air compressor for spraying woodworking projects

[john davey]

Hi all, I am looking to get a new compressor and have read that large tanks are needed to spray. Most of these sights seem to be talking about painting cars though. So I am wondering if I could use the McGraw 20 gallon compressor currently on sale at Harbor Freight to spray small woodworking projects like boxes and cabinet doors. Maybe up to the size of a Coffeys table.... Or is the 60 gallon recommendation I am seeing just correct and I am stuck? Here is a link to the compressor I am looking at...https://www.harborfreight.com/20-gal...sor-64857.html

Thanks, John...

[Jim Becker]

It's all about the gun...each gun requires a certain amount of SCFM at the expected input pressure to do the job. That's on the pump side of thing. But just as important is how fast your application is going to cycle the available air. The larger the tank, the longer you'll have air in the expected pressure range between times the pump is running..making for smoother performance and lower noise level, not to mention less wear on the pump. With many of today's guns that are LVLP or the efficient end of the HPLV scale, you can get away with the 20 gallon setup and most of those will also be compatible with a 20 amp 120v circuit.

[Kevin Jenness]

You need to consider the demand in cubic feet per minute of whatever tools you plan to use when choosing a compressor. Tank size is secondary. A large tank will allow you to work with hungrier tools for a short time but at some point you have to take a break and let the pump catch up. The unit you are looking at will run a low output gun intermittently but it is not built for the ages. Someone serious about finishing will probably have a 5 hp compressor that puts out about 15 cfm. Compressed air is expensive.

[Tom M King]

Bigger is better. I have a number of compressors, and have done some spraying with most of them. My largest is a 10hp two-stage on a 120 gallon tank. It kicks on at 145 psi, and off at 175. I forget the cfm, but the refrigerated dryer on it can handle 54 cfm at 175. That big one is the best for any spraying, which for small jobs, like a piece of furniture, the compressor never kicks on, and even on larger jobs, like re-gelcoating a boat, the whole job is the same coming out of the gun. It seems like it wouldn't matter with a low pressure gun, but it does. Everything about that big one is better though, like the regulator is built to handle more than that compressor can produce, so light duty work is no tax on it, like on the smaller, cheaper compressors.

[Travis Conner]

I have a 60 gallon 5hp quincy and I can hold a blow gun open non stop and the compressor will still reach 175psi. It takes a while for it to get to the 140psi cut in pressure. Like probably 3 minutes of me holding it open.

[Tom Randol]

I spent 20+ years owning a tire shop. You want a large low speed compressor. An Ingersoll Rand type 30 was the best 1 we ever bought. We bought several low dollar high speed compressors. They wore out soon + they were very loud. We put them behind a wall and they were still very loud.

[Carroll Courtney]

Which compressor I think is one of the hardest decision a person can make, lot harder than what table saw to buy. Just work within the limits of your compressor and the gun. Whatever material you are spraying may have to be thin down so that your spray equipment can handle. While at HF look at their spray guns and see what scfm is required and if they will be at or below the compressor scfm rating. I think that most here agree that when it comes to air compressors bigger is better which gives more scfms for any kind of project that comes along.
I would suggest one of Graco hand held sprayers but heck nothing is cheap anymore

[Dave Sabo]

I’d suggest an entirely different avenue - HVLP.

The entry level setups from HF or Earlex will get you in the game for $300 or less, and you won’t have to worry about taking oil and moisture out of the air like you will with the compressor.

[Curt Harms]

I’d suggest an entirely different avenue - HVLP.

The entry level setups from HF or Earlex will get you in the game for $300 or less, and you won’t have to worry about taking oil and moisture out of the air like you will with the compressor.

That's certainly something to consider. I have an Earlex 5000 and it's done everything I've asked of it. Would I use it to spray a show car? No, but I don't think most wood finishes are that demanding. An upside to the HVLP turbine units is that they are portable, compressors large enough to run a conversion gun really aren't. I also have a Porter-Cable PSH1 gun (no longer available) that I've used with a C-H compressor rated at 8.6@40 psi, 6.8@40 psi. That's the old rating system, there's a new standard that is more conservative. I've sprayed cabinets with it and got along OK. I found that I'd spray for maybe 30 seconds then have to stop for a few minutes to reposition the work or whatever. The oilless air pump had enough time to cool off between bouts of spraying.

Something to be aware of with turbine units is that they're always producing air. Some of the more expensive units have a function that diverts air from the gun when not in use. My Earlex and presumably other lower end units always have quite a bit of air coming out of the gun. If I'm not careful where I point the guns I can stir up quite a bit of dust. Dust and wet finishes don't go well together. Compressor powered conversion guns don't have that problem. Something that did surprise me about the Earlex is that for all the air coming out of the gun, the amount of overspray is remarkably little. I don't know how they manage it but they do.

[Tom M King]

Another thing to keep in mind about turbine HVLP systems is that they heat up the air. The more turbines you have, the thicker the coating you can spray with them, and also the better it atomizes anything, but also the more each vane heats the air. Some finishes just don't play well with them.

The absolute worst compressor I have is some unit from Home Depot with a 30 gallon tank. I needed to shoot thousands of framing nails in an attic, and didn't want to bother to move either of the large compressors for that job. I thought one of the smaller ones wouldn't run that gun, but there wasn't much less waiting with the 30 gallon tank, since the pump doesn't produce much air anyway. I forget the model of it, but it's a single stage pump on that red 30 gallon vertical tank. I'd recommend staying away from that one.

[Jim Becker]

I’d suggest an entirely different avenue - HVLP.

HLLV guns are used on both turbine systems (what I believe you're referring to) and compressor systems. I don't disagree with your recommendation, however, if one doesn't have a larger compressor to work with for spraying finishes. A turbine system can be a good option. In the end, it's the actual gun that matters, however.

[john davey]

Thanks for all the replies. A little more info from what I have read here. I am looking at a compressor instead of a turbine because I need a compressor anyway. I use finish and brad nailers as well as the blower and tire filling. I do not run sanders or automotive tools. I get 1 or 2 projects done a month and at the size of a coffee table or smaller. The compressor I am looking at does 5 scfm at 40 PSI and Harbor Freight does have guns that fit those specs. So what I am hearing is in theory this will work but bigger would be better. I really do not have space for a larger one or the 220 it might need so I will be getting this as I need it for the guns and blower anyway. IF it doesn't run the cheap HF gun I'll look into turbines and all I would be out is the cost of the cheap gun... Thanks...