PSI seems to be off

[DMarie]

Hi again, as I was abing today, my ab seemed like it was slowing down. I thought maybe it was clogged so I dismanteled the gun. YIKES! Talk about an anxiety attack! I have a Devilbiss and it is confusing! At anyrate, I noticed that there is a black film as I took out the needle, put it back in, and removed it again. I thought it was paint, but it seemed kindof greasy (?). Now it seems like I have to jack the PSI up but still not much paint is coming out. Argh! This is a very tricky job! LOL

[fontgeek]

What kind of paint are you using, and which model of DeVilbiss brush are you using?

What have you been using to clean out your brush, what kind of solvent?

Have you checked the air pressure to see if it is at the setting you want?

Have you checked your brush or hoses to see if there are any air leaks?

Using a mild soapy solution (Dishwashing liquid soap works great), wipe down your brush, all it's fittings and connections, and the same with the hose(s) and connections, all the way back to the compressor. Then turn on the air. Look to see if you get any bubbling, if you do, then it means you are leaking air at those points, and losing pressure that should be going through to your airbrush.

If it is a Dagr, then it should have the teflon packing/seals. If it is an older brush, it would probably have rubber packing/seals, they are great for most paints and solvents, but you can run into problems if you use urethane paints or their reducers. The reducers typically use MEK as the active ingredient, and that will damage or destroy the rubber packing/seals, it can make it gummy, or just disolve into a black slime, and that would keep your brush from performing the way it should.

If you aren't using urethanes, or are using a Dagr, then I would check to make sure your brush is completely clean, but I would also make sure you have a water trap and filter system on your airbrush setup.
If you get rust or gunk getting into your airvalve on your airbrush, or caught in the air passage within the airbrush, it can screw up your performance.
The black slime or grease you are getting on the needle would be paint remnants or possibly oil or gunk from the compressor.

I had a friend who had the rubber seal that sits at the bottom of his trigger opening give way. He had air and some moisture blowing onto his hands whenever he pushed down on the trigger. While his air was clean, it still let air come up through that opening rather than pushing through the airbrush body like it normally would. If he didn't have air filters or clean air coming through his air line, it would have blown that oil, dirt, moisture, etc. up on the needle and his hands when he tried to paint.
Good luck, and let us know the info and or outcome.

[DMarie]

Hey there! Thanks again for your reply! Yes, it's a Dagr AB. It's a brand new one that I got a year ago, but have just recently started putting it to quite alot of work. I am using the Createx colors and slovent to clean it as well as hot water, and Windex. Yep, the compressor has the water trap and filter and I have been a wreck since taking the AB apart yesterday to clean it. I am going to check for the leak tomorrow like you said. Wish me luck..oops you did! LOL Thanks again so much!

[fontgeek]

The Windex should be avoided other than the initial cleaning of the new brush. Manufacturers used to reccomend it for getting any remnants of packing grease out of the brush, but long term exposure of brass (the body of your airbrush) and chrome to ammonia has the potential for damaging your brush. Ammonia oxidizes brass and can do damage to chrome. If you are cleaning your brush thoroughly when you are done painting, you could probably get away with just plain water, but Createx's solvent should take care of any remnant or stubborn material. Always try to use as gentle a cleaner or solvent as possible, the less additives or things not meant for airbrushing, the lower the possibliity that you will damage your brush or contaminate your paint. Some detergents leave residue, and dry out rubber packing or seals. Many people have had problems using things like Fantastic or 409 in their brushes, often times they don't realize that the damage they are seeing is from the use of those products, but several people have found that the chrome went away from the interior of the paint reservoir when they used them for cleaning or for reducing their paints.

Get yourself into a regular routine for cleaning and maintaining your brush, if you don't already do that. The vast majority of problems people have with their brushes is from not doing a good job cleaning them.

Build a nice kit that has the brushes, solvents and cleaning tools you need to do a thorough cleaning. A kit helps you to have all the tools you need in one place, and those same tools help you to remember all the steps you need to take in cleaning.

For me, I always start from the inside, and once the interior of the brush is clean, then I go after the exterior. That lets me know that when I look at a brush that if the outside is clean, then the inside is too. Doing it the other way around doesn't let you know if a brush is clean without taking it apart first, and you will probably find that you have more paint on the inside than you do on the outside, so if you clean the outside first, then get paint on your hands or tools, that you will get paint on the outside of the brush, and have to clean it all over again.

Just thoughts from the cheap seats.

[DMarie]

Hi again. Ok, no leaks in hose and the brush is clean as a whistle! Thanks for the windex pointer. I am also going to start to dilute my paints to maybe avoid the clogging as much thus minimizing the spitting hopefully. I love this board! Thanks so much for all your help!