HVLP Paint Sprayer Recommendations

On Thursday, March 15, 2018 at 10:47:28 AM UTC-5, jfitch wrote:
On Wednesday, March 14, 2018 at 9:06:10 PM UTC-7, LongJourney wrote:
On Wednesday, March 14, 2018 at 9:53:47 AM UTC-5, Tony wrote:
The last few fabric covered gliders i've been involved with have been done with Stewart Systems covering process. They strongly recommend the DeVilbiss Finish Line IV HVLP gun. My previous experience was on cheap HVLP guns from NAPA auto parts or Harbor Freight. I recommend the DeVilbiss Finish Line IV.

Thanks, Tony. It looks like the DeVilbiss is standalone? I see good reviews of it, but I'm kinda looking at some of the $200 range HVLP guns that come with a compressor and a long length of hose. Our big standard air compressor always has a bunch of water in it, and even decent filters only do so much.

I know that the HVLP compressors heat the air more than desired, but I've read that a decent length of hose will help cool it. I'm using Poly-Fiber, and plan on adding reducer to help counter the heat, as well. I have read that it's best to stay away from the Harbor Freight HVLP tools, as they don't deliver an accurate pattern and fail after a short life.

Again, thanks for the help!

Jeff

A refrigerated air dryer can fix almost all moisture problems. You can find small ones on ebay frequently for not a lot. I have a 5 hp compressor running pretty much all day feeding the CNC machines, tried all kinds of filters without much success, after installation of the refrigerated dryer everything downstream of that is bone dry.

Thanks. Is a refrigerated air dryer electric? Not that that is a problem, I'm just not familiar with the device.

Jeff

Yes it’s a electric powered refrigerator.

For years I kept adding filters and drain traps, but kept spitting water droplets after spraying for a while. Finally figured out that when the compressor is working hard, the moisture is in vapor form and will never get trapped in any filter or drain, but when the pressure is suddenly released at the spray nozzle the air is cooled and water droplets form..........same principal as your refrigerator works on. The best long term solution is a refrigerated air dryer if you want to spend $500 or more. There are desiccant systems available for less, that do the job, but require constant monitoring and changing the desiccant. Harbor Freight stuff is too cheap, but I find guns for $65 to $100 bucks work quite well. A good painter is constantly monitoring flow, fan and pressure. In fact when approaching an area where excess paint may cause a run, I simply lower the pressure that reduces the amount of product I'm applying without the need to adjust flow or fan. Good lighting is a must as is a very clean spray area.............one bug will ruin all the prep work!
Cheers,
JJ

One of our club members fabricated a nifty water quencher. He had a coil of copper tubing made that fit nicely in the bottom of a 5 gallon bucket. Compressed air was routed through this tubing, which sat in the 5 gallon bucket, buried in ICE. At the end of the copper tube was a big water trap and then the line going to the paint gun. All that hot humid air coming out of the air compressor was cooled down, any moisture condensed and then trapped. We also put an inline trap at the gun. Same philosophy as the refrigerator water trap mentioned.

Stewart Systems does not recommend Turbine systems, this was tested and found to be true by another club member. It is also a water borne paint system, and as such is incredibly sensitive to moisture in the line. We have learned that the hard way on the three gliders (So far) that i've been involved in refinishing with the system.

On Friday, March 16, 2018 at 2:38:34 PM UTC-7, Tony wrote:
One of our club members fabricated a nifty water quencher. He had a coil of copper tubing made that fit nicely in the bottom of a 5 gallon bucket. Compressed air was routed through this tubing, which sat in the 5 gallon bucket, buried in ICE. At the end of the copper tube was a big water trap and then the line going to the paint gun. All that hot humid air coming out of the air compressor was cooled down, any moisture condensed and then trapped.. We also put an inline trap at the gun. Same philosophy as the refrigerator water trap mentioned.

Stewart Systems does not recommend Turbine systems, this was tested and found to be true by another club member. It is also a water borne paint system, and as such is incredibly sensitive to moisture in the line. We have learned that the hard way on the three gliders (So far) that i've been involved in refinishing with the system.

A refrigerated air dryer will cool the air to about 40 F, lowering the dew point to at least that by condensing the moisture out. The air is then passed through the condenser, elevating it back to room temp or so, now relative humidity will be quite low. The bucket of ice will do the same thing (for awhile) but you want keep from having a low spot in the coil of tube, a bit of a problem to work out. The reason is that water will condense and puddle in the low point at low air flow, they blow through in a slug when air flow increases. This is the same reason you want the air lines overhead, rather than under the floor. I've had to abandon the air lines under the floor of my shop for this reason.

If you look for a little while, you can get a refrigerated air dryer on ebay for about $200.

On Friday, March 16, 2018 at 6:51:50 AM UTC-7, wrote:
one bug will ruin all the prep work!

That's what you get for painting the glider after it's built. We paint them before we build them, so the bugs end up on the inside.

--Bob K.

I’ve been using a $200 HVLP knock off for years for Polyfiber and Ceconite. No complaints at all. Just make sure your air is dry. I just have a drop down drain for water and drain my compressor regularly.

The Wix Aquachek spin-on desiccant filter looks promising for intermittent use. Around $100 for the installation kit and one filter.

On Thursday, March 15, 2018 at 10:50:15 AM UTC-4, wrote:
I use a cheap HVLP gun from Home Depot and throw it away after a few jobs.

I've gotten a lot of good information from an Aussie that calls
himself The Gunman and posts on YouTube. Here's his take on buying
(or not buying) a cheap spray gun:

https://www.youtube.com/watch?v=YHylD3Tb_zU

Sounds like he's largely in agreement with you. He has other
videos reviewing specific guns. And he's got that great Ozzie
accent.

Jim Beckman

On Friday, March 16, 2018 at 6:51:50 AM UTC-7, wrote:

...Harbor Freight stuff is too cheap

For final finish, maybe. But I've found that the standard $16 purple gun ($10 when on sale) is perfect for spraying the vinylester we use as an in-mold primer instead of gelcoat. I generally get three good sprays out of them, and then relegate them to backup duty or the parts bin.

For the polyurethane topcoat, the auto body shop down the road uses whatever they use. Probably pricy.

--Bob K.