What's your Spraying set up?

Hey all, I'm close to finishing my first build and have been looking into a spraying set-up. I asked a friend who is a professional furniture builder and has years of experience in finishing and specialty painting and he actually highly recommended the $15 HVLP gun from Harbor Freight. I just happened to be headed there that day so I went ahead and bought one to hook up to my compressor and was excited about the very low cost of having a spraying set up... I actually bought the same gun that came with the attached regulator for around $29, and along with the needed filter, etc. I am in about $40... then I realized that my wee pancake compressor does not have a suitable CFM to make this gun work well. The gun requires 12 CFM at 40 ish PSI, my compressor is 2.5 CFM at 90 PSI. Even compensating for the different PSI, I don't think it will do the job. I looked into all the hacks to use HVLP with an undersized compressor and it essentially just meant more money (that I really don't have), and I don't want to mess up the last step on a project that I have spent as much time on as I have.... That being said, in an effort to go ahead and finish this instrument the way I want to (Oil varnish), I am back to brushing it on.

However, I am sure this will not be the only instrument I make and I also fully recognize the benefit of being a woodworker with an adequate spray rig, SO, I am considering purchasing an affordable turbine driven HVLP system. The same friend above also said the turbine system at HF is decent (https://www.harborfreight.com/high-v...kit-44677.html), but I have also looked at the Wagner Control Max system that is available just about everywhere (https://www.homedepot.com/p/Wagner-C...8080/207073102) and it seems promising. But my lack of experience has me uncertain. Are either of these suitable for spraying varnish or lacquer well enough for instrument building?

What do you use that you like? Any recommendations for me?... Just love to glean from the collective knowledge of the builders here!

Thanks in advance.

I've been spraying HVLP for over 30 years, hundreds and hundreds of gallons of lacquer, and a lot of other products. Not much varnish through the spray gun. That's a challenge. I have a couple AccuSpray guns. They're top notch. One is attached to a pressure pot, the other is a cup gun. I have a couple other guns, DeVil Biss, and I think a Sharpe. You can't cheap out on the gun. It will suck.
As you've discovered, HVLP stands for high volume low pressure, and that high volume part can't be overstated. I started with a turbine unit, an Accuspray, and actually burned that up because we were running it all the time. I knew my smaller compressors weren't up to the job, so I went to Farm and Fleet and bought an upright big tanked aluminum-headed compressor (big tank). Burned that up in no time. Aluminum head couldn't take it. Compressor was running constantly until it didn't anymore.
So I'm running a huge steel compressor with probably a 75 gallon tank. It can keep up with whatever I throw at it. It's like what you'd see at a service station. I got a great deal on it. It's probably 25 years old. At least. I think I only paid $250 for it, but it should have cost at least $1k, in its used condition.
If you're only spraying instruments and such, a turbine should work fine. They take a little getting used to. The air gets hot from the friction in the turbine, so you have to adjust your viscocity and you may need to add retarder to lacquer or you will get orange peel. Among other things.
I wouldn't trust those units you referenced. They're aimed at DIY'ers where standards and expectations are far different than what you want to see on an instrument.
HVLP is wonderful and you can spray into places you simply can't otherwise because of the air pressure and the tornado effect. But if you want quality, you can't cheap out.
My two cents worth.

Any thoughts on LVLP?

Just researching a little and found that LVLP can run on a small (even a pancake) compressor. It seams like it would be suitable, am I wrong?

I don't know much about the LVLP equipment. My hunch is that there's going to be a lot of compromises. To get the quality we'd expect on an instrument, you're going to have to thin the material a lot and add some retarder or you're going to get orange peel. You simply aren't going to get the atomization you need, unless you crank the air pressure up to where it isn't low pressure anymore. You can always do that, but then that changes the whole process. One of the most important things when spraying any finish is atomization. You can't have big droplets coming out the end of the gun.
You know, you could go to a Sata detail gun, HVLP. Because it sprays a smaller amount per second, it doesn't require near the volume of air and you might pull it off on a smaller compressor. I don't think a pancake would cut it, but something with a larger tank (15 gallon or so) might do it. I have a Sata and sometimes use it on mandolins and for touch up work.
Another thing to keep in mind with HVLP and a compressor: you're going to have to be mindful about draining your compressor for water more often simply because it's running a lot and condensing a lot of moisture into the tank. If you don't, you'll have blushing problems, in addition to all the other marvels that good finishing entails.

So there's a whole other thing going on here:

HVLP conversion guns: run off a compressor

HVLP (true hvlp): run off a turbine

True HVLP is essential for cabinets and stuff, virtually no overspray or bounce-back and a different technique in general than spraying conventional. You don't go for a gloss finish, you spray down orange peel and let lit level. I sprayed a couple dozen mandolins with true HVLP in waterbased finishes. I sprayed all my laquer finishes with conventional guns.

Now I use conventional whenever possible, just for convenience, but when I need to do cabinets, house projects and stuff I use the turbine rig.

Doesn't really matter what you use. It'll be a pain in the butt until you've developed your process with it, and then you'll know how to do it.

I finished this mandolin in $9 Minwax poly and an airbrush. It worked fine.

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Bleh!... I've always hated finishing ... :crying:

Then... don't. Do a Maloof finish or something and call it a day. A simple finish is better than a bad or half-hearted attempt at a full gloss finish (one of which is in your possession, and I did it, haha). So many people ruin their decent craftsmanship with crappy finishes just because they hear "it's gotta be lacquer" or "it's gotta bit Pratt & Lambert #58" or whatever. You're a pro woodworker, use what you know works.

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Originally Posted by soliver

Any thoughts on LVLP?

Just researching a little and found that LVLP can run on a small (even a pancake) compressor. It seams like it would be suitable, am I wrong?

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I got a nice LVLP set up from Homestead Finishing a long time ago for the same reason. They have some nice Taiwanese made guns for $200-$300. For lacquer, you're going to want a 1.4mm tip/cap. A small touchup gun is really enough for finishing mandolins, but if you think you'll move on to guitars or furniture, then a full size gun would make more sense. In rereading Dale's post, I can tell you that LVLP is not a compromise for smaller items. You don't "thin" any more than standard and can achieve fine full wet coats just by keeping your passes closer to eachother (which you'd also have to do with a cheap touchup gun). You will need reducer or flowout enhancer for whatever finish you're shooting. Also, you need a full face mask with VOC rated cartridges, you can quickly do irreparable damage to your lungs with nitrocellulose lacquer.
*full disclosure, I also do cabinet work and now have a 60 gallon compressor and recently broke down to buy a gun that was over $500, so spraying can get very expensive.

Alternately, Harbor Freight sells mid-sized, oil cooled compressors for <$200 that might produce the CFM you need for the gun you have, especially considering you're going to dial the pressure back to 40 PSI max.

Good luck in the adventure. Spray guns are a whole new experience with a learning curve. With practice you can get great results, WAY cheaper that rattle cans. There are lots of resources/tutorials on the web to get you started. And of course, practice on scrap first.

For the record and for the benefit of this thread, I use a simple Coleman air compressor, bought used from Craigslist, a Harbor Freight $35 conventional siphon feed spray gun and 30+ years of experience. (Of course I have water traps, air dryers, regulators and so forth.)
I've used HVLP, I've used expensive fancy guns, I've sprayed "boxes" when working at the cabinet shop, and I've concluded that the operator is the most important thing.
HVLP is no advantage to me because I don't spray boxes anymore, I don't spray enough finish to ever get back the investment in material savings, I don't have to worry about being in compliance with VOC regulations and so forth. The quality of a sprayed finish is largely dependent on good atomization (as Dale said) and that depends much more on the tip/nozzle combination than the gun behind it, and the higher pressure of conventional systems gives excellent atomization. Overspray is not a problem for me in my finish room with the serious exhaust fan that's in the wall.
My favorite system that I've used was a pressure feed system, and one of these days when I feel like I can afford it I will go back to that.

Good thoughts Marty,... Its more that on the whole, finishing is always my least favorite part of the whole production, so ...Bleh.

I'd like to learn the process, (particularly spraying) as an effort at not only doing what might be best* to enhance what I've already done, but also to be able to apply the skill to other stuff in the future. (*by "Best" I mean applying the finish I want to use in an "easier" way)

I plan to do a lot of test pieces and if it doesn't work out, I will reassess.

The good news is that your first effort, a combination of material, equipment, temperature, humidity and planetary alignment, could be very good. The bad news is it can be followed with unlimited frustration, even if everything seems the same. See the related threads here.
Just keep good notes, avoid water and dust, and remember that the mandolin is rather small and can be positioned as needed. Also, add better lighting, as much as you can, as you really need to see what’s going on with each stroke. Your test boards should be the same material as the instrument, prepared, sanded, sealed the same way, or else.

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Originally Posted by Marty Jacobson

... You're a pro woodworker, use what you know works.

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I thought of this a little bit this afternoon while mowing the yard...

1. Thanks for that compliment... that means a great deal from such a talented craftsman!

2. "... use what you know work."... so what I'm hearing is that I should call Chad at Lonestar Painting :)):)):))

Just kidding... your advice is always so appreciated, Marty... let's get past this pandemic nonsense so we can hang out again sometime!

I've done 10 mandolins and used the 15 dollar harbor freight HVLP gun for all of them. It works great and i spray at 40# of pre3ssure. I thin out the lacquer about 3:1 lac:thinner and almost always use retarder especially when it is humid and hot. I usually do 8-10 coats. It will usually have a little orange peel and i rub it out with wet 1500 wet paper lightly and then rub it out with meguiar's 105 then 205 and then polish it with ultimate. It is important to wait 2-3 weeks before ribbing it out. If I do get a blush I spray a coat of almost pur3e thinner and retarder ala a trick taught to me by Dan Erlewine.
Hope that helps.
Rob Lander

Also for the record and for Spencer's benefit, I'll chime in with my own experience and some observations. Like John, I use the HF product a great deal, but the cup over, so-called "HVLP" gun w/reg, like the one Spencer bought. Air-driven guns utilizing a needle valve, fluid nozzle and air nozzle are not complicated pieces of equipment. I began spraying with production guns at age 18, in my 20's I became devoted to Binks No. 7 with a Sharpe no-drip cup and during that time I was spraying finishes mostly on automobiles. When working for Lincoln-Mercury dealerships and the like, getting a great finish is a must.

The bulk of my professional career has been to do with film finishes. At age 30, I switched to wood products: pianos, home furnishings, glass-like conference tables, musical instruments and architectural millwork. Used pressure pots, production guns, turbines, airless sprayers, etc. I tried the HF guns about 20 years ago (I'm 65 now) and found that I could get the same excellent results on the cheap, which was a big plus, as I had employees at that time and was doing tons of finishing work. I found that airless was the best solution for high volume work on panels and cabinets finished in-shop. The HF HVLP was used for most else.

Enough on the past; here are a few observations.

The first observation is that preferences and opinions among talented experts can vary widely. Dale Ludwig must have the best equipment; John Hamlett needs only an HF gun and small compressor. Neither of them is wrong, and both get eye-popping results.

The second observation echoes John: I've concluded that the operator is the most important thing. This holds true for any type of finishing, whether you're using a brush or a spray rig.

Third: The only way to get experience is to do it. I'd encourage Spencer to start by using the rig he already has. It's understandable that you don't want to experiment on your first build with it, so don't do that. Be comfortable. But I can say that it is definitely possible to get a professional finish on a mandolin with the HF HVLP and a pancake compressor. So, may I suggest that you cut out a mandolin-shaped piece of plywood, and learn to get a smooth finish on it front and back?

The best trick is to get a feel for the correct amount of air pressure in order to get good atomization at your particular viscosity, rather than relying on charts you find, or advice from forums. And the eyes to see just how wet you can spray it on while avoiding runs. These things come with some experience, so if you want to learn to use a spray rig, just get started with what you already have.

Thanks Mark... Just to update this, I have since realized that the HF gun I bought would not work with my compressor. I have ordered a LVLP (Low Volume Low Pressure) gun and will do a lot of experimenting once it arrives... am however going on vacation on the second week of Oct, and hope to have it done by then so I can take it with... we'll see how it goes. Thanks so much fo all the advice everyone. Big thanks for all that info from Mr Gunther, of course!

I just wanted to update this thread. I ordered an LVLP "Touch-up" gun with a little 4 oz cup. I didn't quite research as much as I should have and found out too late it had a 0.8 tip. This is the unit: https://www.ebay.com/itm/SPRAYIT-SP-...7-2e751691be00

Knowing (after a lot of Google time) that a. The preferred tip size for oil varnish is 1.3 - 1.6 ish and b. A good starting point was a 3 to 1 mix of varnish to thinner, I gave it a try with the 0.8 tip and thinned 2 to 1 varnish to lacquer thinner so it would be a little thinner to compensate for the small tip. My test spray with water for the set up worked great.

This little gun is really really easy to use!... I set it up, had the pressure set somewhere between 5 and 10 psi and sprayed a couple of test pieces and I think it's going to do the job. The fan is only about 5-6 inches in lengths and it sprayed on even and thin and looks pretty good so far. I'll let it dry overnight and see how it looks tomorrow evening.

I saved the remainder of my mix of Varnish in a sealed container. Can this be used again, or do I need to pitch it?

Spencer, diluted paints generally keep fine in a closed container. Of course, not two-part materials that can’t be saved. Just remember to agitate/mix and use a paper/nylon filter again when you refill your gun because there might be some settling or clumping. Make sure you solvent clean the gun between uses; leaving the gun ‘loaded’ is not a good idea.
As mentioned, dilution and pressure are variables you can control, so that equipment details do not have to be exact (tip size, for example). The issues with nominal excessive thinner are runs (spray horizontal when you can), and the thinner softening undercoats, which is sometimes good, sometimes bad.

Much appreciated Richard. If things look good on my test pieces this evening, I'll spray a first coat and share pics.

First coat looks good... already had a little dust infection, but I think I can sand it out... I'm thinking if I can control the dust, this may turn out nice

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