Airbrushing: Weird spotty effect

Tools, Techniques, and Reference Materials Painting and airbrushing
1

Hello everyone!

I hope someone can help me out with an annoying issue I’m having with my airbrush. I am a complete beginner so there is probably something obvious I’m missing.

I have recently bought my first airbrush and compressor, a Badger Patriot with a dual tank Badger compressor. I use Vallejo Model Air colors with Vallejos Airbrush Thinner.

I have been trying different configurations and thinning ratios but almost always get this weird spotty, grainy effect. Like the airbrush tool in MS Paint. The example in the picture was made att a PSI around 10-12 with a thinning ration of 1:1 Vallejo Model Air and Vallejo Airbrush Thinner. The effect is reduced by increasing the PSI to around 20-25, but according to different tutorials, that is way too high (for scale models at least).

What am I doing wrong? The relaxing hobby is turning into something very frustrating and confusing. I hope someone can help me out! Thanks!

2

I find the easiest way to get the right mix is to add thinner to the cup first and then add paint a little at a time until it sprays the way you want. This works for any kind of paint. I add the paint with a Tamiya paint stirrer. You should be able to spray at any of the pressures you have tried, but most people use somewhere in the 15-20 range.

Jay

3

Couple of thoughts…

1:1 is probably too much thinner. Vallejo Model Air is designed to spray unthinned. Lots of folks add wee bit of thinner, sometimes I do.

I find Vallejo sprays better around 25 psi, which agrees with your result. It’ll work at 10-12, but it has to be thinned just right and the tip can dry up very fast.

Sounds like nice airbrushing setup you have there!

4

Greg is spot on, Model Air is pretty much able to be sprayed straight from the bottle, if any thinning is required I find it to be very little. Model Air does require a thorough mixing, as does all paint really. Their instructions say to just roll the bottle between your hands prior to use, I find that to be totally inadequate for pre-use mixing.

A) When I began using it I had very inconsistent results, initially I thought it was just a poor paint product. But having used Model Master and Tamiya paints in the wide mouth jars, I was aware that a simple shake was not capable of a thorough mixing. They required a stir with a stick to get the settled solids off the bottom, then a good mix with my Badger electric mixer to completely blend all of the ingredients.

B) I took a bottle of Model Air that I had rolled and shaken as they instruct, pried the top nozzle off by just pressing sideways until the edge lifted and I was able to pull the nozzle off. I stirred the bottom with a stick and out came a huge glob of the solids that had settled. So indeed, just shaking any paint is not at all a complete mix of all of the contents.

C) Once the settled solids were stirred off the bottom, I placed a small stainless steel nut in the bottle and replaced the nozzle, gave it a good shake and re-tried using it in the airbrush. It worked perfectly, just as the product is advertised. (Don’t use ball bearings or BB’s, being round they will settle into the nozzle when bottle is inverted and block paint flow when pouring out.) No need to ask how I know that.

If you’re sure that the AB is completely clean after last use, then use the thorough mix as suggested, try pressures from 10 to 20 psi and see what you think about your results then. Above all else, do not use alcohol mixed with Vallejo paints, it WILL react negatively and leave a real coagulated mess. Same applies to cleaning after use.

As an add on, if you haven’t already, have a thorough look at Don’s Airbrush website. You’re AB is covered in there, you’ll find a wealth of accurate information about airbrushing in general, cleaning included. Highly recommended, very well worth the time.

Check back in with results if inclined, we all like to hear about how newcomers do with practice.

Good luck

Patrick

5

That’s a clever idea re the stainless nut as an agitator, Patrick.

Do check back, Ola. Patick is right, feedback is great.

6

As mentioned, stir, stir and keep stirring. Shaking a paint bottle doesn’t do it unless it’s Alclad. Generally all the pigment globs at the bottom of the bottle and needs to be blended with a stick. I bought a ton of thin flat sticks at Michaels for a couple of bucks and use them for stirring paint.

I’m an enamel user and cut down my flat enamels close to 50% and gloss enamels slighly more than 50%. My ranges are from 4-8 psi for very fine mottling to 10-15 psi for regular painting. Each AB will perform differently so you have to play around with the formulas.

The few times I have sprayed acrylics as in Tamiya, MM Acryl and craft paints I see the need to increase the psi to get consistent performance. Usually in the 20-30 psi range. I read somewhere in FSM of a couple of modelers that spray at 45 psi for tight thin patterns using acrylics. I for one have a lot of performance issues spraying acrylics so I rather use enamels which for me, perform like a champ every time.

I use an Ewata Neo, Badger 150, Badger Renegade and Badger Anthem and they all perform slightly different from each other. You need to experiment and take notes as to what works.

7

Wow, I am so grateful for your advice!

Right before reading your message I tried spraying some very thinned paint at 20-30 psi with varying results. I also tried not thinning, which gave me horrible results, as well as running on 10 psi.

I confess to being unthorough with agitating the bottle beforehand so maybe that is where my problem lies! I will most definitly report back when I’ve tried your method!

Thanks!

8

Okay, so I did some experimenting yesterday. I stirred the bottles thoroughly with the back of a brush as well as adding agitators (I used the heads of screws for this).

My results were still pretty inconsistent. I still most definitely had to run the compressor on at least 20 psi, or the grainy effect would persist. I also found it to give a smoother finnish with thinner added.

Several colors I tried worked well enough. However, the grey polyutherane primer from Vallejo turned out to be really grainy, as well as Citadel’s Caliban Green. Those were the colors I wanted to use on my model and the result was not good at all. The green surface of the model has tons of tiny spots instead of a uniform, smooth surface.

Keep in mind that I ran the compressor on about 35 psi, had agitated the color thorougly and thinned it down to a milky consistency.

Does anyone have a clue as to what I should do? I really don’t want to have to sell my equipment …

9

Have you torn down and thoroughly cleaned your airbrush? That’s my first step when I have unexplainable problems.

Also, could you tell us what cleaner you use to clean your airbrush? This could be an important part of the problem, so if you could mention anything you might be using.

One of Vallejo’s strong points is it’s self-leveling properties. You should definitely not be getting a bumpy finish. Even as thick as the polyurethane primer is, it has always laid down very smoothly for me. (I’m not a fan of their primers, but that’s besides the point).

Don’t give up yet, this really should not be happening.

10

I’m kind of at a loss, trying to think of what the problems could be related to. It appears contamination of the paint in the bottles seems unlikely, as you’ve tried multiple bottles with the same results. Next would be possible contamination of the agents you use as reducers, but again that seems not a strong suspect.

I guess it takes me back to the airbrush, so let’s think it through. If the airbrush worked well to start and produced good results, now has problems, then it’s a good starting point for ruling out the paint.

The airbrush might have had an o-ring or washer get damaged along the way, so when you try to spray do you see any bubbles come up in the bottle or cup? If a nozzle is not seated well, then it can also lead to improper spray consistency. Not to be insulting, but are you quite sure the AB has been fully and carefully cleaned at the completion of every job you’ve done with it? A stray bit of dried paint, cotton bud residue or anything else can raise heck with an AB’s function.

Did you take a good look through Don’s Airbrush website? Your airbrush is one of the examples used, and there is a great section on cleaning of the AB.

Above all, don’t be discouraged and bail out, this is a quality AB, whatever kind of tummy ache it’s experiencing CAN and WILL be resolved, just a matter of sticking with it.

I had a Paasche VL for years, worked well but I hated the two part trigger when it came time to re-install it after teardown. Paasche had a replacement one part trigger, it required a different air valve. I bought both, installed them and the AB would not work. I fought it for some time, gave up and sent it back to Paasche for repair.

I had left a tiny o-ring behind in the air valve port, fault was mine, but my frustration was easily resolved by just having that mistake fixed. Loved the old VL after that, but for the time it didn’t work I hated it. Stick with it, you’ll get there. Let us know what you find.

Lastly, tearing down and re-assembling an AB a few times will teach you a lot, about fit and function of an airbrush. Familiarity is a real key to using and maintaining an AB, try that and you may find something that is just not fully adjusted or fitting properly.

Best of luck with it.

Patrick

11

Thank you all once again for your wise replies! It really helps to mitigate my anixety about this whole thing.

I have found that, when cleaning the airbrush with water, the water leaks out between the nozzle and the body of the airbrush. There is also a very thin layer of paint dried up between the threads.

The paint itself can’t be the problem, since I have been having issues from the very first moment I used the airbrush. However, could it be that the threads of the nozzle is a bad fit with the rest of the airbrush?

12

One other thing comes to mind, distance from the airbrush to the object to be painted.

For broadcast base coats or primer coats, when I want to lay down plenty of paint in each pass, I might use a pressure of about 18-25 psi. I would likely have the AB tip about 1/2 to 1 inch from the model, just an estimate.

Remember, it is a dual action AB, you have to pull the trigger back further for increased paint volume. Is it possible you’re going on too dry by not pulling the trigger back enough?

For finer work, when I might be filling in spots or placing camo borders, I would use about 12-18 psi and be only 1/8 to 1/4 inch away.

Just a suggestion, but if you’re holding the AB as you might a spray can and be several inches away from the model, you would expect to see a very spotty and rough texture. It would appear very “foggy” or “misty”, also the rough texture would be related to the excessive distance, resulting in the paint particles drying partially before reaching the surface to be painted. At this point, excessive distance is what I’m thinking.

Try using some scrap plastic for test spraying, big soda bottles work well, if none availabe use some shiny, printed cardboard. Anything porous won’t be suitable, it is too absorptive and won’t produce results that give you visual confirmation, about how the paint is laying down, (or not.)

Try getting closer as suggested, experiment and do lot’s of spraying at various pressures, distances and thinning ratios. If nothing is out of adjustment within the AB, then maybe this will give you something to go on. Hope so.

Please let us know, I’d like to see this get sorted and you off to the satisfaction of using an airbrush. Whole great big huge heapin’ gobs of fun to be had.

Patrick

13

I’m at a loss too but the more I think about it, I keep going back to bad paint or contamination from the AB. A while back I sprayed the underside of a Spit with some Humbrol paint. It was over 30 years old but it stirred and blended perfectly fine. I sprayed as usual with my regular thinning formula and psi setting. It sprayed just fine and looked good after it dried. I like to lightly buff out flat paint with a soft cotton rag just to get a smoother finish and the paint came right off like a powder. This had never hapenned to me before. Next day I bought a fresh tin at my LHS and sprayed that one as usual. This time the paint did not come off so I wonder if you are experiencing the same issue I did.

14

Thanks alot for your replies!

The distance it definitly something I have to experiment with. I can’t say for sure how far away I hold the airbrush from the model, but I’m pretty sure it’s more than an inch. At least a couple of inches I think.

Next tuesday I’m going to visit a friend who recently bought the exact same airbrush as me. I will bring my paint bottles, my airbrush and conduct some experiments and compare our brushes to see if he has the same problem.

Thank you all again for helping me sort this out! :slight_smile:

15

I dont like vallejo I posted on this forum about this stuff Chrisk-k informed me on liquitex flow aid mix in small .5 oz plastic bottel 1part flow aid to 4 part distilled water use this with the paint to thin down and it works but I still dont like vallejo. you can get flow aid at hobby lobby oh once the mix is right I spray at 8-10 lbs air

16

Ola, I missed the fact that you gave, about the leak being between the nozzle and the body. When I re-assemble after cleaning I use Badger’s airbrush lube on all threaded parts. I RARELY experience leaks, if I do it’s bubbles from air going back to the cup, that only happened once, when a nozzle developed a crack. Don Wheeler correctly says using some beeswax or Chapstick, (lip balm,) on the more critical parts can often effectively seal against leaks. But you’re describing water, so I just don’t know enough to address that.

Seriously, I recommend you have a look at his website for reference, then you can use the link for contacting him for specific suggestions and diagnosis of these issues you’re having. He’s a great guy, vast knowledge, he’ll help you out. He sure was the biggest part of my airbrushing improvement and confidence. He does not sell anything, or charge to help people out.

Keep us posted and don’t be discouraged, my first several attempts at airbrushing were terrible, for a while I felt sure I didn’t want any part of it. Then, when I got things sorted well enough to use the AB with some degree of proficiency and confidence, it became a 50+ year hobby with great enjoyment.

Patrick

17

I don’t like Vallejo, either. I’m stuck with about 30 bottles of Vallejo Model Air and Primers, so that’s the only reason why i occasionally use them.

In contrast, I love Tamiya acrylics. They always work regardless of psi values and airbrush types.

18

I finally got it!

I went to the store where I bought the airbrush and asked them to show me how to use it properly, without the stippling effect.

Turns out, I’ve been using too thick paint. Vallejo air-colors are advertised as being usable “straight from the bottle”, which made me feel like a madman when thinning it 50/50 with airbrush thinner. My Vallejo colors needed a lot more than that, however, so when the store owner showed me his preference for paint-thickness the results were fantastic!

The coats are very thin, but the edges of the pattern was amazing! So I guess that solves my initial airbrushing issues!

19

Are you sure you are using Vallejo Model Air and not Vallejo Model Color?

At any rate, glad you got things sorted out.

20

Yes, I’m positive!

My friend, who has the same compressor and brush as I, also had the same effect with undiluted Vallejo Model Air!