Airless paint sprayer help: primer OK, but enamel has streaks/tails


I have a Graco Magnum DX sprayer with the 515 tip (0.015"). I also added another 25' 1/4" hose section at the sprayer and coupled that to the 3/16" 25' hose that came with the sprayer. I am painting my trim and doors in my basement. The sprayer worked well for the latex primer (Sherwin Williams PrepRite Classic). I set the sprayer to about half pressure (middle of full and prime/clean).
I then flushed the sprayer with water and then paint thinner and switched to the enamel (Sherwin Williams ProClassic Interior Alkyd Satin Enamel). At half pressure there was considerable streaking/tails in the paint pattern (4 or 5 main streams of paint). At full pressure the streaking/tails were better but still not very good. I then tried a 411 tip (0.011") but the spray with that was worse than the 515 tip.
The enamel is considerably thinner than the latex so I thought the smaller tip was going to help but it did not. I have cleaned the gun filter and flushed the sprayer again.
Should I try using just the one 25' 1/4" hose or maybe just the 25' 3/16" hose? Should I try a 0.017" tip even though the max tip for the DX is 0.015"? Or is this sprayer just not going to work for the enamel?
Thank you!!
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snipped-for-privacy@gmail.com wrote: At half pressure there was considerable streaking/tails

The proble may not be with your sprayer but with your technique. Not sure exactly what you mean by streaking and tails however. I have an Graco airless and have used it long enough to learn a few tricks don't know it they will help you.
It sounds like you are applying too much paint too slowly. The idea is to apply very thin coats very quickly is what you should shoot for. A thin coat will dry quickly and keep you out of trouble with over applying. Massive overapplication is easy to do with an airless and can be your worst nightmare.
You want to be sure the nozzle is perpidicular to the direction you are fanning the gun, up and down. You can get streaking when you are applying too much paint too slowly. To fix it you want to a lower pressure not higher. I like to use the lowest pressure my situation will allow.
fan the gun back and forth across the surface very, very quickly. Paint the surface in overlapping passes. This will apply the paint more evenly. Do not trigger the gun continuously. Trigger the gun just before entering your pass and release the trigger just before the end of the pass. You will therefore trigger the gun with every pass. Keep the gun parallel to the surface rather than swinging it in an arc. Also keep your gun at a consistent distance about 12 inches or a bit more. Move back an inch or two if you see streaking.
Another fix is to use an roller. It is something of a defeat, I know, to use a roller when you have commited to the sprayer but it's really no big deal. Do a wall and if it has streaks you should be able to even out quickly with the roller while the paint is wet. Stop after each wall to check for streaks and try to improve your technique each time.
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Thanks for the response Lawrence!
I think my technique is ok. The problem is that I am not getting an even/uniform spray. When I spray I get 4/5 pronounced streams with a significant gap between two of them. Its not terrible but its not good enough to paint my interior doors. It might be good enough to paint my door frames and windows though.
Lawrence wrote:

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snipped-for-privacy@gmail.com wrote:

Did you strain the paint before pumping? Could perhaps have a clog? Do you have a viscosity cup to check the paint viscosity and thin as appropriate?
Pete C.
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I did not strain the paint but I don't think I have a clog but I guess its possible. I just talked to a painter and he said there are different kinds of tips. The black ones (what I have) are mainly for latex and the green ones are for finer stuff like oil base so I'm going to try a green tip.
Pete C. wrote:

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snipped-for-privacy@gmail.com wrote:

I think you are using the right tips. I looked at my machine ( Graco Nova 395) and I am using a 413 tip and also have a 517 on hand using oil based primers and enamels.
You many have the tip in backward. the graco has self cleaning tips. when they get clogged you just turn them around and run the sprayer to unclog. There is an arrow on the tip which shows the direction the paint flows when the gun is in use. I have made the same mistake.
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I bought a Graco FF 312 tip (green) yesterday and it works much better. I still have to have the pressure maxed out but I am getting a good spray pattern now.
Lawrence wrote:

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On 3 Jan 2007 06:17:55 -0800, snipped-for-privacy@gmail.com wrote:

Try adding some Penetrol to oil base and Flotrol to latex. See package directions.
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