Question about getting started with HVLP spraying...


Dolmetscher007
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I am very much a hobbyist and very much have a hobbyist budget. I have seen a lot of videos on, "Getting started with HVLP," and some of them are great. But... there are three aspects of an HVLP system that I'm finding difficult to parse out. 

  1. Air compressor size and specs
  2. Connectors between different air hoses and components
  3. Nozzle size

I have no aspiration to some day be spraying dozens of pieces all throughout a day. My needs are incredibly small. The largest thing I'd ever need to spray might be a book case... and even then, I'd only spray something once or twice a month max. So, I am pretty desperate to keep my investment as low as humanly possible. I already have a small Bostitch pancake air compressor for shooting brad nails. I recently bought a 3rd party attachment so I could also use this tiny compressor to inflate my car tires when they get low. It worked like a charm! The compressor did "kick on" very soon after I began filling my tire(s), but that is fine with me. Even if I have to spray just 2-3 passes and wait for the compressor to recover... that is fine with me as well. Time in not my enemy here. I looked on the internet for "Best HVLP spray gun 2020" and I found this gun listed as the best for the money.  It costs only $40, and for $58, I can get a water/oil separator and some paint/finish strainers. It does not come with a hose. 

So, going back to the two items listed above...

  1. Is this air compressor capable of running this HVLP gun?
  2. Would I need to buy some kind of coupler to attach my existing air hose... to this water/oil separator?
  3. This same gun comes in 1.3 mm, 1.5 mm, 1.7 mm, and 2.0 mm. I will mostly be spraying common latex paint and oil-based alkyd paint. I'd also like to be able to spray lacquer and polyurethane (oil-based and water-based). I cannot tell which size nozzle would be the "happiest of mediums" for spraying all these materials. 

Thanks for all your help guys!

 

 

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I'm going to say "no", based on the 4.5 cfm requirement of the gun and 2.6 cfm capacity of the compressor. Although the compressor might supply near that volume at 40 psi vs. 90 psi, it will run almost continuously.

For spraying paint, I recently purchased a Wagner HVLP unit from my local big blue store. This one has the turbine mounted in the gun, so is compact but a little heavy. For a bit more money, they offer one with a separated turbine system, very similar to the popular Earlex unit. The nice thing about the turbine powered sprayers is that moisture in the line isn't an issue, since they don't compress tge air enough to cause condensation. 

The unit I have came with a second cup/nozzle assembly, meant for spraying clear finishes. I have not used it yet, so can not offer an opinion.

This is the one I have Flexio 3000

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Matt Cremona just used this to spray 2k Urathane on his trailer and said it worked well even though the material was wrong for the gun tip size. I'm pretty sure he said in one of his posts that the hvlp is an erlex machine with rockler's name on it. So you are getting something decent. https://www.rockler.com/rockler-hvlp-finishing-sprayer

I think you'd be better off with, and get a better finish with, a cheap hvlp. Even though the HVLP turbine kit is a bit more expensive than just the compressor and spray gun you'll likely get finish defects from oil and water even with that small separator. I think Tom King has detailed his air cleaning devices that he found were necessary to run an HVLP and they made a Fuji MM 4 look cheap.

Also you'll get about 10 seconds of spraying before the pressure drops too low which will require probably 60 seconds of recharge. It may not seem annoying but it'll get REALLY old really fast. Chasing uneven results will be the telltale sign and the most frustrating part. As a note a there are 7.48 gallons per cubic feet. Boyles law tells us that your compressor has 2.4 CF of 40 psi air when full. Beings that you can only use about half that until the tank needs to recharge you'd have closer to 15 seconds of air flow time.

Here is my question, I'm not sure how all the conversion guns work, does the trigger control both the air flow and fluid flow? My turbine gun only controls the fluid flow and air is constantly flowing. So if a conversion gun works the same you are going to have to install a valve before the gun that you will have to turn on and off to maintain pressure in the compressor tank. Which by the time you flick the valve on and get your body in position to spray you may run out of air. An alternative to get some additional spray time at the cost of recharge time is adding a larger tank to the system but $$$ and this is where a cheap hvlp really starts to win out.

I spray aggravation game boards a lot and the average time it takes me to put 1 coat on an 18" square is about 4 min. That's with a turbine and continual airflow. If I had to work in 10 second increments with a minute of recharge spraying the same item would take me almost 30 min. Assuming 10 seconds of spray and a 60 second wait for recharge.

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2 hours ago, Dolmetscher007 said:

Even if I have to spray just 2-3 passes and wait for the compressor to recover... that is fine with me as well.

Probably not for long. You want to be able to maintain a wet edge when spraying (or rolling, or brushing) and that won't be possible if you're having to wait for the compressor to build pressure.

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Just this year I started spraying my projects where I can. Like you, I don't spray a lot; perhaps 2-3 projects per year. So, I didn't want to invest lots of money and I wanted something that worked with my smallish compressor. While looking for the "best" spray guns, I came across LVLP (low volume low pressure). These guns work with low volume and low pressure compressors and I find them to be perfect for the work I do. The Sprayit brand is a place to start for comparison. These are inexpensive but, I find that they do a really good job. The two I have work with only 4.2 cfm which corresponds to pretty small compressors. Unfortunately, a web search for LVLP spray guns will be somewhat frustrating as it will also turn up lots of HVLP guns as well. Just watch the specs.

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8 hours ago, Tpt life said:

Might be nice to know what finishes you have sprayed with that LVLP setup. 

I have sprayed quite a bit of WB poly and shellac with the 1.3 and 1.5 tips. I don't have professional level experience but, I think it does a very nice job. I have another gun of the same model with a 2.0mm tip that I use for latex. All it takes is some moderate thinning and a little Floetrol to get a nice finish. I'm using a California Air 10 gal compressor w/6.4cfm capacity and i usually have the pressure at the gun set to about 20 psi; higher for latex.

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