dai phan Posted July 16, 2022 Share Posted July 16, 2022 (edited) Hi all, What causes the airbrush to spit out tiny pin head droplets that ruined my paint job? I sharpened the needle, install new water trap, thin the paint, mix 3 times longer on my shaker but still ... Please help. Dai Edited July 16, 2022 by dai phan Quote Link to post Share on other sites
Bob Beary Posted July 16, 2022 Share Posted July 16, 2022 You said you sharpened the needle. How did you do that? That seems to be the only thing that has changed in the equation. I would first try a new needle and see if that makes any difference. HTH Bob Quote Link to post Share on other sites
dai phan Posted July 16, 2022 Author Share Posted July 16, 2022 1 hour ago, Bob Beary said: You said you sharpened the needle. How did you do that? That seems to be the only thing that has changed in the equation. I would first try a new needle and see if that makes any difference. HTH Bob I use sand paper to make the point really sharp. Still no go. Dai Quote Link to post Share on other sites
Chuck1945 Posted July 16, 2022 Share Posted July 16, 2022 1 hour ago, dai phan said: I use sand paper to make the point really sharp. Still no go. Dai Why? There should be no need to sharpen the needle and unless you used something akin to polishing grade grit, the sanding could actually damage the needle and disrupt the air/paint mix and flow. Smoothness, not sharpness is what matters. Quote Link to post Share on other sites
Bob Beary Posted July 16, 2022 Share Posted July 16, 2022 That's what I was thinking as well, hence my suggestion to try a new needle. Dai...are the droplets pure paint or paint/water? Is your compressor tank (if it has one) been bled recently? I know you put a new water trap on...is there any water in it? Paint should be stirred, not shaken. And was the paint properly thinned? Bob Quote Link to post Share on other sites
Rob de Bie Posted July 16, 2022 Share Posted July 16, 2022 7 hours ago, dai phan said: What causes the airbrush to spit out tiny pin head droplets that ruined my paint job? I sharpened the needle, install new water trap, thin the paint, mix 3 times longer on my shaker but still ... Please help. Dai If this spitting only happens after a while, and not straight from the start, then the design of the spatter cap could be the problem. Paint slowly collects in the corners of the spatter cap because of the vortex inside the cap, and once enough has built up, a droplet is spit out. I made a crude drawing of the vortex that creates this problem: Here's how I modified my Badger 150, with the two designs of the Badger cap in the background. It definitely solved the problem, but now the needle is constantly exposed. Rob Quote Link to post Share on other sites
dai phan Posted July 17, 2022 Author Share Posted July 17, 2022 (edited) 4 hours ago, Bob Beary said: That's what I was thinking as well, hence my suggestion to try a new needle. Dai...are the droplets pure paint or paint/water? Is your compressor tank (if it has one) been bled recently? I know you put a new water trap on...is there any water in it? Paint should be stirred, not shaken. And was the paint properly thinned? Bob Bob, The droplets are paint, not water as I have moisture trap. I mix the paint really well but still. I also make sure the paint is thinned properly. I use Mr Color and I only experience the problem as of late. Dai Edited July 17, 2022 by dai phan Quote Link to post Share on other sites
dai phan Posted July 17, 2022 Author Share Posted July 17, 2022 2 hours ago, Rob de Bie said: If this spitting only happens after a while, and not straight from the start, then the design of the spatter cap could be the problem. Paint slowly collects in the corners of the spatter cap because of the vortex inside the cap, and once enough has built up, a droplet is spit out. I made a crude drawing of the vortex that creates this problem: Here's how I modified my Badger 150, with the two designs of the Badger cap in the background. It definitely solved the problem, but now the needle is constantly exposed. Rob I have used the Iwata HP- B Plus and before no problem. I clean my AB really really well after each session. Dai Quote Link to post Share on other sites
Chuck1945 Posted July 17, 2022 Share Posted July 17, 2022 The question remains, why are you sharpening your airbrush needle? If the problem began occurring after you sharpened it, that is a good clue that perhaps sharpening isn’t a good idea. If you have an unsharpened needle, try using it and see if the problem persists. Compared with perhaps the needles in H&S airbrushes, the Iwata needle is not as pointy sharp but people use the Iwata without problems and without sharpening the needle Quote Link to post Share on other sites
bobjohnston Posted July 17, 2022 Share Posted July 17, 2022 Hi, if you are going to try and sharpen a airbrush needle then you need to use this device as it makes it easy. https://sharpenair.com/ cheers. Quote Link to post Share on other sites
dai phan Posted July 17, 2022 Author Share Posted July 17, 2022 32 minutes ago, Chuck1945 said: The question remains, why are you sharpening your airbrush needle? If the problem began occurring after you sharpened it, that is a good clue that perhaps sharpening isn’t a good idea. If you have an unsharpened needle, try using it and see if the problem persists. Compared with perhaps the needles in H&S airbrushes, the Iwata needle is not as pointy sharp but people use the Iwata without problems and without sharpening the needle In my naieve mind I thought needle needs to be sharpened every few years. But that should not cause the tiny paint droplets to form right? Dai Quote Link to post Share on other sites
habu2 Posted July 17, 2022 Share Posted July 17, 2022 In my work I do a lot of troubleshooting. When something suddenly changes for no apparent reason I ask myself "what did you last touch?". Your description states the only variable is sharpening the needle. Get a new needle (in fact get 2 for a spare) and see if that rectifies the problem. If not then you have at least eliminated the needle as a problem. Quote Link to post Share on other sites
ElectroSoldier Posted July 18, 2022 Share Posted July 18, 2022 Dont change the needle by sanding it. Change the needle and the nozzle and the problem will stop. Quote Link to post Share on other sites
James B Posted July 18, 2022 Share Posted July 18, 2022 Never let off the air while you are airbrushing. Stopping the air allows paint to dry on the needle. This dried paint disturbs the airflow and causes droplets to form. You can stop the paint flow, but never stop the air flow. I also keep a cotton swab that I have pulled the cotton a little lose on the tip, soaked in thinner, at my spray booth. I stay in the habit of cleaning the tip ever 30 seconds or so. Quote Link to post Share on other sites
dai phan Posted July 18, 2022 Author Share Posted July 18, 2022 (edited) 34 minutes ago, James B said: Never let off the air while you are airbrushing. Stopping the air allows paint to dry on the needle. This dried paint disturbs the airflow and causes droplets to form. You can stop the paint flow, but never stop the air flow. I also keep a cotton swab that I have pulled the cotton a little lose on the tip, soaked in thinner, at my spray booth. I stay in the habit of cleaning the tip ever 30 seconds or so. I do use the cotton swab in thinner and clean the nozle after a minute of spraying. And I start the paint flow away from the model. There were so many droplets that I now have to strip and start over. Dai PS: Just ordered two needles. Edited July 18, 2022 by dai phan Quote Link to post Share on other sites
BrailleScaleModelMaster Posted September 3, 2022 Share Posted September 3, 2022 I would not have messed with the needle. They are ground to dimensions designed to fit well into the nozzle. Quote Link to post Share on other sites
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