Efter trehundrafuttifjorte airbrush-session med krånglande spruta googlade jag och hittade följande eminenta sida där Don i detalj går igenom hur man ska rengöra sin spruta och varför den beter sig som den gör https://sites.google.com/site/donsairbrushtips/
Jag frågade Don om jag fick kopiera texten för att inte glömma bort den, så här är den nu med Dons benägna tillstånd:
A lot of people will tell you that all that is needed to clean an airbrush is to flush it out with an appropriate thinner until it sprays clear. My experience is that this doesn’t always work. Sometimes I would find the needle stuck the next time I went to use the brush. I suspect a little paint leaks inside the needle bearing and drys. So, I always remove the needle and wipe it with a little thinner. This only takes a minute, and it solves the stuck needle problem. I also use an old paint brush to clean the front surface of the nozzle.
I keep a special bottle of thinner for cleaning, and pour a small amount in a glass cup for use. When I’m done, the excess goes back in the bottle. By the next cleaning, most of any pigment has sunk to the bottom. As a last step in cleaning, I always spray a little really clean thinner.
I usually go ahead and remove the head and wipe out the body and tip with thinner too. It’s very easy to do on the 155, it just takes a couple minutes more, and I’m sure of having a clean brush. You can use an inter-dental brush for this, or I’ve found that a pipe cleaner fits nicely in the front and bottom openings in the body of the 155, and does a good job. A pipe cleaner can leave little bits of fuzz, so after using one, I squirt a little thinner through the brush with an eye dropper to wash out any stray fibers. I also use a pipe cleaner to clean the paint cup spout.
One way to clean the tip is to take the corner of a paper towel and roll it into a point. Then dip it in thinner and poke it in the large end of the tip and twist until you can see a bit of it on the small end. I learned this on one of the forums.
If you are using a water based cleaner, it might be easier to insert the towel dry and then add the cleaner. Water tends to soften the towel a lot.
To hold the tip for cleaning, I modified a wooden clothes pin by cutting it off and filing a little groove next to the ends. Using it, I can easily pick up the tip from the bench and hold it securely. It eliminates a lot of fumbling.
Before re-installing the tip, I lightly rub the opening in the airbrush body that the tip fits against with a small piece of bees wax. It’s just a little insurance to guarantee a good seal and avoid bubbles in the cup.
Some airbrush parts have very fine threads. Be careful not to cross thread them. If your airbrush is the type with a tiny screw-in nozzle, be very careful not to over-tighten it. In fact, if you have the tiny screw-in nozzle, it might be better to just leave it in place.
Make sure the trigger is fully in place before trying to run a needle through it. When I insert the needle into the body, I hold it loosely. That way, if I miss the hole, the point won’t be damaged. I push the needle in until I can feel it bump against the nozzle. There should be some drag going through the needle bearing. You don’t want to push too hard or you may distort or split the tip of the nozzle. I tighten the needle chuck and work the trigger to see that it feels right. For me, the needle is the first thing out and the last thing in.
As a final touch, I turn the brush upside down, put a little clean thinner in the paint supply hole and shoot it out. And that’s all I ever do. I’ve read that some folks regularly disassemble their brushes and soak them in cleaning solutions and some even buy ultrasonic cleaners. I personally have never seen a need for this.
Cleaning doesn’t have to be a hassle. It’s just a matter of figuring out where the paint goes and finding the easiest way to get rid of it. If it’s a through passage and the solvent is strong enough, aggressive flushing might do. I’ve found that a pumping action with an eyedropper works pretty well. If it’s a blind passage, like behind the cup, a quick swab with a tiny brush or pipe cleaner might be needed. Each of my airbrushes has its own quirks, and I alter the process to fit. A quick inspection with a magnifier and strong light source will show if it’s good enough.
Back flushing means holding something like your finger or a paper towel over the nozzle of the airbrush while pressing down and pulling back slightly on the trigger. This forces air back through the tip and into the paint cup, causing bubbles. It is commonly recommended as part of the cleaning process. Supposedly, it breaks paint free and helps to wash it out. But here’s how I figure. Yes, it will cause bubbles in the paint cup. But, in the narrow passageway leading to the nozzle, all you’re going to get is dry air blowing through. To me, this does not seem like a useful thing to do. Anyway, I’ve tried it and I can’t see where it makes any difference, so I don’t do it. I feel like I get better results with a pumping action from an eyedropper in the paint supply port of a siphon fed airbrush, or the cup of a gravity fed brush. But, try it yourself and see what you think. I do sometimes back flush to mix paint and thinner in the cup just before painting though.
Please note: Since I first wrote this section, I’ve come to realize a value of back flushing that I had not considered earlier. In most airbrushes, there is a narrow channel between the needle seal and the internal paint chamber. This channel can collect paint. By back flushing during cleaning, some solvent could be forced into this space and help keep it clear.
If the shape of your airbrush nozzle makes it difficult to back flush because it has a crown or forked design, try holding the rubber bulb from an eyedropper over it.
When I bought the brush, I also bought some store brand airbrush lube and applied it to all the moving parts. After some time, I noticed that the trigger action was a bit stiff. I found that the lube had gotten sort of gummy. I suspect it was nothing but glycerin with a little food coloring. So I cleaned everything and put a tiny bit of sewing machine oil on all the metal parts that rub together. I usually don’t lube the needle because I decided that lubing Teflon was kind of redundant. The trigger movement has felt fine ever since.
I have monitored several airbrush and modeling forums and I’ve seen a lot of postings about airbrush problems. People try to help, but sometimes it’s pretty tough. How do you respond when somebody writes: “My airbrush doesn’t work. What’s wrong with it?” Okay, that’s an exaggeration, but not by too much. So if you ask for help, try to give as much information as you can. Include the airbrush brand and model, the type and brand of paint, the air pressure, exactly what the symptoms are, and what things have you tried so far. I know this is just common sense, but many people just don’t think about it. And, if you do get help, please come back with the results, and maybe even say thanks. Not only might you be helping someone else with the same problem, but the person who helped you might be more inclined to help you or others in the future.
You will probably be advised to clean your brush again. This is a pat answer, and often it works. And you may be frustrated because you know you’ve cleaned the darn thing several times already. But it doesn’t take much dirt to mess up an airbrush’s operation. A tiny piece of lint can do it. I would suggest you use a magnifying glass (the stronger the better) and a good source of light and really examine all the parts.
Some airbrush problems are really paint problems. Before you blame the brush, see how it works with plain water or thinner. Paint has to be really thin to work in an airbrush, especially if it has one of the smaller size nozzles like .2 or .3mm.
If you haven’t read my Basic Stuff page, you might want to have a look at it. It may make the information below easier to understand. As you can see if you’ve read that page, the airbrush is basically a pretty simple device. But it is a precision device, and tolerances are tight.
One other thing; spare parts are nice to have, especially the needle and nozzle. You can quickly eliminate these as the cause of your problem by swapping them out.
So what kind of things can go wrong?
No air comes out
Obvious question: Did you disconnect the air line from the brush and check that your compressor or other air source is supplying plenty of air?
Some trigger mechanisms are tricky to install. Are you sure yours is in right? Can you feel the air valve spring when you press the trigger? If you remove the head assembly, there is a little hole in the main body where air should come out when you press the trigger. See the photo on the right for its location on the 155. If air does come out, then the problem is probably something clogging the head assembly. Hopefully, there is no dried paint blocking this little hole. If there is, you may have to soak the body in something to soften it so it can be blown out. Be sure to remove the air valve assembly before doing this.
If air doesn’t come out, then the only thing left is the air valve assembly. Be very careful if you dismantle it. There are some very small parts and a tiny spring. See the photo on the right of a Badger air valve assembly. There is probably a little rubber O-ring that could be damaged. If you’ve gotten lacquer thinner on it, it may have swollen enough to jam. It may return to normal if you let it air out for a few days. If not, you may have to replace it. Make sure all the parts are clean and work smoothly. Many advise applying airbrush lube. I don’t, but I guess it couldn’t hurt.Sticky Trigger For some reason I seem to see this problem most often from Iwata owners. They usually write that they clean the air valve assembly, and it works OK for a short time and then begins sticking again. Sometimes they mention finding paint residue in the valve. If there is paint, where did it come from? The only possible source is through the needle bearing. Either they are pulling the needle out when there is still paint in the brush, or the needle bearing is leaking. In some airbrushes there is an adjustment on the needle bearing that might stop a leak. If not, or if that doesn’t work, the bearing needs to be replaced.
In some airbrushes, the trigger pin passes through a rubber o-ring. It may need a tiny bit of lubrication. Most users and manufacturers recommend regular airbrush lube.
Note: I got an e-mail from Rick Bradley. An Iwata technician told him to use the back of the airbrush needle to insert lube in the trigger pin opening. Of course, you have to remove the trigger to do this. Thanks for passing that on, Rick.
Bubbles in the paint cup
In order to create a vacuum to pull paint out of the brush, the nozzle has to protrude just a tiny bit past the front of the spray regulator. If it doesn’t, you can get pressure instead of a vacuum here and air will blow back into the cup or bottle. This can be a problem in airbrushes with rubber O-rings in the head assembly.
This can be caused by the same things listed above for bubbles in the cup. For a siphon fed brush, it can also be caused by a worn needle bearing or seal. See my page on replacing the needle bearing for this. Make sure it isn’t a paint problem.
A common problem is that paint will spray as soon as you press the trigger for air, even before pulling back the trigger. This happens because of an imperfect seal between the needle and nozzle. It sometimes doesn’t show up at lower air pressures. It can be caused by a small particle of dirt or dried paint in the nozzle, or a needle or nozzle that is not perfectly round. At low pressure, there is not enough vacuum to overcome the paint viscosity and pull it through the small opening. When the pressure is increased, so does the vacuum and paint is expelled.
Sometimes, it can be fixed by rotating the needle in the nozzle with slight pressure. Some people apply a little pressure to the back of the needle when they tighten the needle chuck. But, you have to be careful not to damage the nozzle. Soaking the nozzle in a solvent that dissolves dry paint may also help.
Another possibility is that the needle seal is too tight for the trigger return spring to fully seat the needle. You may be able to adjust the trigger tension or the needle seal. You should feel a little drag when you install the needle, but it shouldn’t take much force.
If you have polished the needle, you may have caused it to go out of round. If you have spares, try swapping parts to find the culprit.
Air but no paint
Maybe your paint is too thick or has lumps. You could try cranking the air pressure up a little to increase the vacuum, or you could see if the problem goes away when you spray plain water or thinner.
Sometimes people forget to tighten the needle chuck. They pull back on the trigger, but the needle doesn’t move; easy to fix once you notice it.
Sometimes, if the needle is stuck from dried paint, the needle chuck will slip when you pull back the trigger, even though you tightened it. So, check to see that the needle is really moving.
Make sure there is a vent hole in the cap of your siphon bottle or paint cup lid. Otherwise a vacuum will form and stop the paint from flowing.
In a siphon airbrush, a really leaky needle seal or needle bearing can cause this. To check for this, turn the airbrush upside down and put some water in the paint inlet. If it sprays OK in this position, then the seal may be bad. It may be adjustable or it may need to be replaced.
Bad spray pattern or spatters
Take a close look at the needle and nozzle. A bent needle or cracked nozzle can cause this. Acrylic paints seem to cause some problems. I’ve never used them so I can’t comment. You can feel for a tiny burr on the tip of the needle by running your fingernail lightly along it.
Works for a while, then doesn’t
I see this once in a while on the forums. The user says the airbrush works fine for a while, but before they can finish, it begins spraying bad or clogging and they have to stop and clean it. They often blame the airbrush.
Here’s what I think. An airbrush is made of hard stuff, like metal or hard plastic. It isn’t very likely to change much during a painting session. If it works when you start, it should work till you finish. So, what does that leave? The Paint! I doubt whether anyone sees this problem spraying ink.
Paint can dry on the needle during use, especially if it is acrylic, and especially if the user is in the habit of lifting off the air before returning the trigger all the way forward. This is called tip dry, and is a fact of life when using acrylics, and even somewhat with enamels. Some airbrushes are more prone to this than others, but I believe they all have it to some extent. You can use a brush or Q-tip and solvent to remove it or, like many artists, use your fingernails to pick it off. Sometimes a blast of paint on some scrap will remove it. If you watch many airbrush videos, you will see artists doing this often.
Another likely cause is lumps in the paint. If you don’t keep your bottles clean, paint can dry around the mouth of the jar. Then, when you stir or shake, little bits can fall into the bottle and end up in your airbrush. An airbrush does not like lumps. Here again, this is more likely with acrylics because of their fast dry times.
So, before you blame the airbrush, clean it well, try some fresh paint or ink and see if the problem goes away.
Rough finish, orange peel, overspray, etc.
Sorry to tell you this, but it probably isn’t the brush.
A rough sandpaper finish can happen if the airbrush is too far away from the object. The paint droplets partially dry before they hit and pile up on the surface.
Orange peel happens when the paint droplets don’t flow together to form a smooth coat. Try slowing down and applying the paint a little heavier.
Runs happen when the paint is applied too heavy, or it’s too thin. Thinner paint needs a thinner application.
Speckles are sometimes done on purpose to create a textured effect. Then, it’s called stippling. It happens when the air pressure is too low for the viscosity of the paint. It can also be done by placing something in front of the nozzle to bounce the paint particles around and scatter them.
When the paint makes a splat, it’s called spidering. It happens when the paint is too thin, the pressure too high, or you are too close.
It just doesn’t spray like it use to.
Two parts that are very critical to the way an airbrush sprays are the nozzle, or tip, and the needle. Over time, the nozzle can be deformed by pressure from the needle and take on a slight trumpet shape. Both the needle and nozzle can wear from abrasion of paint particles. And, the needle profile may have been altered by straightening efforts or polishing. If your airbrush still works, but not as well as it once did, you may find that a needle/nozzle replacement will bring it back to its old self.
Air Hose Leak
If you have a leak at either end of the air hose, don’t bother trying to stop it with Teflon tape or sealant on the threads. They are not meant to seal. The seal is inside the hose connector. In the Badger plastic hose, it is a cork washer. In the braided hose, it is a smooth metal surface. In my Iwata compatible Master hose adapter and Paasche hose, it is a rubber O-ring. In all three cases, it only works if it presses against smooth surface. So, the end of the airbrush connector and the compressor pipe must be smooth. A thin film of bees wax will help a lot. If you still have a tiny leak that only shows up with soap bubbles, don’t worry about it. Percentage wise, it’s insignificant.
If you look dead straight on at the front of an airbrush nozzle and pull back on the trigger, you may find that the needle pulls to one side. Some people notice this and think they have a bad airbrush. Not so. Here’s the problem. An airbrush needle is only supported at two points, the needle seal and the needle chuck. The distance from the seal to the front of the nozzle can be in excess of one inch. The nozzle diameter is a fraction of a millimeter. That’s an awful small target to hit. So, it is common for the needle to end up slightly offset. Fortunately, it turns out it doesn’t really affect the spray pattern. Unless it is so far off that it binds, it doesn’t matter.
What does make a big difference is the centering of the nozzle within the spray regulator. If this is off very much, the pattern will be distorted.
In general, when you first get an airbrush, look it over carefully and study the parts breakdown so you understand how it works. It’s pretty clear from some of the questions that are asked, that many people don’t. I remember one instance where a fellow couldn’t get any paint out of his new brush. Then he discovered that he hadn’t removed the protective cap. At least he was man enough to admit it.
Also, if you’re still stuck, consider contacting the manufacturer or dealer. My only experience is with Badger and Coast Airbrush, and they both have excellent customer support.
I got an e-mail from Alan Houtz about the sticking Iwata trigger. He said he was used to removing the needle on his siphon fed brushes even when there was some paint in the cup, and never had a problem. Then he got an Iwata gravity fed Eclipse HP-CS. Without thinking, he did the same thing and paint leaked back into the air valve and trigger assembly. I guess it made a real mess. He had to completely dismantle the brush and clean with solvent and micro brushes. He says there is an internal brass sleeve in the air valve that has to be removed for cleaning. To remove it he used a Q-tip soaked with thinner. He inserted it in the valve and used a little side pressure to remove the sleeve. After a thorough scrubbing, his trigger has worked fine ever since. So, I guess the lesson is; don’t remove the needle until the cup is rinsed clean.