Air compressors - help?, an education Options

[VaccaRabite]

So I went to Home Depot today, armed with some scratch and the will to buy an air compressor and a DA air sander.

HD sells the husky line. So, I went to the tools, found a DA sander (Husky, needed 4cfm @ 90psi, and the box said it would work continously with 20+ gallon compressors).

Then I walked over to look at compressors. They had a Husky 24 gallon compressor that flowed 5.1 cfm @ 90 pis on sale ($225). Score! but then, on top of the motor, was a little chart with reccomended tools and non-reccomneded tools. All sanders and DA sanders were non-reccomneded.

I called over a HD floor guy, who called over another 2 guys, and we could not see a good reason for the prohibition. But, we decided that if the factory did not reccomend it, then it should not be used as such, and I walked over to the electric tool section and bought an electric DA sander. (IMG:style_emoticons/default/sad.gif)

I am going to need to buy a compressor by the spring. I'm clearly in the "hobbiest" catagory, and may not use the tool again for a long time aftyer I am done with my 914, but when it comes time to paint, it will probably be cheaper for me to buy one then rent one - given the slow nature that I work. I want to know why the sander was not reccomended, when the compressor could flow the air and had a big enough tank according to the tool. I have theories, but I thought somone here might be able to give better advice.

Thanks

Zach

[Borderline]

I do, however have a 30' run of pvc before the hose, angled so the water will run back into the compressor after the air cools, and that's what has prevented any water problems.

sww914: everything I've read says not to use pvc for compressed air. What pressure are you running and what size and schedule pvc are you using? I would like to use pvc to save some money but also like to be on the safe side.


I'm surprised someone has mentioned Home Depot and Trekkor hasn't chimed in. (IMG:style_emoticons/default/chairfall.gif) (IMG:style_emoticons/default/chairfall.gif) (IMG:style_emoticons/default/chairfall.gif)

[sww914]

I do, however have a 30' run of pvc before the hose, angled so the water will run back into the compressor after the air cools, and that's what has prevented any water problems.

sww914: everything I've read says not to use pvc for compressed air. What pressure are you running and what size and schedule pvc are you using? I would like to use pvc to save some money but also like to be on the safe side.


I'm surprised someone has mentioned Home Depot and Trekkor hasn't chimed in. (IMG:style_emoticons/default/chairfall.gif) (IMG:style_emoticons/default/chairfall.gif) (IMG:style_emoticons/default/chairfall.gif)

I haven't read that, but I've never researched the subject either. I have 1" so there won't be much pressure drop over 30' but I don't remember if it's sch40 or sch80, it's the thick stuff you can get at the hardware store. I've worked in a bunch of body shops and at least half had PVC, the others had iron or copper. Copper is probably the best, but it's so blinking expensive that the shop owners use the smallest that they can get away with and the guy in the stall farthest away from the compressor only gets 80#, and the other guys close to it get 125#.
I'm running 150#, and maybe I can't recommend that you do the same, but it's worked for me for 2 years. In a shop, about once a year or so, the pvc will blow out somewhere and you have to shut it down for a 1/2 hour, but it's easy to fix.
I have mine at the top of the wall, so WHEN it blows it won't shoot me right in the nuts with a pile of hardware or whatever, and now that I think of it, all of the shops that had PVC had it running way up on the wall, except for the drops down to the outlets.

[Twystd1]

As a option for PVC.

I just got done doing a whole shop in Copper.

A friend of mines Harley shop. I owed him a favor.... (IMG:style_emoticons/default/KMA.gif)

3/4 inch copper.. At 25 bucks a 10 foot stick. Plus all the 90s and couplers.

It cost a mint to do it.

The reason..?????????????

A 3/4 inch schedule 80, 90 degree PVC elbow shattered and nailed a mechanic in the face.

Bout an inch below his eye... Took 12 stitches to fix the wound.

The system has a constant 125PSI in the lines.

I have seen this time and again.....

And I have seen PROPERLY installed PVC air lines have ZERO problems. For years..!!!!

Most folks don't hang PVC properly. Most folks don't use primer on all joints.

Most folks don't inspect all of the plastic fittings before asembly.

And most of all.... folks thread in metal connectors too deep into the plastic female connector and put a stress point in the plastic... Thats a time bomb waiting to happen.

And the colder PVC gets. The propensity to shatter is excaserbated.
(love that word)

Me... I won't use PVC..... I don't like the odds of an occasional flying piece of shrapnel in a shop or garage.

Then again.... I am a nut case when it comes to doing stuff right.
(read: usually expensive)

Cheers and watch out for flying objects.

Clayton

[Twystd1]

SWW914.

I live in a mecca of chemicals. There is enough silicone in the air in the commercial area of Costa Mesa to make a painter just cry from fish eye.

The ONLY way we have been able to lower the propensity for fish eye was to either add smoothy to our paint (I hate that but it makes the paint silicone compatible)

OR: clean any oil and water out of the air system before painting anything. That made a huge differance for our final coats. less blocking... less color sanding.

I live next to the beach. Humidity changes by the hour here. salt is in the air, silicone and all kinds of crazy stuff from chemical company's and from Porterfield racing brakes corp around the corner. Makes it difficult to get a really bitchin CONSISTENT final coat.

Thats is just how it works for me....... Like you.... i am just coming from my experience...

Cheers....!!!!!!!! (IMG:style_emoticons/default/biggrin.gif)

Clayton

[morph]

i use pvc to run all my air lines.(1/2 pvc is rated at 300psi) the connectors are rated twice as high.its pretty safe ,unless you wrench down to tight on the threaded connections and crack it.and it does not explode (IMG:style_emoticons/default/biggrin.gif) it just bleeds air out the crack. just buy the pipe hangers to tack to the wall real good and your good to go. if you got allot of vibration at the tank use a flex hose from the compressor to the pvc line.i have never seen a 110 compressor keep up with a da,for very long that is.i also have air lines that are only for paint and resin spray.
james

[DBCooper]

The reason that little compressor said it wasn't rated for a DA sander is because of its duty cycle. It may be able to flow enough air to run the tool, but not continuously. Compressors and tools usually list a duty cycles as a percentage, like ten minutes running, five minutes down. The tank should hold enough air, in volume and pressure, to cover the five minutes it's down. If the compressor doesn't get a chance to cool then bad things happen, just like the engine in your car.

NEVER use regular schedule 40 Home Depot PVC water pipe for high-pressure air lines. I know that people have had luck with schedule 80 or CPVC, which is more malable and stays stronger at higher temperatures. But I've also heard about it exploding, too. PVC can lose half its strength with summer heat. and the combination of heat and pulse vibrations from the compressor will eventually cause it to fracture and then explode. In fact I understand that OSHA prohibits PVC in in commercial air line use. If you have any choice at all go with copper, but if you need to plumb it yourself and don't use it heavily or often at least use high pressure rated schedule 80 PVC or CPVC.

Also you should probably have an older compressor ASTM inspected occasionally. Most towns will have someone who's qualified to do the inspections. The reason is that condensation will eventually corrode the bottom of any air tank, and once it corrodes all the way through it will go out the roof of your garage like a rocket. That tends to happen at inopportune times, and will be something I guarantee you and your neighbors will never forget, even if no one gets hurt.

[bmcwilli]

What about PEX?

Don't shoot me...I just have been wondering if PEX is up to the task.

Thanks

[736conver]

Another option for air compressors is a gasoline powered one. I had one a few years ago worked excellent. Had a very high CFM output and was always able to keep up with my DA and cutoff wheel. Down side was the noise and having to add gas. But at the time I didnt have electrical out in my garage, so it worked great.
Now I have 100amp service and a nice 80 gallon compressor

[PRS914-6]

Regarding the PVC.....First let me say, I would use copper if you can afford it.. With that said, I used PVC. My shop is big and I have air outlets everywhere. No problems with 17 years of use at 150psi. I attribute that to several factors.

1. At each wall drop termination, I used a 2" long metal pipe fitting to an air coupling. I made metal brackets to attach them to the wall. When you pull on the lines, no pressure is put on the PVC, only on the metal to metal pieces.

2. All PVC is in the wall. No explosion worries and no sun exposure

3. The pipe and fittings were well primed and glued using commercial grade PVC cement.

If you are considering exposed PVC, and it breaks\explodes you could do some very serious harm to yourself and vehicles that are close so be careful if you do this route.

[Borderline]

(IMG:style_emoticons/default/hijacked.gif)

Vacca: Sorry, I hijacked your thread, but a lot of good info..

Thanks guys!

[VaccaRabite]

No problem. I am reading and learning.

Zach

[1bad914]

Go here and ask questions about any garage subject, www.garagejournal.com/forum/ Mine is huge, 25 cfm @175 psi, 2-stage Curtis , bigger is better! I did use a Sears 25 gal 110 for years, it would never keep up with a DA, but I painted many cars with it.

[VaccaRabite]

Okay, so I am changing my focus here.

I would like a reccomendation for a relativly inexpensive compressor that would be able to drive a paint gun. While an HVLP gun would be nice, if they require 60 gallon compressors then I can't justify it.

Sanders and other high CFM tools are out of the scope of this search. At this point I have eletric grinders and DA sanders.

Ideally, I'd like to be abel to keep it in the 26 - 30 gallon range, as that would still be more or less portable (wheeled) and I would be able to use it for other tasks outside my garage (air nailers, floor nailers, etc.)

The short term goal is to be able to lay down primer and paint in the spring, without having to hire a pro painter. I guess what I am looking for is an economical compressor/paint gun combo that is not crap, but also not designed to be used all day every day.

Zach

[morph]

not to be off subject. i stand corrected,i did a small search and i guess pvc can explode (IMG:style_emoticons/default/biggrin.gif)

STATE OF WASHINGTON
Department of
Labor & Industries

Hazard Alert
FOR IMMEDIATE RELEASE May 26, 1988


PVC pipe not to be used in compressed air systems

OLYMPIA -- The Department of Labor and Industries warned today that plastic polyvinyl chloride (PVC) pipe cannot be used in compressed air piping systems without the risk of explosion.

When PVC piping explodes, plastic shrapnel pieces are thrown in all directions.

"We're seeing more incidents of explosive failure, and we're citing more employers for using PVC air system piping," said Paul Merrill, senior safety inspector in L&I's Spokane office.

"It's probably just a matter of time before someone gets seriously injured in one of these explosions unless everyone pays more attention to the manufacturer's warnings," Merrill said.
Last year, a section of PVC pipe being used for compressed air exploded 27 feet above a warehouse floor. A fragment of the pipe flew 60 feet and embedded itself in a roll of paper. Fortunately, nobody was in the area at the time.
A PVC pipe explosion in a new plant in Selah broke an employee's nose and cut his face.

PVC piping buried 3 feet underground at a Yakima manufacturing plant exploded, opening up a crater approximately 4 feet deep by 3 feet across.

back to your question most paint guns that are not name brands (spendy) are chinese knock offs. i have four binks knock off in service for the last five years.and i will retire them after the the end of 06.with flawless service. as far as the compressors avoid the oiless ones there junk.
james

[Matt Romanowski]

For the most bang for the buck, look for something used. If you have a 914 and are used to rebuilding things, a compressor is easy. Look for the biggest you can afford. I've never heard someone complain that their compressor makes too much air....

[jsteele22]

Wow, a really great thread. I wish I had gotten this kind of advice on how to pick a wife ! (J/K)

I just wanted to expand a little on the 110/220 issue, in case it's useful to anybody. (Read at your own risk.) Any house in the US with electrical service already has 220 V service. What you get are two distinct phases (call 'em A and B ) that individually wave up (positive) and down (negative) with respect to neutral/ground (zero). The big (only) difference between A and B is the timing; A is pos while B is neg, then they cross zero at the same instant, then A is neg while B is pos. All of the 110V circuits in a house (plugs, lights, disco ball) have their hot wire hooked up to one or the other phase. In order to use a 220V appliance, you just need 2 hot wires : one for both A and B.

The only absolutely safe and legal way to get 220V is to have a certified electrician pull a permit, do the work, and have it inspected. Ouch. But if you just want to run a 220V appliance on an occasional basis, you just need a hot line from phase A and B to it (plus neutral, plus ground). If you already have a 110V outlet, you are halfway there. In principle, all you need is an extension cord (make sure it's rated for enough current) and plug it into an outlet fed by the other phase. (You can check with an A/C voltmeter. Each hot wire will read 110V with respect to neutral, but reading from one hot to the other will give 220V, or zero if they are the same phase).

This will work, but it's a little dangerous. To be safe, you need a way to make sure that if one phase (say A) draws too much current, that BOTH phases will shut off. You do this by making sure that the circuit breakers in the main panel that feed your A and B phases are next to each other. (The breakers in a panel always alternate A/B/A/B/....). Then, depending on the brand, there's usually a way to mechanically link them with a piece of wire or a pin so they can only switch on and off together.

Based on the above, a slightly more elegant (but still cheap and not entirely legal) way to do the same thing would be to buy a 220V breaker (a pair of adjacent 110V breakers permanently linked together), a box of Romex (10 gauge, 3 conductors plus ground) and an electrical box with appropriate socket, and make a custom extension cord. When you plan on using the compressor, you can hook up the wires (A,B, neutral, ground) to the main panel and you're good to go.

I'd say if you decide to do something along these lines, find someone who has some experience with home wiring, or buy a book, or both. My main goal here was to point out that the lack of "real" 220V service isn't an absolute roadblock to using a decent compressor or welder for the occasional DIY CSOB. Hope it helps.

[orange914]

1 get stand up not space consuming laydown style
2 120v not 220v its much more portable for around the house projects
3 DUEL stage brings air pressure up quicker and keeps more constant
4 DONT get oiless -way loud!!!- (IMG:style_emoticons/default/stromberg.gif)
5 add adjustable pressure regulator inline if not equipt already

[736conver]

Okay, so I am changing my focus here.

I would like a reccomendation for a relativly inexpensive compressor that would be able to drive a paint gun. While an HVLP gun would be nice, if they require 60 gallon compressors then I can't justify it.

Sanders and other high CFM tools are out of the scope of this search. At this point I have eletric grinders and DA sanders.

Ideally, I'd like to be abel to keep it in the 26 - 30 gallon range, as that would still be more or less portable (wheeled) and I would be able to use it for other tasks outside my garage (air nailers, floor nailers, etc.)

The short term goal is to be able to lay down primer and paint in the spring, without having to hire a pro painter. I guess what I am looking for is an economical compressor/paint gun combo that is not crap, but also not designed to be used all day every day.

Zach

Whats you budget?

[VaccaRabite]

words words words.....
Zach

Whats you budget?

Ideally ~400 max for a compressor, with a paint gun that works well as cheaply as possible.

Zach