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I've decided to give spraying a try. I started off by looking at the recommendations for the finish I am using for a spray gun and they say a .030" - .034" tip at 30 - 45 psi. So I looked around and read some threads on this forum and decided on Walmec ES-RV Detail Spray Gun. One of the main things I liked about this gun is the extremely low CFM requirements - only 1 - 2.1 CFM. So I ordered it from Jeff at Wood Essence. I also ordered the 3M PPS set up as that looks very slick to me. Having done that, I bought an 8 gallon, 200 psi compressor that does 4.7 CFM @ 40 psi. One of the uses they gave for this compressor was spray painting small items and they showed a picture on the box of someone spraying a lawn chair with what looks to be a standard size spray gun. So I thought I was all good.

I got a message from Jeff and he said he doesn't have the adapter required to fit the 3M PPS to the gun, but he may be able to find one. He also asked if I might be interested in the Walcom EGO for which he has an adapter. It's more money but you also get more so I would consider it. The problem is that the EGO consumes 3.9 - 6.0 CFM, at a working pressure of 29 - 36 psi. So I'm not sure the compressor I got will be up to this gun.

Can anyone advise me on if they think my compressor will work with the Walmcom EGO spray gun? It seems to me that a guitar is not a very big surface to cover. I'd be surprised if I couldn't get a whole guitar covered without the compressor even turning on.

Thanks,
Pat

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There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

One thing to consider is how large a project you will be spraying. If you are finishing guitars and small furniture projects, you'll spray about 60 seconds to 2 minutes at a time, so basically the size of the tank is more important that the capacity of the compressor. For larger projects the compressor/tank might be too small, but for guitars I think your compressor/tank combo is large enough.

I have a SATA Minijet IV gun, which requires 4 cfm (very good gun BTW). My compressor is large (12.5 cfm @ 100 psi) with a 25 gallon tank set at 120 psi. I usually spray 2-3 coats before the compressor kicks in to boost up the pressure in the tank. Your tank is smaller (8 gallon vs. 25 gallon), so your compressor will probably kick in at the end of each coat, but I doubt the line pressure or volume delivery would drop below the minimum before the coat is finished. It sounds like your compressor has a high tank pressure rating (200 psi). Using the higher tank pressure will let you get through a larger spray job without the compressor kicking in, but then the compressor will require longer to recharge the tank.

I have a Walcom EGO - it's a nice gun and I also have the 3M PPT system so clean up is super easy. I run mine at 29 psi. I use a small Ingersoll Rand jobsite compressor and have no problems.

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Steve Smith
"Music is what feelings sound like"

8 gallons is not a lot of air, once that drops below the lower pressure limit and the compressor kicks on you will be able to use air faster than you are making it. On small objects like guitars this may not be a big problem. Something else to consider though is that compressors that run higher duty cycles also tend to put more water and depending on design, oil into the air. Both of which are the enemies of good finish

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

I'm not an expert on spray guns, and I've used fairly inexpensive guns for the most part. I'll just offer a comment on your compressor. I used an 8 gallon compressor for years to spray my guitars. For a while I had a tiny shop and it was all I had room for. It worked ok, but the compressor would kick on pretty quick and run continually while I sprayed. A couple years ago I gained access to a new shop with a large industrial compressor. I noticed improved quality in my spraying.

So you can get away with an 8, but in the long run you'll probably be happy with something bigger. Even a 20 Gallon would be a big improvement. Nice thing about the 8 is that it is very portable.

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Josh House

Canadian Luthier Supply
http://www.canadianluthiersupply.com
https://www.facebook.com/canadianluthiersupply?ref=hl
House Guitars - Custom Built Acoustic Instruments.
http://www.houseguitars.com

Thanks everyone for your comments. Josh, what kind of gun were you using with your 8 gallon compressor, i.e. what were its CFM requirements? There does seem to be a decent selection of detail guns that have a CFM usage in the 3 - 4 CFM range and, since my compressor does 4.7, I'm hoping it might be enough. Also, Jeff at Wood Essence seems fairly confident he'll be able to get a PPS adapter for the gun I actually had ordered and it only needs 2.1 CFM.

I have been thinking about the 15 gallon 200 psi DeWalt compressor but to me, that's a whole other level of space usage in my shop. The 8 gallon compressor fits nicely under a bench and I do like the portability.

Pat

_________________
There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

I was a bit optimistic, but it should work for small projects even if your gun draws the full 6 cfm. A few basic calculations - with an 8 gallon tank starting at 150 psi, and ending at 60 psi you have 181 "standard" litres of air in the tank. "Standard" (also called "normal") means the volume when measured at atmospheric temperature and pressure.

Your gun's air consumption is measured in standard cubic feet per minute (scfm). To complicate things your compressor is rated to deliver 4.7 scfm if the tank pressure is 40 psi - but - your tank pressure will be higher than 40 psi and the compressor will deliver less standard volume as the tank pressure rises. At 100 psi tank pressure the compressor might be delivering only 1 scfm...and working darn hard to do it - so I would not rely on the compressor keeping up to the gun, you need the tank to provide surge capacity or else a you will need a more powerful compressor.

If your gun draws 6 scfm (170 litres/minute), that means you will draw down the tank pressure to 60 psi with 1 minute of continuous spraying. Your compressor will kick in and extend this time somewhat, but it is not very long. Below 60 psi tank pressure I would worry about running out of air on that final critical pass and buggering everything up. Hopefully the gun you choose operates at the lower end of the 3.9-6 cfm range you mentioned.

If your gun draws 4 scfm (113 litres/min) then you will draw down the tank in 1.6 minutes.

If your gun draws 4 scfm (113 litres/min) and you start with a tank at 200 psi, then you will draw down the tank in 2.5 minutes. I don't like operating my tank at very high pressures because the compressor runs forever trying to get that last 10 psi of pressure into the tank.

I also did the above calculations for my compressor & gun (25 gallon tank, 120 psi initial pressure, 80 psi final pressure (this is when the compressor will kick-in)), and I can spray for 2.2 minutes before the compressor would kick in. This is close to what I observe when spraying small projects. Two minutes of continuous spraying is quite a bit.

Anyway, if I was buying a gun in your circumstance I'd go for a gun that consumes less air or I would upgrade the compressor.

Pat, I highly doubt you're going to have a problem with that setup. Guitars don't take long to spray. I've sprayed with many combinations and never have I had a compressor rated high enough for the guns I have. Not even close. But as mentioned, the size of the project is the key. I've sprayed pickup trucks with small compressors and that's where you KNOW the difference. The compressor runs forever, gets real hot, starts condensing water in the line, and spurting it all over the finish, not to mention you have to wait and wait for the comp to build up enough air to continue. Guitars, I can spray a coat, neck and body, and be back in the lazy boy in under a minute.

Thanks very much for doing and posting those calculations Steven. Between your calculations and Glen's additional comment, I'm almost tempted to try the higher capacity gun. Sounds like I'd have about 1.5 minutes of spraying at 6 CFM if I started the tank at 200 psi.

Pat

_________________
There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

I understand how you feel, you don't want to invest and waste your money. I have never had enough compressor and sometimes I think about getting tough with the problem, running 230 v to my garage and buying a 2-stage Ingersoll Rand. Then, I could run a dynabrade DA.
Kathy Matsushita uses a 4 gallon CH pancake compressor with a full size HVLP gun. That is really not supposed to work, but apparently it does for her.
http://theamateurluthier.com/amateurlut ... slist.html

I used to use a Wagner hvlp gun with my 8gal compressor. 46psi at the compressor, 16-20 psi at the gun. I did my first two kitchens with this set-up, so I don't imagine that you will have any trouble spraying a guitar.

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

Don't forget to add in the filters, water trap etc. I also added a dryer on mine (only to the spray gun) - a bit pricey but I wanted to be sure the air was dry.

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Steve Smith
"Music is what feelings sound like"