bobthehobbyguy Posted November 11, 2014 Share Posted November 11, 2014 Another thought. Are you sure you have the right tip , cone, and needle together. Quote Link to comment Share on other sites More sharing options...
YoungLuis Posted November 11, 2014 Author Share Posted November 11, 2014 I'm using a Paasche VL so double, regatding the paint I'm using that cheap apple barrel acrylic until I get the hang of the airbrush, and I'm mixing it 70% water 30% paint, and I'm sure I have the needles and heads correct but I'm guessing on which tip goes with what combination Quote Link to comment Share on other sites More sharing options...
bobthehobbyguy Posted November 11, 2014 Share Posted November 11, 2014 Might try say an 60 40 mix. Quote Link to comment Share on other sites More sharing options...
Ace-Garageguy Posted November 11, 2014 Share Posted November 11, 2014 (edited) So this is something I have wondered about since I bought my airbrush: what is the actual air pressure in the circuit both when the airbrush is idle and when it is wide open. normally I set my regulator at 25 psi because that is what I am told is appropriate. I then point and open my airbrush and immediately the pressure drops to 12 psi or so. there are no leaks or anything other than the obvious leak in the airbrush. the question is, which reading is accurate, and further, which reading is what one should pay attention to when receiving advice on the optimum pressure to shoot paint. I had figured it was the pressure with the system closed (airbrush idle). I guess it makes more sense to use the pressure when it is being used and the circuit is open. the thing there is that means to run the pressure up around 40 or more psi at idle so it will drop to the correct range when the airbrush is opened. and it also means that when I get advice about optimum pressure I have to wonder where exactly they are measuring the pressure. Frankly, I don't think the majority of modelers have really thought that particular question through, and that could be one reason I see so many wildly varying recommendations on what pressure to use. In the REAL CAR world, the pressure you shoot paint at is the pressure at the gun with the trigger pulled to wide open. Static line pressure with the trigger closed and no air flow means absolutely NOTHING, and can range as high as 120-130psi. Typical pressure measured at the gun (any decent painter will have an air pressure readout and regulator of some kind at the gun...some now are even digital) is in the range of 40psi for an old siphon-style rig, down to 15psi or lower for a gravity-feed HVLP unit. I'm certain that pressure recommendations for air-brushing, to have any validity at all, need to focus on the regulated pressure at the AB with the trigger wide open. --------------------------------------------------------------------------------- Viscosity is pretty well standardized by most real-car paint manufacturers these days, as specific mixing ratios are duplicated reliably by use of graduated mixing-sticks or cups, but minor tweeking of viscosity is still often necessary and only experience gets you the requisite "feel". Where absolute repeatability is necessary, a "viscosity cup" (a device of a specific volume, with a calibrated hole is dipped in the paint mixture, and the runout-time through the hole is measured in seconds; then thinner is added until the time equals the predetermined spec). http://en.wikipedia.org/wiki/Zahn_cup Real-car viscosity cups are way too big to use for model work, but you can make your own small one fairly easily. I personally use the "count the drops" method...stick your mixing stick in the paint and see how fast, say, 5 drops fall off of it as you pull it out. A little practice will have you getting closely repeatable viscosities. If you REALLY want repeatable, consistent, quality results, keeping records of your mixing ratios for specific paints, and air pressures and needle adjustments that provide the effect you want, can help immensely. Edited November 11, 2014 by Ace-Garageguy Quote Link to comment Share on other sites More sharing options...
Erik Smith Posted November 11, 2014 Share Posted November 11, 2014 Great advice ^ Working pressure is what matters. Also, you can regulate pressure with the set up pictured - it has a bleed valve airflow adjustment below the water trap - similar to my Iwata compressor. Quote Link to comment Share on other sites More sharing options...
YoungLuis Posted November 12, 2014 Author Share Posted November 12, 2014 (edited) The more I use the airbrush, mix paints, and spray numerous amounts of test bottle of cheap paint, I realize how important paint consistency is! To me probably more important than psi, since at the same psi I was able to shoot acrylics, cheap acrylics that are about as thick as they get, and enamel! But I was glad to see that I was able to shoot a bottle of testors Acrylic Flat Black straight from the bottle! These are the results! Now I can continue with the '68 charger! Thanks to all of you who helped! Edited November 12, 2014 by YoungLuis Quote Link to comment Share on other sites More sharing options...
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