oil free compressors - Woodworking Talk

arcscarpa · 05-20-2009, 04:52 AM

Question about oil free air compressors. I'm looking at buying a DeVilbiss oil free air compressor to use with an HVLP gun. I have read some of the posts on here about tool CFM requirements, HP and tank size. It is a 30gal tank, 125 PSI and 4hp. I'll have to look at the available CFM at 'x' psi. Mainly I am curious about opinions on oil free compressors. I don't anticipate doing any heavy spraying. I am mainly building small tables as a hobby and am looking to get into spraying finishes. Any input would be greatly appreciated.

Thanks

Just Bill · 05-20-2009, 08:33 AM

Oilless are fine for hobby work and even some production work. But will not last as long as a quality oil type unit. Make sure it is capable of maintaing the air flow/pressure your tools require.

rrbrown · 05-20-2009, 12:26 PM

Don't take this the wrong way but I think you clicked the wrong forum link. You put this under hand tools. You probably would have got allot more response in the correct thread. Nevermind I see you posted it in the right place also.

As for your question; I found that aircooled is quite a bit louder and don't last a long as the oil cooled. If those specs you gave are right it should be good enough for HVLP with no problem but Check the cfm @ psi rating to be sure.

bigredc · 06-16-2009, 09:04 AM

I have an oil-less Craftsman comp. I've had it maybe 10 years. I do a lot of bead blasting and some sand blasting, so it runs a lot. I thought for sure it would have worn out by now. It's still running strong. I will say I still hate it. It is so loud it rattles my nerves. While I'm bead blasting maybe for 1/2" hour or more at a time, listening to it run the whole time is very anoying. Functionaly I have no complaint.
Chris

GeorgeC · 06-16-2009, 10:14 AM

There is another thread on this subject.

The vast majority of respondents said they did not like the noise level.

G

GeorgeC · 07-28-2009, 06:59 AM

This is some new type of SPAM by 357ni1026747172 ???

There is another just like this on another thread.

George

rrich · 07-28-2009, 03:46 PM

First...

Are you going to spray, use air tools or just an occasional nail gun?

If you are going to spray... HVLP or regular gun?

The reason for the questions is that each use has different air requirements.

I would not attempt to spray HVLP with a compressor. The system really requires a turbine to do a good job. Yes, there are conversion spray guns out there that allow one to use a compressor in a HVLP application. These conversion guns are designed to sell conversion guns and not necessarily provide a quality spraying system. (Let the flames begin.) The name, HVLP, implies everything that a compressor is not. A compressor is not high volume, a compressor is not low pressure while as turbine system meets all of these requirements.

For air tools, you'll need a compressor system that can meet the requirements of the air tool in both pressure (PSI) and volume. (CFM or SCFM.) For our purposes CFM and SCFM are the same. The SCFM specification came into wide spread use because some lawyers were able to succeed at a class action lawsuit.

I have the DeVilbiss oil free air compressor, pancake style, that has served me well for about 10 years. I use the compressor for my nail guns, automotive tires, bicycle tires and soccer balls. It is under pressure at all times w/o a problem.

And, George, no I don't think that it is SPAM at all.

firehawkmph · 07-28-2009, 08:03 PM

First of all,
My .02 on oil less compressors, use em for a boat anchor. Way too noisy unless you have a soundproof room to put one in. Even a lot of the traditional compressors make too much noise. Whatever you buy, ask to plug it in and fire it up first, if possible. Get something that meets your air requirements and is quiet.
Rich,
I agree with your take on the turbos for HVLP guns, but I do have a unit I bought for painting trim in new houses, staining fences, etc. It has a pretty healthy compressor with twin tanks on it, a 2 1/2 gallon pot, and a 50' dual hose setup going to a spray handle. It works extremely well. But it isn't the average hvlp gun you buy in the store for 69.00. This unit is contained on a nice cart and retails for over 2000.00. Not your hobby shop gun.

Mike Hawkins

rrich · 07-28-2009, 11:31 PM

Quote:

Originally Posted by firehawkmph

First of all,
I agree with your take on the turbos for HVLP guns, but I do have a unit I bought for painting trim in new houses, staining fences, etc. It has a pretty healthy compressor with twin tanks on it, a 2 1/2 gallon pot, and a 50' dual hose setup going to a spray handle. It works extremely well. But it isn't the average hvlp gun you buy in the store for 69.00. This unit is contained on a nice cart and retails for over 2000.00. Not your hobby shop gun.

Mike Hawkins

Mike,
Exactly! My HVLP system only cost about $700. And OMG what a difference between it and a conventional spray gun!

But, really TWO Grand??? WOW! It must do a really nice job spraying!

firehawkmph · 07-29-2009, 10:19 PM

Rich,
It works very well. I sprayed all the woodwork in my mother's house when I built it for her. If you have a helper just to drag the hose and move the unit around, you can shoot all the woodwork, (casing, base, doors) in a couple of hours. Her house is a 3 br ranch, 1800 sq. feet. Makes things a lot easier. It sprays varnish very well too.
Mike Hawkins

bigredc · 07-30-2009, 09:45 AM

What do you guys think about this type gun. It's called HVLP, but it's nothing like the systems you guys are talking about.
It says to feed it with 40 psi then the regulator on the gun knocks it down to 20 psi.
Chris

rrich · 07-30-2009, 04:01 PM

Chris,

I know nothing about the gun that you showed in your post.

What I do know is that the numbers that you are quoting are only half the story. The REALLY, REALLY important numbers are the SCFM (or CFM) requirements of the gun and how many SCFM at 40 PSI will your compressor provide.

Think of it like this...

The PSI number is like voltage and the SCFM is like amperage. If you have a router, a planer and a couple of shop vacs running simultaneously on the same 15 amp circuit you're going to pop the circuit breaker. If the spray gun requires more SCFM than the compressor can produce, you'll run out of air pressure and your compressor will run continuously.

bigredc · 07-30-2009, 07:34 PM

I should have add that I have plenty of cfm.
I could set it 100 psi and open all the way and maintain that all day. I wouldn't want to, but I could.
I have a blasting cabinet that I supply with 150 psi. If I'm blasting a long time and use up all my reserves I can still hold at about 100 to 110 psi.
I get a fan and point it at the compressor to help keep it cooler. I usually don't go more than 20 minuets or so, then I do something else for a bit to let it catch up and cool off a little.