Compressor

[D911]

I've been lookin for a compressor for a little while now.
I want to use it for things like sanding, grinding, and eventually painting my car :)

I saw this in the flyer
http://img201.imageshack.us/img201/7130/compressorwallmartqb1.jpg

wondering what you guys think of it, if its any good or if I should keep lookin?

[Supa Dexta]

Yes that will work for that type of work. We used to use one similar for painting cars..

[Sharpie]

Shouldn't be to bad for sanding/grinding, but if you want to paint with it you will probally have to paint a section at a time.

[SilverBoost]

Yeah I have that compressor and you'd prob want one bigger for painting because it constantly comes on with any type of straight use. You'd certainly want a good water separator on it of course as well.... but you'd want that on any compressor that you'd use for painting. Over all, it get's the job done though for the guys on a budget.

Best thing about it is it's smal and you can poke it prety much anywhere andmove it when you need to. Larger compressores almost require you keep them stationary and use a permanent type wall mount hose system. Since I don't own the house I live in right now, I'm more interested in a more mobile system that setting up a large compressor, so this works great for that as well.

[D911]

Alright, so the general concensus here is that it's not too bad..not great, but good for a guy on a budget (ie. Me)

I havent done enough research on the painting portion of my plans, because Im not going to attempt that for a while longer, but care to explain the part on the water seperator?

[barbarian]

A water separator is a little can that goes on the inlet stream to the compressor (or the outlet stream as well). Basically the incoming air is diverted towards the bottom, and moisture in the stream tends to separate out. Suction air is drawn from the top of the can and (ideally) has no free water droplets). Excess water accumulates in the can and there is a valve to release it.

In my ideal world, there'd be a water separator on the compressor inlet, on the outlet (into the tank), and just before whatever tool you're using on the end of the hose.

You can see what these look like at any place that sells compressors.

A shop that has a large compressor set up might have a dessicator or an after cooler with another separator.

Here is a good explanation: http://www.truetex.com/aircompressors.htm

Wet Air: As much as you might want to believe that your carefully-chosen compressor is providing a useful supply of compressed air power, the fact is that without an expensive drying unit, your compressed air is of very limited application. This is because the "air" being sucked into your compressor does not consist of just compressible gases like nitrogen and oxygen, but lots of water vapor. In all but the very driest climates, the compression from atmospheric pressure (14.7 psia at sea level) to the total tank pressure (typically, 100 psig = 115 psia, or so) compresses the atmospheric water vapor to the condensation point inside the compressed air tank and delivery system. This is why you have liquid water collecting in the tank, which must be periodically drained. But the water does not stop at the tank. While you can strip any liquid water out of the air line with an inexpensive coalescing filter, the water vapor remains everywhere in the flow of compressed air at close to the condensation point (100 percent "relative" humidity), and will condense into liquid with the slightest cooling downline from the initial heated temperature. This is why you can have liquid water sputtering from your air lines into your tools, tires, paint spray, etc., even after a so-called filter/dryer; hot, steamy air fills the air line even after the filter, and if allowed time to cool, the humidity condenses into liquid water. While this water-contaminated air spoils the lubrication in your air-powered tools, robs power, throws your tires off balance, etc., it positively ruins the operation of tasks like painting and sandblasting that cannot contaminate the work with specks of liquid water or water vapor. You do not just have compressed air, you literally have compressed steam as well. (Tell your friends your shop is steam-powered!)

Dry Air: The only solution to wet air is a refrigerated air dryer. This is a unit that costs more than many small compressors. It is essentially a small air conditioner that chills the air stream running through a coiled tube, thereby condensing almost all the water vapor to liquid, which liquid is then separated and drained out of the unit. Such a unit is all that is needed for most dry air applications, yielding a relative humidity of about 10 percent in the output air, literally drier than a desert. For demanding applications requiring even less humidity, dessicant filters with a complex system to regenerate themselves with heat are used, typically after a refrigerated dryer, yielding a truly near-zero humidity. The grim thermodynamic reality is that there is no easy or cheap way on a small scale to purify air from contaminating water vapor. Water is a problematic contaminant in compressed air, and wet air is greatly inferior to dried air. Think of it as another thing the Sears salesman didn't tell you about the compressor's performance, namely, that without further expensive treatment, it produces water-contaminated output.

[SilverBoost]

Originally posted by D911
Alright, so the general concensus here is that it's not too bad..not great, but good for a guy on a budget (ie. Me)

I havent done enough research on the painting portion of my plans, because Im not going to attempt that for a while longer, but care to explain the part on the water seperator?

The water seperator is basically a filter you put in-line on the air-line so that water doesn't come out of the end of the line. In the case of painting, it's be in your paint gun, and then of course spray out on your paint casugin water marks on your paint job and to put it bluntly, fucking it up.

Compressing air creates condensation in the tank, (simple explanation) so unless you filter it out, it'll come out the line.

There are cheap ones like for $20 you just put in-line, but pro-painters have devices that are a lot more expensive.

[ninspeed]

That is way to small to run an air sander/Air Board, grinder, or even a paint gun. Even a 60 gal is small if your doing a large job.

[dj_honda]

Originally posted by ninspeed
That is way to small to run an air sander/Air Board, grinder, or even a paint gun. Even a 60 gal is small if your doing a large job.

:werd:

10cfm @ 90 psi, is what i was told is a min. for proper bodywork/painting.

[Supa Dexta]

See "you were told".. I've actually painted cars with something similar to this compressor, so I know it will work for what he needs, yes it will come on, but in the time your going from panel to panel it can keep up. I've never painted anything bigger than say a camry or 4 door acura, but for that it is enough. This is just your backyard paintjobs, but they come out pretty decent for what it is, a non professional job that still looks good and holds up... It is on the smaller side, but how much work is he doing, his car?

[SilverBoost]

Yeah, for "proper bodywork and painting" that thing is not the answer, but it can be done. Just don't expect a foose job. :)

[Tik-Tok]

Originally posted by D911
I've been lookin for a compressor for a little while now.
I want to use it for things like sanding, grinding, and eventually painting my car :)

wondering what you guys think of it, if its any good or if I should keep lookin?

Before you buy a compressor, look at what tools you plan on getting for it, sander, grinder, paint gun, etc. and find out what the minimum SCFM@PSI they require to operate will be, then you will know how powerful of a compressor to buy.

To give you an idea, most "Touch-up" paint guns require around 3 cfm's @ 40psi, and a real paint gun will require more than 6 cfm's @ 40psi.

You'll need to look at the numbers on that particular compressor pump to find out if it's what you need.

[D911]

Lots of mixed answers here.

So I'll go find out the CFM when i get some time tommorow. That'll probably help a bit to decide.

[Kor]

I'm looking for a compressor too!

Princess Auto supposedly has one that will do the trick 10cfm @ 90psi which I was ALSO told is the minimum for any kind of auto painting by a friend of mine who has done a lot of painting in the past. Its < $650 and is WAY bigger.

Harbour Freight tools in the US has capable compressors for around $350US but they are over 200lbs and so I doubt you can ship up here.

Portable one like this will be maybe 5cfm tops, my friend told me that this would cut out in the middle of painting a panel and it might seriously become a pain in the @ss if I want what I am painting to come out looking decent.

I would love to find a used compressor that is similar to the princess auto one for < $500 but I can't find one yet.

[benyl]

http://forums.beyond.ca/showthread.php?s=&threadid=136078&highlight=air+compressor

[barbarian]

Princess Auto also sells a HVLP Turbine spray system for ~$130. Not sure what kind of a job it does, probably better than a rattle can.

[dj_honda]

also worth checking out house of tools and costco as benyl pointed out.