why does paint shot through airbrush feel like sandpaper?

[The Creative Explorer]

I am seriously getting pissed and thinking of tossing everything outside, close down the hobby.

I've been using Zero Paints now for a while, but since a while (don't exactly since when, but long time) whenever I use the airbrush to paint, the paint ends up feeling like sandpaper, very course. Whereas Zero should feel as smooth as the surface.

In a way, I also have that problem with acrylics, but not that problematic (I have other problems with acrylics, why I don't use them that much no more).

It doesn't matter if I shoot it with high or low pressure, much or little paint or thick or thin coat of poaint. I am clueless and the fun of modelling went down the drain quite quickly.

Anybody a clue of what I can do?

[Longbox55]

There may also be the possability that you may be too far away from the surface when you are painting, causing the paint to partially dry before it hits the surface.

[JunkPile]

Practice, practice, practice

[The Creative Explorer]

@Steve: Zero paints is specifically for the airbrush and thin enough, so that's not the problem.

@Bill: I am about 2-3 inches away from my object, it should be a normal distance to shoot. When shooting from a too far distance, one get a sand-cast appearance, this is different. Happens mostly at curves, especially negative curves, and around windows.

@Chuck: I'm sorry, but please don't post if you don't have anything to post. This has nothing to do with practice.

[JunkPile]

Well then you will have to explore your creative side until you figure out how to use an airbrush, related materials and techniques required. Or you could just quit.

Edited July 22, 2012 by JunkPile

[The Creative Explorer]

Chuck: appearantly you have some difficulty to read? Again: If you don't have something to say, don't say anything at all. You don't add anything, just trolling. Do me a favour and refrain from posting. You really live up to your nick.

Edited July 22, 2012 by The Creative Explorer

[The Creative Explorer]

I did another attempt, but same results.

Used the 0,4 needle. 24-25 psi pressure (that's all my compressor can do while pumping and have no tank (yet)) and had the hood about 4-5 inches from the airbrush.

Conclusion: I can make 240grit sandpaper! I just don't understand why.

When I use Vallejo paints, same setting. No problems at all.

[Ace-Garageguy]

When I use Vallejo paints, same setting. No problems at all.

So, the rational, reasoned answer would be that there is some specific difference between the paint that works, and the paint that doesn't, right? Even though "Zero paints is specifically for the airbrush and thin enough, so that's not the problem" as you say, the viscosity of the paint may be simply too high to work correctly in your particular airbrush.They are NOT all exactly the same. If you haven't tried thinning it further, then I suggest you try that. Also make certain that the vent for the paint container isn't clogged.

Are you using a gravity or siphon feed airbrush?

Though Chuck's answer may seem a little harsh, there's truth in it, as it's your problem, with your materials and setup, and only you, with experimentation and practice can solve it. I have found that many hobby materials didn't perform to my satisfaction immediately, and it was my own error or lack or experience with the PARTICULAR material that was the actual problem.

I wish you luck as to finding the cause, and bringing the enjoyment back.

[The Creative Explorer]

I use a H&S Evolution, which is gravity feed and open air and the Zero paints are even thinner than Vallejo and it used to work fine.

Even though Chuck could have a point, just posting practice, practice, practice is neither troubleshooting nor explanatory. Therefore there is no value in his posts whatsoever.

Especially considering the fact that I am holding a airbrush for more than 5 years and do put out good paintjobs. If he had read the first post well enough, he could've read that the problem 'suddenly' started and things were good before. So it has nothing to do with practice.

And don't get me wrong, I am by far not a ace-painter, nor a pro. But I do know what to do with an airbrush. And I agree on your statement, I do have pretty good tools and most of the time I am the weakest link when applying them.

Appearantly the problem is in a faulty aircompressor, whilst it can build up enough pressure when in idle, it can't give enough pressure while being used. So, the pressure drops from a required 2,5 bar to not even 1,5.

I guess I need to hunt for either a new compressor or a tank.

Thanks for brainstorming with me William, it is appreciated.

[Art Anderson]

I use a H&S Evolution, which is gravity feed and open air and the Zero paints are even thinner than Vallejo and it used to work fine.

Even though Chuck could have a point, just posting practice, practice, practice is neither troubleshooting nor explanatory. Therefore there is no value in his posts whatsoever.

Especially considering the fact that I am holding a airbrush for more than 5 years and do put out good paintjobs. If he had read the first post well enough, he could've read that the problem 'suddenly' started and things were good before. So it has nothing to do with practice.

And don't get me wrong, I am by far not a ace-painter, nor a pro. But I do know what to do with an airbrush. And I agree on your statement, I do have pretty good tools and most of the time I am the weakest link when applying them.

Appearantly the problem is in a faulty aircompressor, whilst it can build up enough pressure when in idle, it can't give enough pressure while being used. So, the pressure drops from a required 2,5 bar to not even 1,5.

I guess I need to hunt for either a new compressor or a tank.

Thanks for brainstorming with me William, it is appreciated.

A thought here: You've mentioned the rough surface seems to happen in areas with negative shapes (I take that to mean concave, or recessed areas, such as one might find on the rear quarters of say, a '59 or '60 Chevy) and around window frames.

It sounds to me as if you might want to experiment (on something that doesn't matter if you mess it up) with lower air pressures, especially with either acrylics or lacquers, as both of those paints, when kicked up into really noticeable overspray, can dry partially in mid air, before they get deposited on the model car surfaces. I had to learn about this when starting to use automotive lacquers on model car bodies with my airbrush. Here is what I found upon careful study:

Airbrushes, with high air pressures (and 25psi is pretty high, believe it or not!) put out paint with enough velocity to create a pretty noticeable cloud of overspray, much of which dries in mid air, and at the end of the side of a model car body (or even around the raised detailing around side windows) actually "eddies" in a bit of a swirling cloud, which can settle on the surfaces of say, the rear of the body shell, in much the same fashion as dust collects on the rear of your own car or SUV when you drive down a dusty country road (surely you have experienced that, or have seen cars that have that effect on them!). So two steps here:

First, I would not assume that any brand or make of paint sold as "air brush ready" is in fact truly thinned enough. What works for one person may well NOT work for someone else, but the technique I will suggest does work, I've taught several modelers to do this: For airbrushing, lacquers should be as thin at least, as 2% milk. This is an "eyeball" thing--think of how 2% milk flows off the inside of your glass, it "sheets" on the glass,but very thinly, very translucent. This viscosity works very well with lacquers (waterborne acrylics behave much differently of course). Even with decanted rattle can paints, they may well be a bit too thick for getting a nice airbrushed finish--I find myself often adding a bit of lacquer thinner (again by eyeball!) to get that "2% milk consistency. Think THIN here.

Second, work with only the minimum air pressure needed to get the paint to flow through your airbrush. Most all airbrushes are made for the art trade, and none of the airbrush manufacturers ever really seem to take into account model car builders. So, think of your airbrush as a miniature spray gun, which in fact it is, out of which you want a miniature paint job. I always start by cutting down the air pressure delivered at my airbrush, to the point that it won't spray even the thinnest of paints. I then hold the trigger down, and open up the material control (which admits paint into the air stream) a little bit, then slowly increase the air pressure until the airbrush just begins to spray. Once I have that airpressure adjustment (and this is best done by eyeball, not necessarily by looking at a pressure gauge) I simply open up the airbrush itself to get a usable spray pattern (about 1/2 inch an inch out in front of the airbrush itself). Now I have a workable spray pattern at that distance, which is far closer than most everyone reads in the instructions as being the proper distance for spraying. Again, miniaturizing the use of the airbrush (think about how far away a production spray gun gets held from the surface of a real car at your local body shop--it's actually pretty far away,but in miniature, learn to work much closer in than you have been. Now by moving your airbrush along the sides of your model body shell, you won't be seeing nearly as much overspray in the air around your work, and very little of it will settle around the corners either on the front or rear of your body shell. With concave areas, spray those first, then work outward from them, that will give you the coverage and smooth surface you want there. Think SOFT and CLOSE here.

That's my motto in painting a model car body: TSC, or Thin, Soft and Close.

I'd suggest working with either a junk model body or two, or lacking those, get a package of plastic picnic spoons, and practice the above on those. I think you will see a considerable difference in your outcome.

Art Anderson

[Ace-Garageguy]

That sounds like some great advice Art, obviously the product of much experience and experimentation. I'm not always happy with my own airbrush results and resort to rattle-cans much of the time, which I've pretty well mastered. I'm going to try your approach and really pay attention to the results. Thanks.

[Mr. Can Am Garage]

To illustrate Art's point, this was painted using his TSC method.

DupliColor Hot Rod Primer covered with Scale Finishes Synergy Green which was cleared with Testors One Coat Wet Look Clear (all lacquers). It was then dehydrated and then glazed with Meguiars Professional Glaze and then waxed with Meguiars Hi-Tech Yellow Wax (both tan bottles).

[peekay]

Good information above. I've been using Zero base coats for a while and I also have a suggestion.

Zero suggests 2-3 coats, 5 minutes apart but I also got a rough texture doing it that way. I thin the paint at least 20% at the outset (I use their Basecoat Thinner) and apply it in many VERY light coats. Resist the temptation to go over an area again for better coverage! Wait 2-3 hours, add another coat and so on until you have even coverage. At this point I check the surface and if it's not completely smooth I sand very carefully with a Micro Mesh 4000 cloth, wash the model and dry it thoroughly with the airbrush. I then thin the paint even more and add another one or two coats.

I might typically take two days to get the colour coat on with this method but it will be a lot smoother.

[peekay]

BTW I'm assuming you realise that the base coat then needs a clear gloss coat.

[Deathgoblin]

Question: could there have been a formula change with the Zero paints? You said it happened suddenly and it sounded like you had worked with this medium before. They could have changed the paint formulation or thinning ratio and it might have thrown off your work. Just a thought.

[my80malibu]

Erik,when I use my air brush in a gravity mode. I use a lower pressure around 15/20 PSI. Although I dont have access to Zero paints.I have used Scale finishes with excellent results. Like yourself I have had an Airbrush for many years and I enjoy getting out in the shop and being creative.

[CadillacPat]

Well then you will have to explore your creative side until you figure out how to use an airbrush, related materials and techniques required. Or you could just quit.

I have to post on behalf of Junkpile's response for you to Practice, Practice, Practice. For the tiny almost negligible amount of info you gave concerning your problem, Junkpiles response is both succinct and appropriate.

There is absolutely no big secret in AirBrushing whteher using Enamels, Acrylics, Lacquers or Automotive Urethanes, i.e., proper mixture, primer, air pressure and distance from object.

You do actually say you can't remember when the problem started only that it began "sometime ago".

The AirBrush is a very simple tool and it's use is quite self explanatory if you just pick i t up and try it.

CadillacPat

[JunkPile]

Thanks for the back-up Pat . I appreciate it.

[sbk]

Art pretty much nailed it. Air pressure that high will cause the roughness in the areas you describe. Trying thinning it until it shoots out nice & wet at 20 psi.

Personally, I have always overthinned paint. It may take more coats to get coverage, but there will be less sanding & polishing to get to smooth.