.

Obviously, this is totally feasible, most easily done IMO would be, again, with a generator motor because of the varying throttle/governor. So as the pump compressed at a higher PSI (if on a tank) the motor would turn faster. This may not apply, IDK really.

If it were me... I'd do 2 small hot-dog tanks as a base and then a belt drive pulley set up. get a belt drive pump, small gas motor, a couple old, broken harbor freight hot-dog compressors for the tanks and go to town.

 

[Burtonrider10022]

Actually, I take it all back.

Buy this: http://www.amazon.com/dp/B000FIY08U/?tag=atomicindus08-20

and this: http://www.amazon.com/dp/B000BM8RT8/?tag=atomicindus08-20

and rig the wires up, then plug into your existing generator and enjoy 2.7 CFM @ 120PSI


That's a pretty good brand, too. Reviews around the web are good from most of the off-road community.

 

[RPH]

I have a hookah setup that was used for diving back in the day. Bs powered and enough air to keep 3 divers happy. About $400 twenty five years ago. Still works though.

 

[Dustball]

DIY route-

Gas engine of your choice with a horizontal shaft.
York A/C compressor (search Google for York onboard air for types to get and mods to make)
Pressure switch for the York electric clutch

The York compressor will have the output you want and is oiled so it won't burn itself up.

 

[Outlawmws]

How much air pressure do you need/want? One of those old time constant pressure compressors with a gas motor might be all you need? (see Jack's thread on "tabletop" compressors)

If you need more, then something with an electric clutch as Dustball mentioned is probably a better route.

 

[Jawn]

Actually, I take it all back.

Buy this: http://www.amazon.com/dp/B000FIY08U/?tag=atomicindus08-20

and this: http://www.amazon.com/dp/B000BM8RT8/?tag=atomicindus08-20

and rig the wires up, then plug into your existing generator and enjoy 2.7 CFM @ 120PSI


That's a pretty good brand, too. Reviews around the web are good from most of the off-road community.

That won't work, it looks like the compressor draws something around 30 amps, according to a reviewer. That AC/DC power supply is only rated for 5.8 amps. You'd fry the power brick in short order, if it would work at all.

 

[Burtonrider10022]

Meh, technicality. Find a different power supply. Use a smaller compressor. get a small has engine and put a car alternator on it and use that to run the 12v compressor.

Actually... That could work really well

 

[firebox40dash5]

Meh, technicality. Find a different power supply. Use a smaller compressor. get a small has engine and put a car alternator on it and use that to run the 12v compressor.

Actually... That could work really well

If you're overcomplicating stuff, take it all the way, man!

The York idea is cool, but IIRC you have to put oil into the intake air, and then preferably run a water seperator on the output to pull it back out, as it's designed as an A/C compressor and needs oil in the "air" (formerly freon, with oil in it) for a long life.

 

[StaggeringGoat]

That won't work, it looks like the compressor draws something around 30 amps, according to a reviewer. That AC/DC power supply is only rated for 5.8 amps. You'd fry the power brick in short order, if it would work at all.

Actually I already have two of those compressors, but they are impossible to power for more than a couple minutes. Yes, they use 30 amps each...that's more than the alternator in my truck puts out. And I don't know where the 2.7 CFM number came from, it's more like 1. If I was going to go that route I'd just buy a small 120v compressor, but anything that will run from an 800 watt generator will be pathetic.

Some of you seem to be missing the point. It MUST be small and light. That means no pulleys. No Briggs and Stratton engine. No compressor pump with a steel block and an oil reservoir. Think outside the box.

Harbor Freight did sell what I want a few years ago, but they only sold it for a few weeks and then it disappeared. Never seen anything like it again. It was basically one of their cheap little oilless pancake compressors with a 2 cycle engine.

 

[Dustball]

If you're overcomplicating stuff, take it all the way, man!

The York idea is cool, but IIRC you have to put oil into the intake air, and then preferably run a water seperator on the output to pull it back out, as it's designed as an A/C compressor and needs oil in the "air" (formerly freon, with oil in it) for a long life.

Not if you do the York oil passage mod found all over the net in onboard air write-ups.

 

[greasemonkey44]

you could hook your 2 stroke motor to an old ac compressor to run some cfm out of it
iirc a friend of mine is doing that on a chevy truck with a really old york compressor

 

[03protege]

Actually I already have two of those compressors, but they are impossible to power for more than a couple minutes. Yes, they use 30 amps each...that's more than the alternator in my truck puts out. And I don't know where the 2.7 CFM number came from, it's more like 1. If I was going to go that route I'd just buy a small 120v compressor, but anything that will run from an 800 watt generator will be pathetic.

Some of you seem to be missing the point. It MUST be small and light. That means no pulleys. No Briggs and Stratton engine. No compressor pump with a steel block and an oil reservoir. Think outside the box.

Harbor Freight did sell what I want a few years ago, but they only sold it for a few weeks and then it disappeared. Never seen anything like it again. It was basically one of their cheap little oilless pancake compressors with a 2 cycle engine.

How old is your truck? I think the simplest answer here may be upgrading your alternator. I didn't know they even came as low as 30 amps.

 

[03protege]

you could hook your 2 stroke motor to an old ac compressor to run some cfm out of it
iirc a friend of mine is doing that on a chevy truck with a really old york compressor

That is what I was thinking too, I have a 49cc 2 stroke that is light as hell and revs pretty high (don't remember the actual RPM)

 

[Burtonrider10022]

You're being awfully damn picky here. Sorry for all the legitimate solutions I've come up with for you. I don't see how the generator you ALREADY said is the size you're looking for would become "too big and heavy" if you had an air pump the size of a football with it.

But since you're so adamant on wasting the money on a second motor, just buy one of THESE and remove the electric motor from it.

Also, to your "IDK where you got 2.7 CFM from" I was quoting the manufacturer. Sorry that I didn't check your personal reference notes before consulting with the people who made it.

 

[StaggeringGoat]

You're being awfully damn picky here. Sorry for all the legitimate solutions I've come up with for you.

LOL! Sorry, I don't see any of those "legitimate solutions" from you. I'm simply sticking to the original parameters I gave in the first post.

I don't see how the generator you ALREADY said is the size you're looking for would become "too big and heavy" if you had an air pump the size of a football with it.

I didn't say that. I said anything that runs off of an 800 watt generator is going to be pathetic - the kind of compressor you use to air up a basketball. It would have to be less than 800 running watts to account for the startup surge. Turning mechanical motion into electricity and then back into mechanical motion with a motor is extremely inefficient and bulky.

But since you're so adamant on wasting the money on a second motor, just buy one of THESE and remove the electric motor from it.

Not even close to feasable. None of those compressors are even close to a few horsepower.

 

[StaggeringGoat]

How old is your truck? I think the simplest answer here may be upgrading your alternator. I didn't know they even came as low as 30 amps.

It's got a 37A alternator. It's 40 years old. Yes, a bigger alternator is something I want to get, but I still want a compressor that doesn't need a seperate power source - no battery, no generator, no truck.

 

[Burtonrider10022]

I asked on the first page and I haven't seen a reply yet, if I missed it I apologize, but what exactly do you want from this compressor? What max PSI, what CFM, what duty cycle are you hoping to see from it and what are you intending to run/power with this compressor. If you had just answered that question you'd have gotten more specific replies.

 

[StaggeringGoat]

I asked on the first page and I haven't seen a reply yet, if I missed it I apologize, but what exactly do you want from this compressor? What max PSI, what CFM, what duty cycle are you hoping to see from it and what are you intending to run/power with this compressor. If you had just answered that question you'd have gotten more specific replies.

Nothing specific - it would just be good to have around when something comes up, much like the generator. I'd like to get the most CFM I can in a small package, I think around 5 CFM should be the minimum. A standard 120 PSI would be nice. I'm thinking instead of any kind of pressure switch or throttle control, it would simply run on high all the time and have a blow off valve for when it isn't being used to capacity. Now that I think about it any kind of oilless pump probably wouldn't hold up to that kind of use.

I'm starting to think about using a twin cylinder engine, with one cylinder converted to a compressor, and the other one driving it. (Like they used to do with V8s before they had diesel powered screws) Still probably a bit larger than I really want...

Years ago I got stuck out in the woods with 3 flat tires and then my electric compressor blew up. I had to walk like 30 miles out. Now I like compressed air.

 

[Burtonrider10022]

Yeah, that's above my knowledge level. Most home owner grade compressors don't put that much CFM out so your original plan of using a direct drive compressor is kinda shot. IDK how you could get around a belt drive set-up for that kind of demand in that size...

 

[StaggeringGoat]

I believe most piston compressors put out around 4 CFM per "real" horsepower, but that's definately going to go down if I try to drive something at 3600 RPM.

Does anybody know how fast the cheap import direct drive compressors usually spin? I'm thinking either 1800 or 3600 RPM.

 

[TapperMan]

These might be a little larger than what you want, but it might provide some inspiration...

http://www.govliquidation.com/auction/view?auctionId=5820318&convertTo=USD

http://www.govliquidation.com/auction/view?auctionId=5823980&convertTo=USD