What spray guy do you use?

[Quickstep192]

I'm just starting out spraying; I'm using a Devilbiss Plus Gravity Feed HVLP conversion gun. It's a good gun, but basically an automotive gun. It seems to have a wide pattern which is hard to control for me. Frankly, I do better with a rattle can. I'm wondering if I should get a smaller gun. What do you folks use?

[charles Tauber]

In my days of shooting high pressure, low volume with a compressor, I used an automotive Devilbiss gun. They are - or were - pretty commonly used for instruments. For their HPLV guns, there are a variety of nozzle types and orifice/needle sizes that can be used to give different spray size, wetness, atomization, etc. Probably there are also for their HVLP guns.

It may be that you need only change the nozzle and/or needle to get better results. You could contact Devilbiss, or do a bit of research on what they recommend for the finish (and articles) you are spraying. Typically, you want about a 2" to 3" wide fan as a spray pattern, perhaps, widening to 4" for tops and backs. You should be able to adjust the gun to easily obtain that. Practice by spraying water on scraps of wood or paper to get the gun's spray pattern adjusted close to what you want, tweaking it, if necessary, for the actual finish material to be sprayed.

There is nothing easy about achieving a top-quality sprayed finish.

[bnjp]

I'm interested in this too. I have heard of a lot of guys using touch-up guns but wonder if they are all-purpose enough to be the only gun I use. I finish guitars and small pieces of furniture. I only spray nitro.

[mirwa]

Devilbiss are nice guns. All mine are of the brand Star. Just a cheaper version of the devilbiss. When I learnt to spray paint 20 plus yrs ago, I started by painting cars, old man was a professional painter and taught me.

The thing with guitars is we are after mirror finishes, just means a little bit more work

Automotive guns are what we all use, what is the tip size of your devilbiss,it will be written on the air cap. 1.4 is a good all round general purpose gun.

Steve

[Howard Klepper]

Originally Posted by Quickstep192

I'm just starting out spraying; I'm using a Devilbiss Plus Gravity Feed HVLP conversion gun. It's a good gun, but basically an automotive gun. It seems to have a wide pattern which is hard to control for me. Frankly, I do better with a rattle can. I'm wondering if I should get a smaller gun. What do you folks use?

Couple things: the pattern is adjustable; do you know which knob does that? It's usually the one off to the side, or on the top center. It controls the airflow from the side holes in the nozzle. The lower knob in the center is for fluid flow.

You need to find the pressure that works for your material. You didn't say what you are spraying. More pressure gives you a more finely atomized spray; less pressure a coarser spray.

The Devilbiss Plus is not an HVLP gun and not a "conversion" gun. It's a general purpose gravity feed that is meant to run at higher pressures than an HVLP (they recommend 25-40 psi, depending on what you are spraying). If you have the instructions that came with it, read them. If not, they are on the manufacturer's site. Go here and download the "Service Bulletin." http://www.autorefinishdevilbiss.com...117-literature

All the guns people use on guitars are "automotive" guns. This just means a general purpose gun. Your gun should do a good job for spraying guitars.

You need to experiment also with thinning your material (nitro lacquer?). And with the distance you spray from. So you have several variables and the only way to get good at it is to practice and experiment.

I personally have for many years been using a Binks 2001 as my main gun and a Devilbiss EGA for sunbursts and touchups (and I am appalled when I see the current prices!). Both conventional siphon feed. But there is a lot of good equipment out there, and I'm sure there are advantages and disadvantages to gravity feed and lower pressure guns. The thing is to do it with your equipment until you have your system working for you.

There can be things wrong with the gun that mess up the spray pattern. Guns need parts replaced regularly. The manufacturers all explain how to troubleshoot. If your gun was previously used, it may need some rebuilding. This is easy and you can do it yourself with the right kit. Spray guns are fairly simple devices, but they are very sensitive.

[charles Tauber]

Originally Posted by Howard Klepper

The Devilbiss Plus is not an HVLP gun and not a "conversion" gun.

Ah. Quickstep, you need to understand what equipment you have and how/if it works together. A regular high pressure, low volume (HPLV) gun simply will not produce anything approximating acceptable results if used with, for example, a high volume, low pressure (HVLP) turbine. HVLP equipment is often in the 5 to 10 psi range while HPLV equipment is often in the 40 to 100 psi range. Different animals, very different behaviour.

[Tom West]

I use a Turbinaire HVLP outfit. I hate finish work, don't do much and think for folks that don't do much finish a turbine HVLP system works very nicely. They are easy to use, don't take up much room, easy to maintain and reasonably priced. There are quite a few companies producing systems so there is a nice selection.
Tom

[mirwa]

Wow so many replies to the poor guy, and so confusing even for me to read.

Any spray gun is good for the job, you just need to learn how to use it.

Back in the 80's high pressure spray guns were the common thing and majority of them were suction fed.

Nowadays 90 plus percent of the spray guns on the market are HVLP, High volume low pressure. You can run these at pressures upwards of 60psi with good results, I run most of my spray guns down around 28psi.

Pull the gun apart, clean it thoroughly, experiment with the different controls

Steve

[Quickstep192]

"the pattern is adjustable; do you know which knob does that? It's usually the one off to the side, or on the top center. It controls the airflow from the side holes in the nozzle. The lower knob in the center is for fluid flow."

Yes, I know that. I can't seem to get it dialed in to a narrow pattern though. When it's narrow, it seems like it's not well atomized. When I widen it out, the atomization seems better, but then it seems too wide. If I reduce the fluid when the pattern is narrow, the spray seems too dry.

I found the specs in the attached link online. As I suspected, there's only one air cap and it appears from the documentation it's intended to spray a 12" pattern.

http://www.autorefinishdevilbiss.com...specifications


I have been trying to spray waterborne, but I think I'm giving that up.

[mirwa]

Have you got photos of your gun, just so we are all on the same page, or a link to a website that shows your particular gun.

You should have a number written on your aircap, what is it? remove the cap and look at your nozzle what number is written on it, what type of compressor are you using, what length of hose, are you regulating pressure at the gun or at the compressor

Waterbased paints are different to spray than something like nitro, if your painting clear then its very difficult to actually see the paint, as its being applied.

Steve

[charles Tauber]

Originally Posted by Quickstep192

I found the specs in the attached link online. As I suspected, there's only one air cap and it appears from the documentation it's intended to spray a 12" pattern.


I have been trying to spray waterborne, but I think I'm giving that up.

And, it requires 9 to 11 CFM at 30 to 40 psi. You'll need a pretty good sized compressor to achieve that. At less than that you won't get a very good spray pattern with good atomization. A 12" pattern isn't going to work well for guitars.

Waterborne or not wont make much difference in this situation.

[Quickstep192]

Originally Posted by charles Tauber

And, it requires 9 to 11 CFM at 30 to 40 psi. You'll need a pretty good sized compressor to achieve that. At less than that you won't get a very good spray pattern with good atomization. A 12" pattern isn't going to work well for guitars.

Waterborne or not wont make much difference in this situation.

Never thought of the compressor as the culprit because it doesn't seem to have trouble keeping up, but maybe that's not enough?. I'm regulating pressure at the gun using the Devilbiss regulator. I'm using about 20' of hose with a separator at the compressor and a separator/filter at the gun. I have tips from 1.2 to 1.6. I was using 1.4 on the waterborne, will switch to 1.2 for nitro. It comes with the 410 air cap and I believe it's the only choice.

When I bought this, they called it a HVLP conversion gun. Now they call it a high transfer efficiency gun. Here's a picture.

http://www.tooltopia.com/_img/DEV/DEVGFG670.jpg

[B. Howard]

I use a Devilbis SRI pro, it is a gun designed for automotive touch up, a spot repair gun. It works great on small objects like guitars. As stated proper set up and technique make all the difference in the world. Here is a link to an article I wrote on setting up a gun and spray technique specifically for guitars.
http://howardguitars.blogspot.com/20...-by-brian.html

[charles Tauber]

Originally Posted by Quickstep192

Never thought of the compressor as the culprit because it doesn't seem to have trouble keeping up, but maybe that's not enough?

My "1 horsepower" compressor is rated at 6.5 CMF @ 40 psi: it wouldn't properly drive your gun. Look up the specifications for your compressor: most will have a badge attached to the compressor that states air flow @ psi. Other than tank size, that is the specification that practically matters.

I'm regulating pressure at the gun using the Devilbiss regulator.

At what pressure are you regulating the air?

You aren't likely to have better success switching from water-based to nitro. They are different, but you still need to get the equipment sorted out to obtain good results, regardless of which you spray.

[mirwa]

Thanks for the links, your gun looks fine, I believe the issues are you need to dial it in a bit better.

If the tank has a reservoir then don't stress about air delivery in cfm, just means you may have to stop every now and then and let your tank catch back up.

Water base paints I use a tip any where from .5 - 1.0, and I usually thin the paint out 10 percent, no more.

Are you putting in a dye or pigment into your lacquer to see your spray pattern a bit better, I would recommend this whilst dialling it in.

Also spraying is not just aim the gun and pull the handle full, I very rarely if ever open any gun up to full flow

As a start, knock your pressure down to about 26psi, to do this detent the gun to first trigger position and hold the air on, adjust your regulator until you get the desired air pressure. Spray a tinted lacquer at a surface and adjust your air feed down until you are making a big spot on the wall, slowly wind it the other way until you get your oval shape.

Let us know what the spray looks like on a straight pass having done this and we can walk you through to the next step

Steve