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View Full Version : Questions on gravity fed, HVLP sprayer



fwb_1234
05-13-2008, 11:47 PM
Questions are bolded.

So, I got this with my compressor, used. It's a central pneumatic (read: Harbor Freight), but it seems that it would be hard to mess up that technology.

Anyway, I was messing with it today and I found some stuff that worked and some that didn't.

I turned on my compressor, let it fill up, and turned the regulator to about 40 (prolly 40-45) psi. The guy who I bought this from had a pressure gauge right under the gun and that read about 40 psi too. When I pull the trigger the pressure drops some, is that normal?

The first paint I tried was some latex enamel interior paint. It was pretty thick. After fooling with the settings a bit, I got maximum flow and the lease splattery pattern with the air coming from the 8 holes right around the paint hole (as opposed to the 4 holes that were on the little wings. The distribution of air was adjusted by a knob on the side. What is the point of changing the airflow?
I had to hold the gun very close to the target (scrap mdf) to get any sort of coverage, less than six inches.
I tried thinning the paint out with some thinner, then realized it needed to be thinned with water, but it was dinner so I poured some water in the bucket and sprayed until it was just water. When it was jut water spraying, it actually looked like a respectable spray. I took the bucket off the top, cleaned it. Then I took the air directing nozzle assembly off, and took a wrench to the fitting that was behind that. That came off and revealed the little paint "chamber." I cleaned that out with a water hose. I also unscrewed a knob on the rear of the gun and took out the pin and spring, just to see what was up. Then I sprayed it with some air to get the water out and put it back together. Is this the right way to clean this thing? It seemed like a lot of work.

After dinner, I set up some lights and tried my luck with some white oil based paint we used on the trim in the house. It was thinner than the brown latex paint used in the paragraph above. It may have been thinned prior to me using it. I tried some of it straight from the can into the sprayer and it sprayed much better than the thicker brown paint. I also thinned it out some more with some thinner and tried again. Obviously, it was thinner so it was a finer mist. Can I use both types of paint in the gun? The latex dries faster and cleans up easier, so I prefer it. Also, how am I supposed to know when the paint is thin enough?

When I was done with that, I cleaned out the paint bucket, and sprayed until it was just air. Then I pouring in some thinner and shot that through. It came out clear. I took it all apart and, using some thinner, cleaned it. It took about 10 minutes to clean. Is ten minutes about how long it should take me to clean the thing?

And there is a knob on the bottom of the sprayer, right in front of the air hookup. Turned all the way one way, it cuts of the air, but otherwise it seemed to do nothing. Does it do anything?

I planned on using it to spray boxes and furniture, not cars, btw.

bass-aholic
05-13-2008, 11:50 PM
yes

kovemaster559
05-13-2008, 11:52 PM
normal for the psi to drop durring application.
to change the wide ness of the spray u have to use the top knobs.
we used to clean the gun with acetone it works good take the whole gun apart and spray it in a acetone washer.
i dont know what kinda paint ur using it depends automotive paint is different from latex .about ten minutes is ok just make sure the gun still feels and sprays like new if not clean it again acetone only if u want it to last!!! worked in autobody for 4 years

Harleyfx69
05-13-2008, 11:52 PM
you want even coverage on your surfaces your spraying,

Not splatters or squirts,

Thinner shoots easier ,

And your probably not even using the right gun to shoot house paint ..

Thin it down till its like a really thin syrup at minimum ,

or get something like a wagner power painter ..

Most automotive paints are more like water ,

While your heavy primers are thick like syrup, but they still spray out fairly well ..

You just need a bigger nozzle,

i have several guns i use, one of which was a cheap gun off ebay that fit the specs for shooting really thick paint, i use this for primer and it works quite well ,

The others are high end guns for paint and clear coat ..

fwb_1234
05-13-2008, 11:57 PM
Where can I get a bigger nozzle?

Oh, and I have a plug in sprayer, I'll definitely have to try that. I totally forgot about it.

Acetone sounds ok. I'll probably get whatever is cheaper, then.

kovemaster559
05-14-2008, 12:04 AM
Where can I get a bigger nozzle?

Oh, and I have a plug in sprayer, I'll definitely have to try that. I totally forgot about it.

Acetone sounds ok. I'll probably get whatever is cheaper, then.

acetone aint cheap i hate the prices of auto body .what are u spraying but yeah if its house paint et the wagner i think u can rent them at homedepot. as for painting cars and clearing ur ganna need a nice gun devil bliss something like that dont take chances when spraying expensive paint auto paint is expencive depends brand and stuff like that

fwb_1234
05-14-2008, 12:22 AM
Nope, no cars. I just got it for free and was wondering if I could use it instead of spray paint to paint boxes and such.

MikeyB
05-14-2008, 12:30 AM
Questions are bolded.

So, I got this with my compressor, used. It's a central pneumatic (read: Harbor Freight), but it seems that it would be hard to mess up that technology.

Anyway, I was messing with it today and I found some stuff that worked and some that didn't.

I turned on my compressor, let it fill up, and turned the regulator to about 40 (prolly 40-45) psi. The guy who I bought this from had a pressure gauge right under the gun and that read about 40 psi too. When I pull the trigger the pressure drops some, is that normal?

The first paint I tried was some latex enamel interior paint. It was pretty thick. After fooling with the settings a bit, I got maximum flow and the lease splattery pattern with the air coming from the 8 holes right around the paint hole (as opposed to the 4 holes that were on the little wings. The distribution of air was adjusted by a knob on the side. What is the point of changing the airflow?
I had to hold the gun very close to the target (scrap mdf) to get any sort of coverage, less than six inches.
I tried thinning the paint out with some thinner, then realized it needed to be thinned with water, but it was dinner so I poured some water in the bucket and sprayed until it was just water. When it was jut water spraying, it actually looked like a respectable spray. I took the bucket off the top, cleaned it. Then I took the air directing nozzle assembly off, and took a wrench to the fitting that was behind that. That came off and revealed the little paint "chamber." I cleaned that out with a water hose. I also unscrewed a knob on the rear of the gun and took out the pin and spring, just to see what was up. Then I sprayed it with some air to get the water out and put it back together. Is this the right way to clean this thing? It seemed like a lot of work.

After dinner, I set up some lights and tried my luck with some white oil based paint we used on the trim in the house. It was thinner than the brown latex paint used in the paragraph above. It may have been thinned prior to me using it. I tried some of it straight from the can into the sprayer and it sprayed much better than the thicker brown paint. I also thinned it out some more with some thinner and tried again. Obviously, it was thinner so it was a finer mist. Can I use both types of paint in the gun? The latex dries faster and cleans up easier, so I prefer it. Also, how am I supposed to know when the paint is thin enough?

When I was done with that, I cleaned out the paint bucket, and sprayed until it was just air. Then I pouring in some thinner and shot that through. It came out clear. I took it all apart and, using some thinner, cleaned it. It took about 10 minutes to clean. Is ten minutes about how long it should take me to clean the thing?

And there is a knob on the bottom of the sprayer, right in front of the air hookup. Turned all the way one way, it cuts of the air, but otherwise it seemed to do nothing. Does it do anything?

I planned on using it to spray boxes and furniture, not cars, btw.

Alright, dont expect too much out of the gun as its a cheapo and it will probably need more nosel pressure than its rated at to get proper atomization of paint. The knob at the back of the gun is for the fluid needle. Remove this assembly as well as the cup and the tip when cleaning. Your air pressure is adjusted at the hose and you should have a good regulator if your serious, if not a simple cheater valve will do okay for painting that doesnt need to be perfect.

For most painting with HVLP guns you use a variety of tips depending on the material your spraying. Most high-build primer surfacers are sprayed with ~1.5mm tip, Sealer with a 1.3~1.4mm and Top Coat and Clear Coat with ~1.3mm, some people have their preferences but this is usually how its taught.

When spraying you want to spray all jams first leaving the outer beauty areas that are seen the most to be sprayed last with even strokes with 50% overlap. The gun should be about the width of your fist away when spraying ~6-10 inches depending on what your spraying.

These are the best tips I got for you without diving into it too much.

Hope that helps, let me know if you need help with anything else or have any questions.

fwb_1234
05-14-2008, 12:47 AM
http://www.stovebolt.com/techtips/images/hvlp_spraygun.gif

This is almost exactly what mine looks like. Also, what is the hook type thing on top for, right behind the cup?

Harleyfx69
05-14-2008, 01:15 AM
that would be a hanging hook ..

BrianChia
05-14-2008, 01:22 AM
that would be a hanging hook ..

:laugh:

fwb_1234
05-14-2008, 01:46 AM
Just wondering. I thought it might have some other function because it wiggled.

basshedz06
05-14-2008, 07:09 AM
for one want your paint down to like the consistency of milk that is how i use my paasche airbrush nothinglike this one u have i am looking to get on like this one in the near future for painting model cars. yes keeping your guy clean is a must u have to keep it clean if uwant it to work properly and last long. no matter if its cheap or very expensive a guns life depends on how u take care of it.
i use mostly waterbased paints to do my models in so water is my thinner and its pretty much ready to spray when i buy it at the stores.