Air tools are safe to use with explosive vapors present. Electric tools have brushes that have sparks.

 

You can also turn the air pressure up or down as needed. Hard to do with electric tools.

 

Electric has to spin-up for full torque - not counting any gearing --

Pneumatic has full torque at start up ---

 

This is false. DC motor have full torque when in a locked rotor condition but develop some extra momentum impact at speed. DC motors typically lose some torque as speed increases. AC induction motors (usually used in larger stationary power tools) may have a complicated torque curve, but starting torque is higher than rated torque (and typically more than low speed torque but less than high speed torque but more than full speed torque). Universal motors (used in many AC powered hand held power tools) have highest torque in locked rotor condition.

And, yes, I have sheared off bolts using electric tools, starting from a locked rotor condition.

Compressed air is a very inefficient way to transmit power. 80-85% of the energy is thrown away as heat in the compressor before it even reaches the tool.

 

If you are a professional, then you need the air tools for your shop.
That means spending the money for a good system.
I am leary of the oil free air compressors they sell home owners.
So I bought a air compressor that uses oil, hoping it would last
longer. My Garage only has 110 but my compressor uses 110 or
220vts? I used it with 110 and it blows fuses.

My point is: if your not going to use power tools every week
for several hours I don't think its worth the money and hassle.
Its far easier and more convenient to for your average home
owner to have a good cordless tool system, along with several
corded tools.

 

If you are a professional, then you need the air tools for your shop.
That means spending the money for a good system.
I am leary of the oil free air compressors they sell home owners.
So I bought a air compressor that uses oil, hoping it would last
longer. My Garage only has 110 but my compressor uses 110 or
220vts? I used it with 110 and it blows fuses.

You have a problem with your amps, not your volts, if you are blowing fuses.

 

I have spent the past 30 years using compressors and air tools and spray equipment.
A large piston style compressor with a large storage tank will run a large shop,
providing that every tool station has a oil/moisture trap at each station, and you are
not at altitude. It is really a tradeoff between Cubic feet per minute at higher P.S.I.
compared to amperage draw on an electrical tool. I have an ancient 8" Black and Decker Angle grinder, and nothing short of a 200 gallon tank with a 20hp compressor would even come close to give me 6 to 10 CFM at !00 lbs continously that I would need for a comparable air grinder. It depends on the tool, and the amount of time you are going to be using it, and most critically it's CFM requirement. Think of PSI like voltage, and CFM like amperage.

 

Most electric motors are only capable of about 1 horsepower with 110 volts.

An air compressor can be 5 horsepower with a bigger electrical outlet like 220 volts @ high amps and also they store energy in the air tank. This makes them very powerful tools without a bulky motor built in.

But for most people air is really only useful for impact guns, air hammers/chisels, and other tools that require high power. I used to use them on medium duty trucks because electric won't do it.

I have an electric impact gun from Craftsman that works great on cars and light trucks though. I think electric tools are more reliable than air tools too.

 

Since you are talking about a generator or a engine driven air compressor I'd suggest going with a generator and using electric hand tools.

Engine driven air compressors are less efficient than generators, and air tools are much less efficient compared to electric hand tools.

Depending on your climate, dealing with water in your compressed air can be very problematic. You'll need Water Separators and air oilers and they aren't cheap and need constant attention. Then there is air regulation, not all hand tools are made to operate at the same line pressure.

A medium generator will handle most hand operated power tools and it will be some what portable compared to a LARGE engine/compressor needed to operate hand tools. And you'll have electric power for lights.

Plus, a electric generator will need less maintenance.

 

I would also like to mention I owned a few of the RIGID gas powered air compressors from Home Depot and they are very tough. We beat the hell out of them every single day and the Honda engines keep going.

 

If your air source goes down, you are without power tools until it is fixed. With electric tools, you can run them off line power, generators, or a inverter hooked to your car battery. Throw in a couple of cordless tools and you'll always have a power tool available. I've got a few air tools, sometimes they are darn handy, but most of the time I rely on electric tools.

 

A lot depends on what type of work you're planning to do. Construction trades use some air, mostly electric, and cordless tools rule! Ryobi makes an 18v charger that plugs into a cigarette lighter/power port, I plan on picking one of those up in the near future...

I haven't seen a table saw, band saw, drill press, mill or lathe that runs on compressed air, they might exist but why reinvent the wheel...on ebay I have seen these engine driven generator/welder/air compressor combination units that look really cool and useful, very expensive, but very useful!

http://www.ebay.com/itm/Campbell-Ha...ir-Compressor-Combo-GR3000-NEW-/281041019197?pt=Power_Tools&hash=item416f59a13d

 

the expensive part is the compressor. though you can buy a good 2 stage pump.

http://www.harborfreight.com/145-psi-5-hp-twin-cylinder-air-compressor-pump-67698.html

get one of those 50 gallon well pump tanks and you have a compressor that will be able to run your airtools with no issues.

trust me those air drills use allot of air

 

any power tool has a manual tool that will do the job,with a little more elbow grease.

 

Post-SHTF, it seems to me that an air compressor being spun by a windmill or water wheel or similar, that's perpetually filling a large (500 gallon or so) air tank, would be quite advantageous... You'd always have the air there when you need it, no fuel, and it keeps te load of large electric tools away from your off-grid electric system.

 

I uhhh don't think that would work.

 

Like everything in life there are tradeoffs. Air compressor means 1 big expensive electric motor. Electric tools mean a lot of relatively expensive little motors. Air tools can be cheaper but you also have to buy hoses, filters, oil, connectors, etc.

I bought a little oil-less air compressor from the big box store over 10 years ago and as soon as I got it I wondered how I ever got along without it. I still have it and use it often. It handles most things I need to do with air.

I recently bought a really nice (for a home shop) air compressor.

Buy good tools and keep them cleaned and oiled.

 

I think that some have missed the part where Randyt (OP) is talking about an ENGINE driven compressor or generator.

...."I got to wondering about the feasibility of using a engine driven air compressor to run tools rather than a engine driven generator."....

There will be no electric motor on the compressor.

 

all i have to add is MAKE SURE YOU HAVE A MOISTURE TRAP. A company I worked for bought a large tank compressor ( about 80 gallon or so). The techs who installed it ( our own service techs) did not put in any traps on the several air lines running from it, just an auto perge on the bottom of the tank. After a few minutes, you were spitting more water through the tool than air and making a hell of a mess.............

 

thanks for the comments. I was thinking in terms of off grid or post SHTF.

 

Off grid or post shtf it would be nice to have both electricity and air...some tools work more efficiently when powered by one rather than the other. You can't use electricity alone to blow out a clogged fuel line or inflate a tire, compressed air won't give you light to work by. And if you are generating electricity, I believe that generating enough to support the ability to weld is essential, but I realize that this is not everone's priority.

I would love to have an engine driven multipurpose unit like the CH Power Pack or one of the other commercial variants out there. Since they are mostly gasoline powered they can be converted to propane as well and perhaps alchohol too if you lived in an area where alchohol production could be a possibility...I keep watching ebay for one, if i don't find a used one at a reasonable price I am considering building my own sometime after this project is completed:

http://www.survivalistboards.com/showthread.php?t=275369&highlight=12v+power+source

I'm thinking perhaps a 6cyl car engine with 1 or 2 cylinders dedicated for air compression, I still have a lot of research to do on that one...

Have you considered something like this:

I looked on Craigslist for a long time before I found this unit, paid $800 and added the trailer and tool box. I have about $1300 in it today. It's an 8kw generator along with a welder...

 

that's a nice welder. I had a portable that my grandad built but it didn't have any power outlets. It was run with a hand cranked wisconsin. I may get it back from my brother and rework it to have 120 volts. And also add electric start. I currently have a ac/dc lincoln buzz box and a miller 250 wire feed.

 

And a compressor will never run a welder!

 

110v stuff like a drill, saw, etc can run off an inverter. But alot of variable speed stuff doesn't like low end inverters. So a cheap on/off drill might work but that expensive variable give fits. You can of course charge up cordless stuff of a generator or inverter. Only way that would work long term SHTF is solar for the most part. Generators need gas.

Air tools post SHTF will be mostly useless. You can run an impact gun off one of those small compressors to get a stubborn bolt loose, then hand tools after that. I have 110v decent sized compressor that will run air tools for the little bit I use them. But short of a decent sized generator won't be much use post SHTF, again a generator that would require fuel. Maybe only use it when you really need it.

Post SHTF for most things your just going to go old school, hand tools. I can charge up cordless stuff off my solar array. And did buy a better inverter that will run variable speed tools. But I also have plenty of hand tools, and held onto my grandfathers hand drills, finding reasonable priced bits isn't easy.

 

A couple of points most Amish have to have special permission to have Electric in their shops.
Also if you have electric you can make Air and light, and heat, and, and; With air you have air, no lights, no heat, no well you get the idea.
Or get an engine with a standard transmission and you can run it all off the old wide belts, with extra pulleys, belts and throw out clutches!! Just need safety guards in place.

 

thanks for the comments. In the DIY there is a thread about my lineshaft that is run by a wisconsin engine.

 

My experience in home construction is that a mix of air and electric is best. Air tools are great for nailers and impact tools. Electric is better for most everything else. Air can also be a pain in the you know what in the winter. I would recommend getting a generator and a small oil lubed compressor for the best of both worlds.
Rmfcasey

 

If you arent sure, get a few, they. Try out some harbor freight ones (they are cheap, but if well oiled they are good). Or check out the pawn show. They usually have LOTS of tools at good prices!

 

I have some repulsive-induction motors on some of my equipment, they're AC. Those motors have to come up to speed, I was told that they are a great motor for starting undr a load.