HVLP

The dreaded and daunting hvlp. The most difficult part of spraying a finish is getting past the fear of actually trying. There is information overload out there (as well as bad info) that is enough to scare anyone away. Hopefully after reading this article you’ll have enough confidence to get out there and give it a try. Here is a link to the video explaining the basics of the process:   Video,  Read below for more info,

The spray gun:

We have already decided that trying is the hardest part right? Now that we are past that let’s talk abut what you actually need to get started spraying a finish. The first thing obviously is a spray gun, there is everything from the cheapo guns at harbor freight all the way up to the crazy expensive stuff. I would suggest to try and find a nice middle ground, Jay bought a pretty nice gravity feed spray for around 50 bucks. The guns from harbor freight are just too hit and miss for my liking. If you buy a decent gun now, you’ll thank yourself later.

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Here is an example of a good entry level gun, cost around 50 bucks to purchase.

The compressor:

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Here is an example of an acceptable air compressor size, at 20 gallons of air this thing can keep up with your spraying task.

The next item on the list is a compressor, most woodworkers already have one but you need to make sure that yours is adequate. The really small pancake style compressors just aren’t big enough tank wise or push enough cfm’s to realistically think we can use them for spraying.   The smaller the compressor and the lesser cfm’s means the compressor will have a hard to keeping up with your spraying especially on larger projects. If you’ve already got a compressor around this size which most probably do, then you already have this covered.

Fluid tip sizes:

 The next big hurdle is fluid tip size for the actual finish you are going to be spraying. Common sense is to be used here, the thicker the finish means the bigger the tip size your gonna need to spray it. Thinner finishes like shellac can be sprayed through as small as a 1.0 fluid tip. Lacquer, water, and thinned oil based finishes are more in the middle ground 1.5 fluid tip. For the thick stuff like acrylics (thinned), your gonna need a 2.0 or larger. You can obviously use larger tips to spray thinner finishes as well, but you have to be more careful because the larger tip will push more fluid and raise the likelihood of running your finish(which no one wants right?). The thinner finishes(milk paint,water based poly,lacquer, and shellac) are much easier to spray and are more recommended for the typical store bought spray gun. The thicker film finishes aren’t really recommended and most oils are actually easier to just wipe on. One way to measure the viscosity of your material is to use a stir stick. Simply dunk the stick into the material being used, then lift it out and count how long it takes for the steady stream of material coming off the end to break into dripping. For paint, 20 to 25 seconds is where you want to be, and for oil base varnishes, 15 to 20 seconds.

The gun setup:

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There are three basic controls on a spray gun, the fan pattern, the fluid control, and air regulator(some guns have these built-in). The fan pattern is actually quite easy to dial in, the way I recommend is to dial it all the way in to the smallest fan pattern and slowly adjust out until you get a full and consistent spray pattern( I test on a scrap piece of paper or wood). The smaller you set the fan pattern the harder it will be to be consistent and more likely it will be to run. The fluid I usually keep dialed all the way out, the way to adjust is turn the knob all way out and then dial it back in until it starts pushing the trigger forward(you need to be pulling the trigger while doing this). Once you feel it pushing the trigger forward you know the fluid is at it’s largest capacity because it’s at the full extent of the trigger pull. It’s easier to just keep the fluid adjusted out and limit the amount you apply by the speed of which you apply the finish.

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This is an example of a properly tuned fan pattern. You see it’s nice and consistent top to bottom.

The air pressure is the last and probably most daunting aspect of spraying. The suggested air pressure that comes with most guns is just that a suggestion. It’s based on the fact that you have the perfect setup, compressor size, air line size and length, and proper air regulator, which most weekend woodworking shops don’t have. You only need enough air pressure to properly atomize(which means break the paint into small particles) the finish your spraying. I don’t like to rely on the regulator in most cases unless of course you own a high end one. What I suggest is the start out by dialing the pressure all the way down and slowly add more pressure until you can see that it’s properly spraying the finish, you can tell because the finish will spray nice out of the gun and not splattery looking. That’s all the pressure you need for that finish, once you establish what that is, you can use that for future reference with that particular finish.

Applying the finish:

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Make sure to always start and stop your pattern past the edges of your project to prevent puddling.

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The application is the part that takes the most time to get good at, practice is the only way to learn how to properly apply a finish. The simple things are keep the spray pattern 90 degrees to what your spraying and keep your speed and distance(about 10 inches from the surface) consistent. I like to start by spraying the edges first and then the face of the boards next, making sure you are overlapping by about 50 percent on each pass. You want a nice consistent thin film build over the entire project, not too wet and not too dry. Puddles and runs will make the finishing process much harder as you will actually have to sand out these problems before applying another layer of finish.

Cleanup:

This is the part that most folks neglect when spraying a finish on. You must keep your gun clean in between jobs to keep it spraying properly and working the way you want it to. Flushing the gun with some solvents after spraying will help aid in this process. You will also want to take the gun apart and soak the parts in solvent overnight to ensure everything gets properly cleaned. A little gun lube when putting it back together will keep all the parts working properly.

The conclusion:

I hope i have simplified this process for you because that’s really what it is, simple. Once you get used to spraying finishes you’ll never wanna go back to brushing them on. The speed and ease of which you can apply a finish by spraying is really unmatched. All it takes is a little time and practice and you too will be able to achieve nice sprayed on results, so get out there and give it a try, you’ll thank me later 😉

42 thoughts on “HVLP

    • April 10, 2016 at 8:52 AM
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      Thanks Brother!

  • April 10, 2016 at 8:30 AM
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    how about talking about thinning the different products, like oil based gloss paint. and varnish. What viscosity do you thin these products to get good flow out
    Jeff

    • April 10, 2016 at 8:52 AM
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      Most readily available paint thinners and mineral spirits will do the job just fine. It needs to be thin enough to produce a fine mist, but thick enough to get a good application on the surface being sprayed. One way to measure the viscosity of your material is to use a stir stick. Simply dunk the stick into the material being used, then lift it out and count how long it takes for the steady stream of material coming off the end to break into dripping. For paint, 20 to 25 seconds is where you want to be, and for oil base varnishes, 15 to 20 seconds. A lot of it is just a feel for what your spraying, you’ll obviously need a larger tip in your gun and more pressure to spray these. If you test out the spray and seems to still be too thick when trying to spray, simply add more thinner.

  • April 10, 2016 at 8:54 AM
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    Hey Matt,
    You and Jay covered a lot in both the video and the above article. I have been spraying finishes for some time now, but all of a sudden, my gun is leaking shellac, etc. all over the place, my hands, the floor, and vertical surfaces. What am I missing here?

    • April 10, 2016 at 9:48 AM
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      There are a couple of things this could be, the gun needle could need to be cleaned better or it could be sticking and just need to be lubed a little bit. The other problem could be that the seals in the gun are just worn out and that the gun needs replacing.

      • April 10, 2016 at 3:26 PM
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        “lubed a little bit” With What?

        • April 10, 2016 at 7:40 PM
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          They make a spray gun lube that will not interfere with any of your finishes.

  • April 10, 2016 at 10:11 AM
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    Great information, guys. My question is let’s say you are spraying shellac (which dries fast) and you want to spray 3 or 4 coats on a project. If you wait 15 to 20 minutes between coats, can you leave the gun setup like it is, or do you have to clean it immediately?

    • April 10, 2016 at 11:23 AM
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      Shellac should be fine to leave in the gun between coats as long as it’s not left for prolonged periods of time.

    • April 10, 2016 at 2:02 PM
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      I don’t know how well this works for shellac, but when I spray water-based finished, I wrap the gun nozzle with a wet rag between coats to prevent drying out around the needle.

    • April 10, 2016 at 2:02 PM
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      I don’t know how well this works for shellac, but when I spray water-based finishes, I wrap the gun nozzle with a wet rag between coats to prevent drying out around the needle.

  • April 10, 2016 at 10:29 AM
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    Thanks for sharing this. much appreciated.

  • April 10, 2016 at 1:03 PM
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    Hello Matt
    Great job ,I learned a lot and will use it in my work,
    Tell Jay to stand a little further away from you when he videos , he sort of looks like he should be in the Wizard of Oz movie .
    Hey Jay just kidding man

  • April 10, 2016 at 1:54 PM
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    Matt:
    Thanks. Very nicely done!
    A question about water-based latex paint – like you brush onto wood trim. Can this material be sprayed with HVLP and/or an older style conventional gun like a DeVilbiss JGA? If so, how would you prepare it to get it to spray properly? Thanks!
    Bill

    • April 10, 2016 at 7:42 PM
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      Yes, you can spray it but it will need to be thinned and you’ll need a fairly large gun tip like a 2.0 or above. You’ll probably need more air pressure as well to properly atomize the material.

      • April 11, 2016 at 7:52 AM
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        Thanks, Matt. Appreciate the help and thanks again for the video and informative article.

        • April 11, 2016 at 7:29 PM
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          Thank you!

  • April 10, 2016 at 3:17 PM
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    hey Matt i have an graco 4 stage turbine gun. I have tried spraying lacquer but dont seem to get a smooth layout of material not quiet orange peel but almost. love to see a video on spraying lacquer , pigmented and clear. open to any and all suggestions . thanks
    ps. great video

    • April 10, 2016 at 7:43 PM
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      I’m not too familiar with turbine systems but try thinning the finish just a little. Just be careful as the thinner material will be more prone to runs.

    • April 11, 2016 at 9:03 PM
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      Hey mark silly question are you sanding after first coat ?

  • April 10, 2016 at 4:51 PM
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    What about straing the finishes and desacant dryers.

    • April 10, 2016 at 7:38 PM
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      You definitely want to strain everything before spraying it and it’s always a good idea for some sort of water trap to keep contaminants out of your finish.

  • April 10, 2016 at 6:10 PM
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    Ive never used a gun to spray but I wanted to know if it’d be possible to spray a finish like varnish? Is that too viscous of a finish?

    • April 10, 2016 at 7:39 PM
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      Any finish can be sprayed, you just have to find the proper thinner for it. I would imagine with an oil you would need something like mineral spirits or turpentine or something in the oil family.

  • April 10, 2016 at 8:52 PM
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    I have tried spraying oil based Polyurethane on hickory cabinets and it came out great.. Now if I do pine I have trouble with the wood repelling it and I have to sand it down with 300 grit sand paper and then coat again and it comes out fine. Why is this or what should I do?

    • April 10, 2016 at 9:37 PM
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      To be honest, I’m not sure, I have no experience with spraying poly on pine.

  • April 10, 2016 at 9:33 PM
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    Loved the video and article. Just got a gun. It came with a 1.0 tip. From what I gather I’m going to need more tip sizes to change from varnish to poly correct?

    • April 10, 2016 at 9:37 PM
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      You will need larger tip sizes for any of the thicker materials.

      • April 11, 2016 at 4:54 AM
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        Ok. For woodworking finishes only would you say a 1.5 tip would be your choice?

        • April 11, 2016 at 7:30 PM
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          That would be a good size for most finishes!

  • April 11, 2016 at 4:31 AM
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    Matt, for us guys (and Gals) in the more humid states could you talk about water seperators? Right now, I don’t have one. I keep my air tools well lubed. When I use a blow down gun for the parallel surfaces I do see a fine mist coming out that has to be water.

    Thanks.

    • April 11, 2016 at 7:32 PM
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      A water separator is a great idea, when the compressor is running a lot it builds up quite a bit of condensation that will ruin a finish or tool. You can get a fairly cheap separator at a place like harbor freight that you can manually drain the water out of.

  • April 11, 2016 at 8:18 AM
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    Have you used an electric spray gun of any kind?

    • April 11, 2016 at 7:29 PM
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      I haven’t.

  • April 11, 2016 at 9:11 AM
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    Matt I sprayed car finish for 30 yrs. You are right on with your video. I watch Jay all the time. One thing I might suggest with water base clear is , about 1/4 tsp 91% alcohol to a Qt. will break water surface tension and spray better, most straight out of can with out thinning. Don’t forget a respirator and some air flow via exhaust fan.

    • April 11, 2016 at 7:28 PM
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      Good tips man, thanks!

  • April 13, 2016 at 5:26 PM
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    What is a good spray gun to purchase and where do i find one?

    • April 14, 2016 at 8:09 PM
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      The gun used in the video is a kobalt gun from lowes.

  • September 13, 2016 at 8:15 AM
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    So what would be the minimum size compressor you would suggest to use for spraying finish?

    • September 13, 2016 at 9:45 AM
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      I’d say you’d need at least 8 -10 gallons for small jobs. The 17 gallon like they sell at harbor freight would probably be your best option. To be honest though, if you don’t already own a compressor or gun, your best option would probably just be to get one of those self contained turbine units.

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