paint spray gun not spraying enough paint; causes?

[BTL-A4]

I have a cheaper Harbor Freight spray gun I bought a few years ago to paint a car with single-stage automotive paint. It worked well and I had no issues. It is always cleaned thoroughly. I've since used it to paint a pergola with water-based Home Depot paint and that went well. I just used it again to paint a small shelf with the same HD paint and the paint was hardly coming out at all.

The tip is 1.4mm, I had the knobs all set for maximum paint and air, and I varied the pressure (I think it was about 12-25 at the inlet on the gun) to get whatever worked. It turned out that the higher pressures seemed to get the most paint out, but not by much. I also played with the other knobs and it didn't make much of a difference as to how much paint came out.

The paint came out intermittently and not in large amounts. I thinned it with water, per the instructions, about 1:8, but it might have been too thick. It had the consistency of thick water, or normal paint. I poured it through a mesh filter into the paint cup on the gun. It took forever; I think the mesh may have been too fine.

Any insight as to why this spray gun would not spray a decent quantity of paint? Is it worn out? Was the paint too thick?

 

[Ohmthis]

Did you remove the little white filter at the bottom where the paint cup screws in? Those are terrible for clogging. I’d tear the gun completely down and using lacquer thinner and a soft brush, clean it thoroughly. The fluid adjustment might be out of adjustment. Watch this and clean it good, let us know how it goes. this is not my video, nor do I even know who the person is. There are dozens of videos on the purple gun.

 

[BTL-A4]

Thanks! That little filter was probably this issue! It occurred to me as I was putting the sprayer back together that that could be blocking the paint, as it has a very fine mesh on it. The video above mentioned removing it if you are spraying anything with heavy flakes in it, so I'm guessing that also applies to heavier-bodied paint.

 

[The Cobbler]

I was having an issue with a spray gun that I use for solvent based paints only, I discovered that my not so clean gun wasn't as clean as I thought it was. there was a large buildup of paint up inside that I had to clear out .
and yeah, those filters are very fine, that is a very good possibility.

 

[Mandres]

If you haven't, make sure to remove the fluid needle and the fluid tip and clean them out too. I throw those little filters straight in the trash, just a problem waiting to happen.

 

[Ohmthis]

Thanks! That little filter was probably this issue! It occurred to me as I was putting the sprayer back together that that could be blocking the paint, as it has a very fine mesh on it. The video above mentioned removing it if you are spraying anything with heavy flakes in it, so I'm guessing that also applies to heavier-bodied paint.

Remove those filters for any kind of paint. You should be filtering your paint with a filtered funnel. Sorry if you don’t use Amazon. It’s usually the fastest way to find things I want to show.

Amazon.com

 

[Spareparts]

Those little filters are a PIA, was spraying some implement paint, thought I needed them,went to Car-Quest to get some, $50
for a pack of 5,seems I didn't need them anyway, it sprayed just fine

 

[OccupantRJ]

Those little filters are a PIA, was spraying some implement paint, thought I needed them,went to Car-Quest to get some, $50
for a pack of 5,seems I didn't need them anyway, it sprayed just fine

For that price you can buy 5 more of the guns when on sale.

 

[BTL-A4]

I took the filter under the paint cup off. It worked a little bit better, but not much. I had to wipe the paint off the tip every once in awhile or it would clog. It was a hot day (100º), so the paint gto a little gummy, even when I adjusted the pressure. I may not have thinned the paint enough, or maybe thinned it too much, hard to tell, as I just guessed what 1:16 looked like. It was Behr latex satin. Directions say to thin it no more than 1/2 pint per gallon, and use a 0.015-0.019" spray tip. I was using a 1.4mm, which is 0.055".

 

[The Cobbler]

Directions say to thin it no more than 1/2 pint per gallon, and use a 0.015-0.019" spray tip

those specs are probably for airless spraying .
1.4mm is a tad small for latex paint to atomize in an air spray gun I think.
There are videos on you tube where people drill the tip out a bit to enlarge it for spraying latex.
I have a gun that I used for latex on a job and if I recall it was over 2 mm .

 

[e015475]

I've been using those HF guns for years with good results for mostly automotive stuff. For individual parts and trim, they work well. If there's something larger, the Iwata comes out.

I needed to spray some latex to finish some cabinets, so I found a youtube video on how to drill out the nozzle on the HF gun - what a disaster and the gun ended up in the trash/parts bin.

What really worked excellent was a gun called a 'HomeRight' that I bought on Amazon. The cabinets I sprayed with it looked like a pro painter did them. About $60 on Amazon.

Recently I needed to spray some Featherfill (basically liquid body-filler for automotive panels) and it is pretty thick. The purple HF gun will work, but it is pretty tedious because the volume is so low. For $10 I bought a non-HVLP gun at HF that pressurizes the paint pot and that really puts out the flow of thick material. (I didn't want to try the plastic HomeRight gun for this out of fear the reducer would melt it)

 

[niget2002]

Was this an older can of paint? If so, how did you mix it back up? If the paint is old, it could be that the solvents in it evaporated out and it's thicker than it should be.

I've mostly had good luck spraying latex with Floetrol mixed in.