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Discussion Starter #1 (Edited)
Help with my sprayer setup

I am fed up! I have researched and researched, even bothered some of you guys about getting my gun to spray correctly. AND...researched even more. I shot a quick video with my phone showing you what I am working with and I hope that someone can help me avoid the orange peel.

The compressor is 6.2 CFM @ 40 psi, you can see the full specs here (pg. 8) http://manuals.harborfreight.com/manuals/67000-67999/67708.pdf

Here is the link to the video....please let me know where to go from here.

Thanks a ton!
 

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Your compressor won't be the problem with orange peal unless the pressure starts dropping below 40 psi. I'm unable to watch the video. Every gun is going to work a little different. I have a harbor freight purple gun and I have to thin the finish more than I would using one of their siphon sprayers. If the gun has been thoroughly cleaned then the problem has to be with the paint. It either isn't thinned enough or the paint is drying too fast. For example lacquer dries really fast and prone to orange peal. In normal weather it is usually enough just to add more lacquer thinner to eliminate orange peal. I normally thin lacquer 40% anyway. In really hot weather it's sometimes necessary to add retarder thinner to the finish to slow the drying time enough it can flow out. When spraying the inside of a cabinet it is really prone to orange peal especially in the corners. I prefer to use a pressure pot sprayer to finish cabinets with for that reason.
 

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Discussion Starter #3
Thanks Steve! Not sure why you cant see the video....hope others don't have this issue, if so, I will find a fix.

Wow, 40% huh? Well, I sprayed with about 20% (5 to 1) thinning. It is very hot here in Houston....and humid. Also, when I turn on my ventilation, it sucks the air from the ceiling and turns the room even hotter.

The paint is pro classic (SW) oil based enamel. I am making some small fixtures that will be installed in a bathroom, this is why I am staying away from any waterborne finishes. Also, as you replied in a previous post of mine, the waterborne stuff was way to thick.
 

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Thanks Steve! Not sure why you cant see the video....hope others don't have this issue, if so, I will find a fix.

Wow, 40% huh? Well, I sprayed with about 20% (5 to 1) thinning. It is very hot here in Houston....and humid. Also, when I turn on my ventilation, it sucks the air from the ceiling and turns the room even hotter.

The paint is pro classic (SW) oil based enamel. I am making some small fixtures that will be installed in a bathroom, this is why I am staying away from any waterborne finishes. Also, as you replied in a previous post of mine, the waterborne stuff was way to thick.
I'm on dial-up internet and can't get any video.

I can't believe you are having a orange peal problem with enamel. The only thing you can do is keep adding mineral spirits to the paint until it sprays well. Now oil based is different than lacquer. It's best not to thin it any more than you have to in order to get it to spray. If you over thin it, it screws with the sheen and much more likely to have runs.
 

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Discussion Starter #5
I'm on dial-up internet and can't get any video.

:laughing::laughing::laughing: Dial up.....what is that? Just kidding man....thanks for the replies. The video just shows my compressor and filter setup. I am also using the Harbor Freight special (gun). Thought that might be my issue, but I bet your right about the mixing issue. When I clean my gun (running the right thinner through it) it really atomizes well. So maybe just thinning will help.
 

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I used a lot of lacquer and enamel in the body shop I used to have..... Orange peel is caused by not thinning enough..
Lacquer is especially sensitive ..... Keep thinning until you get the results you want.... Just be careful of running....
Your setup is fine... But don't go above 40 psi....
 

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At that pressure your lacquer is probably drying to fast, like drying in the air and then hitting the work surface. I have to spray in SW Oklahoma and the heat can be a killer.
I will add some retarder to extend dry time, also you need to be using sanding sealer before applying the lacquer.
 

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Your video did not show the gun very well. I see a myriad of problems with your set up. First you have a meandering hose as output from your tank without the options for draining out the water.

The regulator on your tank can be set at 90 PSI, A filter at the tank is pretty useless, as the output pressure produces blow by the filter.

You should or only need one filter, and that would be a disposable bulb filter on the handle of the gun. Attached to that a small regulator, and gauge to let you regulate the air to the gun to whatever pressure you want.

As for spraying, your oil base finishes will be difficult to spray, as they are heavy bodied. They need to be thinned, and it's difficult to keep them from running.

Lacquer, depending on the type can be thinned quite a bit. When I used it I thinned around 50%. Your orange peel is likely from your not getting enough lacquer on and keeping a wet line. If it's drying too fast, you'll get orange peel. Attributing to the fast dry, is if you are spraying too far from the subject, or moving too slow, or both. Some of the orange peel can be minimized by changing the pattern of your spray. If it's too wide, you will have a problem getting enough to lay down. Condensing the pattern will produce a more concentrated output.

There are different lacquer thinners. A real paint store, will carry a slow...medium...and fast dry thinner. There is also a lacquer retarder, which will slow down the dry time. So, just thinning lacquer may not solve the problem sufficiently, because a fast dry thinner could be the problem.

Now, getting back to your set up. The picture below is a general idea of what you can do in a small area to set up a spray system. Make note that it provides for an uphill, and then a down hill direction to allow condensation to collect, and a way to drain it off.

EDIT: You can increase the output of the gun by turning down the pressure, and increasing the fluid flow. Practice the settings.
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aircomp.jpg






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Discussion Starter #9
Thanks Cabinetman...

You can see the specs on the gun here if that is what you were after, but I have a suspicion that you would be interested in the settings I had on the gun. Fan pattern - about 1/4 of the way out (from tight); Fluid is almost wide open and Air was almost wide open.

Two days ago I was spraying some paint and noticed an unusually large amount of water in the bulb filter (at the gun). It was about 1/4 full of water! It is very humid here and that end of my shop is not insulated so I am at the mercy of the weather. Also, when I turn on the ventilation, it sucks all the hot air down and it is like an oven if I spray in the middle of the day. I try to only do it at night, but not always an option.

The reason the bulb filter is in the ceiling above the spray area is because the project that I am working on is assembled and I need to get in tight spaces. I will post a pic in a minute of this project, because it is what I am going to put the oil based on and I would like your opinion before hand...I can still change gears at this point.

Eventually, I will put the two drain traps and change from hose to pipe. I had to have a solution in a hurry. The reason I used three filters, is because it seem to be logical to me from what i have read. The oil/dirt filter (the first one) doesn't remove water very well. The second filter is made just for water (from what I read). The third is just a small disposable to catch anything at the end of the run.
 

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Thanks Cabinetman...

You can see the specs on the gun here if that is what you were after, but I have a suspicion that you would be interested in the settings I had on the gun. Fan pattern - about 1/4 of the way out (from tight); Fluid is almost wide open and Air was almost wide open.
I've given you my opinion on the set up. I'm in a very high humidity area. It can be 50% in the morning and 99% by 2 P.M. The airline as you have it will just collect moisture. You have to experiment with the air pressure and fluid amount. You said the fluid and air were almost wide open. If you experiment with cutting the air pressure at the gun and increasing the fluid, you can get good (or better) coverage to keep orange peel down. This may work for lacquer, but, for spraying oil base the adjustments will be different.

So, experimenting and practicing will give you some experience on how to adjust the gun.






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Discussion Starter #11 (Edited)
Here are the photos... It will go in a bathroom and this is why I wanted to use oil based....from what I have read it is the way to go in humid environments???? I never assemble before I put a finish on, but this thing needed a LOT of glue and wood putty, so I thought that I would give it a shot. I could put it on by hand/brush, but I have another project that I am about to start that will be in a very humid bathroom that a sauna and the customer requires a very clean and semi-gloss white. So I am using this project as my learning curve. The bottom image is a render of the 3d design I made for her.
 

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As busy as that shelf unit is you really need a pressure pot to spray that. It takes too long to spray with a cup gun especially if you have a gravity feed gun. Anyway I would attach some wood to the top and bottom of it so you can quickly rotate it around on horses to spray it like I do with finishing interior doors. You could come back later and touch up the top with a brush. If you had it suspended on horses the overspray would go on past the shelf but you have it sitting on a flat table on paper and it is more likely to have overspray blowing back and sticking in the finish.
 

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Rick Mosher
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Part of your problem is the inside diameter of your air line. Looks like 1/4" and it should be 3/8". HVLP stands for High Volume Low Pressure, the 3/8" airline allows more air volume so better atomization.

Orange Peel is caused by viscosity, so in other words your paint is too thick for the tip you're using. A 1.8 tip is great for lacquer thinned to 19 to 20 seconds in a #2 zahn cup. You can thin that lacquer up to 100% to get it to spray properly. The hotter the weather the less thinner you need.

For oil based paint you will need a larger fluid tip, a 2.8 to a 3.0 would be about right. Then your gravity cup will spray just as fast as a pressure pot. For oil based paint atomization isn't as important due to the slow drying rate, spray it on at a low air pressure with high fluid coverage and let it flow out on its own.

Do some samples and experiment with different reductions using the lacquer you have and I think you will find a sweet sopt that you can use every time for great results. Lacquer does need to be properly atomized due to the fast drying time. Cheap viscosity cups can be found at most good paint stores or online.

 

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Discussion Starter #15
So, from what I am learning, the drain(s) are really all that i am missing from my setup? Makes sense to me, and it gives the air time to cool before it hits the filters, leaving most of the condensation a victim of gravity, got it :thumbsup:

Not part of my original post, but I just have to ask (and maybe I am misunderstanding HVLP) but what do all the pro cabinet guys do for bathrooms? From what I am told, there really isn't anything I can run through the tip of my HVLP.....Well.....lacquer thinned to 40%. I can spray stain and dye mixtures with ease. So when I take on a job for something in a humid environment and I want it to last, what should I use and is there ANYTHING that will work with my setup?


Thanks...:blink:
 

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Rick Mosher
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I spray everything from stain to polyester primer with my gravity cup with no problem. Just a matter of using the proper fluid tip to match the viscosity of the paint. Professional finishers pretty much all use a Kremlin Air Assisted system these days, pressure pots are old technology. ( I still love them though)
 

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That compressor is way to small to keep up with a HVLP.
What is the CFM and PSI specs for your gun?
And keep in mind, the PSI requirement for your gun
is measured at the gun with the trigger pulled.
 

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So, from what I am learning, the drain(s) are really all that i am missing from my setup? Makes sense to me, and it gives the air time to cool before it hits the filters, leaving most of the condensation a victim of gravity, got it :thumbsup:

Not part of my original post, but I just have to ask (and maybe I am misunderstanding HVLP) but what do all the pro cabinet guys do for bathrooms? From what I am told, there really isn't anything I can run through the tip of my HVLP.....Well.....lacquer thinned to 40%. I can spray stain and dye mixtures with ease. So when I take on a job for something in a humid environment and I want it to last, what should I use and is there ANYTHING that will work with my setup?


Thanks...:blink:
I personally prefer oil based enamel or polyurethane for bath cabinets however any paint or finish rated for exterior use would work fine also. A nitrocellulose lacquer is one that doesn't do well in wet locations. A cab-acrylic or sometimes called butyrate lacquer is a better lacquer for that application.
 

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I just noticed your specs on the gun,
The gun takes twice the CFM that the compressor puts out,
now that's a problem.
 
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