Air compressor - Assorted questions

[atferrari]

Planning to buy a small air compressor but not clear what exactly; it could be even one of those used to inflate tires.

I want to clean PCs / equipment gently but effectively and I want it to have a small tank (reservoir?). It will be used for an aerograph and small air-driven machines.

My questions:
How do you call in English the valve regulating the pressure at the output?

I want it adjustable so how to tell what range it should cover?

Those 12V units, are they worth the expense?

What else to look for besides a filter / water trap?

Oil, is it a no-no for what I want it?

Found what locally is called "dentist compressor", fitted with a tank and small in size.

Always took for granted compressed air. Now I know that I know nothing about.

Please, few short sentences preferred than googling and reading long articles. Little time available here. Believe me.

The local tradition in the shipping business say that by December everything slows down. Not true. Full ahead as ever. Always. For years.

Why people insist in repeating legends?

 

[gabeNC]

I have one of these and use it for many different jobs.

Amazon.com: Porter-Cable CPF23400S 3 HP, 4-Gallon Side Stack Compressor: Home Improvement

I've framed houses with it, with the right attachments blow dust off circuit boards, impact wrench, grinder, sander etc. Lately i've been using it to spray poly on homemade speakers and it struggles to keep up, just be careful with the duty cycle.

Not sure what your budget is.

 

[Rbeckett]

A small compressor designed for air brush painters will be quite sufficient for cleaning a PCB, but will not inflate a tire of any kind. A small compressor with that capability will usually develop 135 PSI and use a regulator at the outlet to control the use of air. Air compressors are rated in CFM at PSI thus a compressor for my plasma table must produce 9 SCFM at 90 PSI to operate the machine. Thats actually a fairly large compressor. but for small cleaning and blowing jobs the small pancake type from the tool retailers would probably do both activities with minimal investment. I would stay away from the 12 volt plug in the cigar lighter types, due to short life span, high heat source, and incapable of storing any air on board when it is running. Hope this helps you more than confuses you getting started

 

[EternityForest]

As a big time pnuematics hobbyist(special effects) i would advise you to STAY AWAY FROM 12v plugin compressors.
they might be good for some things(maybe) but i have never enjoyed using one. as for oil, all i know is that painters prefer oil free compressors. also, if you plan to clean things, you for sure want a tank for bursts of air as opposed to the trickle that most comps give without a tank. be advised that all compressors are for the most part LOUD. get a big tank, run it till it fills up, turn it off, then clean if you don't want the noise. if you do this you gotta turn it off first or it will come on as soon as the tank pressure drops and startle the crap out of me at least
a bigger tank means less cylcing>longer life.

the thing that regulates pressure is calld (drum roll) an air pressure regulator and should never be confused with a flow regulator. for the most consistant job i would suggest a pressure reg first, then a flow reg, then a blowgun.
set the pressure reg to 10(gentle) to 90 (HARD) psi. most blowguns say to stay under 90psi. thens adjust the flow regulator to the flow you want. a flow regulator is really just an adjustable valve.

All of this is probably absolutely overkill for what you are doing. but if you want to be able to contron the flow it is definatly worth the 35$ or so for the regs.



also, NEVER point the blowgun at ANY body opening even from a foot away.
feel free to ask me any air related questions
-Danny

 

[BrownOut]

How do you call in English the valve regulating the pressure at the output?

Pressure regulator

I want it adjustable so how to tell what range it should cover?

Typical ranges for a small compressor is 0 - 125PSI

Those 12V units, are they worth the expense?

Not really

What else to look for besides a filter / water trap?

coiled hoses to extend the hose that comes with the compressor, blower attachments, inflator attachments, etc

Oil, is it a no-no for what I want it?

Small compressors are mostly oil-less. You can get an "inline" oiler if you need lubrication for your application.

 

[DirtyLude]

If you are using it to blow on electronics, you'll want a dryer.

 

[atferrari]

Dryer like a hot air gun running to a minimum?

 

[#12]

I burned up a 12 volt compressor in about 5 minutes. Pure crap. Wouldn't even fill a flat tire, and that's what it was sold for!

Oilless compressors use ball bearings and a teflon coated cylinder to avoid any oil. Amazingly, they work well.

I built a tiny blower from an old refrigerator compressor and a 5 gallon tank from Western Auto, but I also wired in a pressure controlled shut off switch. Very important because refrigerant compressors will go past 450 psi if you don't pay attention. If you don't know how, don't do it that way! ps, I used it for 5 years and never found any oil in the oil seperator. Must be the extra oil cooling loop that is peculiar to refrigerator compressors that have 4 tube connections.

 

[HiTech]

Planning to buy a small air compressor but not clear what exactly; it could be even one of those used to inflate tires.

I want to clean PCs / equipment gently but effectively and I want it to have a small tank (reservoir?). It will be used for an aerograph and small air-driven machines.

My questions:
How do you call in English the valve regulating the pressure at the output? It's called a regulator!

I want it adjustable so how to tell what range it should cover? The regulator will be designed to handle the specifications of the compressure's pump/reservoir tank. It will allow you to adjust from 0psi to whatever the max. output is.

Those 12V units, are they worth the expense? Automotive portable compressors for filling tires and beach balls are worthless for your application. You would do far better by blowing your breath on dusty PC boards- seriously. You need a air tank to store the accumulated air to build up pressure. The only reason your breath has pressure is because your lungs hold a certain amount of air and it compresses as you take in a deep breath. Exhaling it has it exiting out with some pressure. Same goes for a true air compressor & holding tank.

What else to look for besides a filter / water trap? Filter/water separators are mainly for protecting air tools from moist air rusting internal parts and for painting. Paint sprayers need to assure moisture and oil do not mix with the paint. For blowing off dusty items, don't bother with that extra cost. The amount of moistyre in the compressed air isn't any different than the relative humidity of the room you are in when working!

Oil, is it a no-no for what I want it? Huh? I don't understand the ? Good compressors require oil inn their crankcase cause it's nothing more than an engine without fuel exploding in it. Instead it's taking in air, compressing it, then exhaling it. Oil is also used in air tools to lube internal parts. There are specific types of oil used for the cylinder crankcase and for air tools. There are oiless type compressors that operate dry. They do not last long and fail early on by principle. Many even have rubber or vinyl piston rings that wear out fast. A decent compressor is just like a small engine, has a crankshaft, camshaft, a crankcase needing oil to lube things, a cylinder and piston with plenty of sealing rings, valves, filtered air intake, etc. ... it's just missing the spark plug!

Found what locally is called "dentist compressor", fitted with a tank and small in size.

Always took for granted compressed air. Now I know that I know nothing about.

Please, few short sentences preferred than googling and reading long articles. Little time available here. Believe me.

The local tradition in the shipping business say that by December everything slows down. Not true. Full ahead as ever. Always. For years.

Why people insist in repeating legends?

All you need is a small "pancake" compressor like those made by DeWalt, Porter Cable, Campbell Hausfield, etc. Even Harbor Freight Tools has them for cheap. The pancakes type compressors have a small 2-3 gallon tank with the compressor mounted on top of it. They run fast, build air pressure fast and provide more than enough air to clean dust off of items. They will even run small air tools and come with a regulator and shutoff valve. There are many types of air nozzles (air guns) that have extended noses that can reach into tight areas for blowing out dust. Most dust jobs can be performed with 30-50psi. Anymore than that and you can actually damage things like peeling off stickers, blowing off a small PCB connector, etc. The small cans of compressed air sold at some hardware/office supply stores works well but they are pricey and don't last long for continued uses. Hardware and major department stores sell the small pancake style units. You can also go online to http://www.northerntool.com/shop/tools/category_air-compressorshttp://www.northerntools.com or at http://www.harborfreight.com/air-tools/oil-compressors.html**broken link removed**. You can eventually buy small air tools someday and run them off of it. Like a die grinder, air saw, ratchet wrench, paint spray gun, small nailer/stapler. I wouldb't think about using impact guns, cut off wheels and the like that require much more cfm and pressure to properly do their job.
Seriously though, if you want it to last and expect to use it heavily and rely on it, get a unit that has a crankcase and requires lubricating oil in it. Regardless of the improvements with the oiless types, they still do not outlast their oiled countertypes.

Here a snappy little unit that looks quite complete and easy to transpoprt:
Discount Tools: Air Compressor 1/3HP 2.5Gal Pancake w/2Storage Bin Hose & Tip, Air Compressors, APC4009