Why does this keep happening. I have a Paasche VL airbrush and every time I use it the mix will come out very watery and it wont stick. The paint runs down the side of the model and I am NOT [banghead]happy. Why is this happening? The paint wont fade a model, it will put white streaks all over. Is it the PSI maybe???[:S] Help Please!
It sounds like your paint mix is way too thin. What paint are you using and how are you thinning it?
Hey UPTeen23,
Although I shoot Lacquers, the previous post & your thoughts sound correct. Too thin a-mix will blow & run, a too close a hold will do the same, -& for me that was the hardest thing to master & overcome, holding a consistant distance from the model! Take a scrap & try painting at different distances, if they are all too wet it is your thinning. ( I’ve talked to you before & know you how to clean & prep your shells before painting, so I will not go there, cuz you already did that.) Over pressure can also drive harsh runs, especially so with a close proximity of the brush. Seriously, I still find myself shooting ‘too close’ a lot, especially with weathering colors that don’t immediately cover, It’s something I have to, & do, work on quite a bit. Let me know your results.
Later,
UP,
Above posts are on the mark. It would help if you told us which paint products you’re using, how you’re mixing them, your air pressure settings, and your aircap-nozzle-needle setup.
I suspect that you might be shooting with acrylics but don’t want to jump to conclusions yet. Post back.
I am using Polly Scale paints and also regular Flouquil enamel paints. BTW the main use of the airbrush is weathering and painting track so it could be PSI problems. I dont have a regulator on the Paasche compressor so maybe it is too high. Also I am thinning the paint typically 3 or 4 part water or alcohol to 1 part paint.
I’ve never done weathering, but I’ve done plenty of airbrushing. When doing a full color, I usually mix about 2 parts paint to 1 part thinner, and even that’s pretty thin. Almost like whole milk.
With the mix you have, you’re pretty much just spraying water. Water doesn’t stick. I would suggest decreasing the amount of thinner to about a 50/50 mix to start with, and then practice on something. Maybe widen the spray output if you can, do quicker strokes, and hold it farther away. Like I said, I’ve never done weathering, but I do know that quick, wide strokes will give a thin and practically transparent layer of paint. Just keep going until you find the mix and method that works best.
UPTeen23,
You are thinning way too much! Here is a good set of values:
Badger Acrylic - Air Brush Ready(no thinning needed).
Floquil Poly Scale(acrylic) - Thin it to the consistancy of 2% milk
Floquil(lacquer based) - Thin it to the same consistancy.
Floquil paints are not air brush ready, and vary with the amount of thinner needed. For doing weathering, you should thin it a ‘little’ more that I posted above, but no very much. The air pressure is critical. You need some way to measure the pressure. I usually use 15 psi for weathering with my Badger ‘internal mix’ air brush. I use about 20-25 lbs for painting a model with acrylic paints. Most external mix air brushes produce too much ‘splatter’ on the model. Your double action, internal mix VL should do a wonderful job of painting your models. Get a combination regulator/moisture trap and place it between your compressor and the air brush.
Jim
I have a friend who sprays only acrylics, and he uses blue winshield washer fluid (alcohol based) to thin his paints. He says water is no good for thinning. (I use solvent paints, so I do ont have any direct experience)
As far as weathering, you do not have to over-thin the paint. I dial down the airbrush until almost no paint is spraying. I spray onto a white paper towel to adjust the paint stream until it is right, then spray the thin stream onto the model until the weathering looks right.
UPTeen23,
It also sounds like you don’t have your air paint mix valve set correctly. Take a piece of cardboard and place it against the wall or whatever and just use plain solvent in the jar. then turn the valve closed until nothing but air comes out of the nozzle . then slowly open the valve until the solvent comes out to the desired flow is achieved. Takes practice but saves on paint.
Frank
OK
You definitely need a regulator to obtain quality jobs. Without one, it’s often going to be “hit or miss” on paint and weathering jobs. You don’t have to spend $40 on the high end units. You can purchase affordable regulators from Harbor Freight, in person or online:
https://shop.harborfreight.com/catalogsearch/result?q=air+regulator
For weathering 1 part paint to 1 part distilled water works well for me and only go 1part paint to 2 parts distilled water for weathering washes (where I want tiny nooks and crannies to stand out. Needle-Aircap-Nozzle setup: #3. Air pressure: 20-25psi.
Again, the regulator will help make a difference. You’ll likely need a 1/4" outside threaded nipple (brass instead of steel).
What type and brand compressor are you using?
I agree with Jim on the regulator. Not only can you easily adjust the pressure, the moisture trap is essential for a good paint job.
You did not mention where you live, but, even at 15 or 20 psi, the compressor will raise the relative humidity of the air to above the dew point. You will then get moisture drops in the paint stream which can leave spots on the painted surface. I live in Maine, and in the winter in my dry basement, I do not see much moisture in the trap. In the past few weeks, however, with warmer temps and spring rains outside, I am starting to see moisture in the trap after only a few minutes of painting.
I open the valve and blow down the trap after every paint session to get rid of the collected moisture.
The compressor is a Paasche D500. BTW thank you all for your help!
While I totally agree with the need for a regulator and a moisture trap, both Floquil and PollyScale can be thinned at least 90% (nine parts thinner to one part paint) for weathering. I also use a Paasche VL, usually spraying at 20-25psi for Floquil and 15-20 for PollyScale. I use lacquer thinner to thin Floquil and distilled water for the PollyScale. Set the needle so that no paint will spray when the trigger is depressed only, with paint flow occurring only when the trigger is both depressed and pulled back. I use the #1 tip for all painting.
If you’re having difficulty maintaining an even flow, practise on a piece of cardboard until you get the effect you’re after, then set the paint flow adjusting knob to give that same paint flow when the trigger is depressed only, and not pulled back.
Your VL came with a booklet of practice exercises: I suggest that you, after installing a regulator and moisture trap, get some cardboard cartons from the supermarket, break them down and try the exercises. Once you have mastered control of the airbrush, painting and weathering will become a much more enjoyable experience.
Wayne
I agree with Jim and Wayne, especially about practising first! Use the exercersises provided in the Paasche booklet, they will quickly get you familiar with brush. It also sounds like you’re pulling the trigger all the way back. Do as Wayne said and start with just air and slowly pull the trigger back untill paint just starts to flow. Since you don’t have a regulator, the trigger is the only way you have to adjust paint flow.
To practice painting (not weathering) thin the paint according to Jim’s recommendations, a consistency of 2% milk is what you want, whatever the ratio of paint to thinner/water. A little trick I recommend for beginners is to pour a little 2% milk in a glass, swirl it around and watch how it falls down the sides of the glass, you want the paint to act the same way. The airbrush should be about 4 to 6 inches from the model or practice cardboard. Start as Wayne suggested, with just the air , then slowly pull back on the trigger to let the paint flow, now move your arm from left to right at a medium speed while keeping your hand parrallel to the surface you’re painting. The paint should look slightly wet as it lands. Do not try to get full coverage in one pass. With an air brush one should get full coverage in 2-4 light passes. Practice this and the excersises for about 1/2 hour and you should have the hang of it. From there you can play around with your thinner/paint ratios for weathering. Practice some more on some cheap freight cars.
I do recommend you get a regulator and moisture trap as the Paasche compressor puts out about 30-35 PSI which is about 10-15 PSI too much, especially for weathering, most of which should be done at about 15-20 PSI.
With acrylics I highly recommend screening the paint, I use my mother’s and girlfriend’s nylon stockings/pantyhose thro-aways. Be sure to thoroughly stir the paint, don’t just shake the bottle. Coffee stirrers wor
With Acrylics I only use rubbing alcohol as a thinner. I mix 50/50. The dry time is only a few minutes and rarely runs. Also make sure you properly stir/shake the paint before using.