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After going back and forth on compressor or turbine system, I decided to go with a compressor/gun, and picked up an Iwata LPH-300 with the 1.3 tip, dryer/filter, and regulator from TCP Global. I have everything ready to start spraying and learning, but I need some help setting up the gun. I thought it would come with some kind of graphic detailing what things were, but no cigar.

These are my questions:

1) I'm not sure what this dial is, or how I should set it.

2) Closing this down decreases the trigger pull, which I assume controls the fan size?

3) Controls the air? I set the compressor to 90 PSI. The gun atomizes at 15 PSI, which I set at the regulator. Should I leave this one wide open?

4) If my pressure's off by one or two PSI, is that a big deal? The regulator doesn't have the most exact layout.

James, if its like mine, one controls volume of material and the other fan size. I was under the impression that around 32 lbs was optimal for spraying - at least that is what works for me.

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Rich Smith
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#1 controls the fan air supply - you want to set this before you set your main air pressure

#2 controls the max needle 'depth' or whatever you want to call it. i.e. it controls the amount of atomized fluid coming through the tip.

#3 controls the air pressure.

I'm still figuring out the relationships with pressures/finish quality etc. The one thing I do know is that you want your tip pressure to be figured with everything running under spraying conditions. e.g. if you set your pressure at 15psi and then adjust your fan pressure, your tip pressure will change.

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Hi James,

Go to the following, hope it helps.

http://www.anestiwata.com/pdf/W300-G.pdf

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Dean

James,

Allen Macfarlen has posted an excellent "how to" on spraying and spray guns, on the Australian/New Zealand Luthiers Forum. It really helped me to set up my gun much much better. And spraying becomes much easier when you know what all the parts of your gun do.

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Thanks guys. It looks like we know what those dials are for, and now comes the fun part of figuring out how to set it up.

Rod, Allen's thread is great. I just gave it a course read through because of the hour, but I'll comb through tomorrow. Thanks for the link!

Ricardo, I've noticed that a lot of guys like their air set in the low 30's. A few threads on MIMF indicate that, you indicated that, and Allen indicated that. What confuses me is that Iwata notes that atomization starts at 15 PSI for this gun and tip, and Joe White told me a lot of people are using more air because they're used to conventional guns. I'd like to hear more about this to see which pieces I haven't filled yet. I'm brand new.

HVLP conversion guns and conventional guns are two different animals. In a way, I'm sort of glad I started with conventional, but, it took me a while to get used to the lower pressures. I use 29 at the gun, which drops to a listed 10 (I think) on mine.

Of course you know, the setup of the gun is critical. The fact that you have an air nozzle makes it that much more complicated - usually you just have material and fan knobs, with air pressure done with a valve. I started with the air open all the way, and messed around with what I knew - fan and material.

Like Allen, I notched the material knob so I know when I'm 1.5 turns out, or two. The easiest thing to do is start spraying with a consistent mix (or thin). Eventually, you'll reduce 10%, 50% or whatever, then adjust with the air nozzle. This comes in handy when you want to control atomization and affect whether the material is landing on the surface, or bouncing off.

Not sure if this was too basic or not, but just my $.01 (not enough to be $.02 right now).

Don't worry, Aaron, I'm basic at this point

It sounds like higher pressure into the gun results in dramatically lower pressure at the tip? If my gun calls for 15 PSI, is that into the gun or at the tip?

You really want to have a regulator at the gun (like you have) so that you can set the pressure at the gun. Run the compressor at 90-100 psi and adjust at the gun.

I spray with my gun set at 21 psi with the trigger pulled (that's the important detail, with the trigger pulled).

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"There's really no wrong way, as long as the results are what's desired." Charles Fox

"We have to constantly remind ourselves what we're doing....No Luthier is putting a man on the moon!" Harry Fleishman

"Generosity is always different in the eye of the person who didn't receive anything, but who wanted some." Waddy Thomson

<shaking my head> A week of pm-ing back and forth down the dain just kidding

I bought and enjoyed Understanding Wood Finishing by Bob Flexner. It also gives a good (IMHO) explanation of how and why different types of finishes work. With regard to spraying, it explains what each part of the gun does, how and why it works, what atomization is and why it matters, etc. I think it would be worth the purchase, especially since you can buy it used from Amazon for $3.

Does anyone else have a recommendation for books on finishing? I'd love to learn more.

- Flori

I know, Michael. I'd be lying if I said I didn't feel a bit guilty

I called TCP Global today to ask about air pressure. They confirmed that my LPH-300 is designed to shoot with 15 PSI on the regulator at the gun. "Iwatas are extremely efficient," were the exact words. It was a very helpful phone call. They've all been, and I recommend TCP Global highly.

I experimented by spraying water through it tonight and would like to put some dye in there tomorrow. Allen's series of posts was really good to read. Spraying the water gave me a good chance to see the way the fluid and fan controls work.

To Allen's tutorial.

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"There's really no wrong way, as long as the results are what's desired." Charles Fox

"We have to constantly remind ourselves what we're doing....No Luthier is putting a man on the moon!" Harry Fleishman

"Generosity is always different in the eye of the person who didn't receive anything, but who wanted some." Waddy Thomson

with HVLP the air pressure and fluid volume/pressure mix are vital...an HVLP gun is pushing the margins of working efficiently to work the way it does, so just a tad too little air pressure (and in my case using a pressure pot fluid pressure) can be a big issue...

I always spray a test pattern on a scrap piece of plywood and and adjust settings to make sure the pattern is correct...this correctness means that the pattern is the proper cigar shape...a pattern where there is a blank spot in the middle is too much air/not enough fluid...a heavy center pattern indicates too much fluid/not enough air...

your manufacturer might have included a list of supposed proper fluid pressures and air pressures for your fluid nozzle size and air nozzle...the air pressure they list (if they do) is the pressure you would see on your dial on the gun with the trigger pulled, not static pressure...I find that my setup (Binks Mach 1 SL with a #92 fluid nozzle (1.4mm) and either a 90P air cap or a 100P air cap (according to what I am spraying)) works best with my compressor's regulator set @ 40-50 PSI (for proper 'umph' in air supply), and the regulator on the pressure pot set at ~35 PSI...this results in about 12-13 PSI pass through pressure when the trigger is pulled...I have a digital regulator at my gun do be able to dial things in without having to walk back to my compressor which I keep as far as possible from where I am actually spraying...my fluid pressure is typically set @ ~12 PSI (yes, you are using a gravity feed gun as I notice) which is slightly adjusted according to the viscosity of the mix I am using....the preceding pressures result in a fairly heavy fluid application which I prefer to do as I like to shoot a very wet finish very quickly (this is considered proper paint application....if you don't have a run/sag now and again you probably aren't doing things right)...

also be aware that the longer your hose, the higher you will need to set your regulator at the compressor because you loose SCFM because of friction in the hose...I can get away with using a 5/16" hose but prefer to deal with the extra weight of a 3/8" hose because it supplies just that bit more air volume....

Mike, thank you. I spent some time spraying cheap waterborne from Lowes this weekend in order to get some real world experience before practicing with my more expensive lacquer. It was good to shoot something other than water. What type of fan size do you prefer?