Airbrush clogging

Sounds like the infamous "tip dry"—Tamiya paints are notorious for this, although any paint can have the problem, especially acrylics in low humidity conditions.

You may need to up your amount of thinner, but the best fix is to:

get some needle lubricant. Badger sells one they call "Regdab Needle Juice," but there are others, too.  

get and use some acrylic retarder, produced by Golden, Liqutex, Createx, etc. and sold in most artist's supply outlets. One bottle lasts a lifetime of modeling because you use about 0.1 ml per  2 ml paint. 

First clean the brush of all old paint residue.  If using lacquer thinner to clean, make sure it is ALL dry before introducing acrylics into the brush. Thin the Tamiya @ a 3:1 paint thinner ratio using Tamiya thinner which has a retarder built into it. Adjust your pressure to at least 20 psi line pressure and balance from there.  Keep us posted.

E

3:1 should be plenty thin enough. More thinner is usually better in terms of getting it through the brush.

Also check for contaminants. The Tamiya paint and thinner will be compatible with each other, but there may be something getting into the mix and cloging up the drain, so to speak.

BTW, you do strain the thinned paint before it goes into the airbrush, right?

Triarius wrote:

BTW, you do strain the thinned paint before it goes into the airbrush, right?

I've never strained paint in my life, and haven't (knocks on own forehead) had any problems yet! 

Bill, you must lead a saintly life…

I always do. Sometimes there's nothing on the strainer, sometimes there is. My process is to strain it into the mixing cup, then wash the thinner through the strainer. This tells me a lot about the condition of the paint. Once or twice, it's saved a lot of grief.

And one serious clog, especially if it clogs and then lets go, is enough to justify the small effort.

Chris, I commend your dedicated stirring! Even I don't stir that long!

Triarius wrote:

Bill, you must lead a saintly life…

That's me, Saint Bill! My paints don't lift, my decals never bubble, my kits always fit perfectly, yeah right! I've spent so much time knocking on my forehead it's built up an additional layer of bone (wood?). The only time I've experienced anything like a clog in my airbrush (Badger 150 or 100 LG with the medium needle/tip) is when I've used Tamiya metallic paints, the metallic particles tend to clump unless stirred regularly.

Sounds like you need to clean them.  If a good cleaning doesn't do it, then the needle bearing could be gone.  Badger will replace the needle bearing for free.  If you do decide to clean them, water will not do the trick on dried paint.  You'll have to use a solvent of some sorts.

E

1. Consider the relatively low cost of a good, new airbrush. Then:
   
2. Disassemble them completely. If something is stuck, leave that but get them as much apart as you can. Remove all nonmetal gaskets and set aside. Plan on replacing all of these, since the brushes are old.
3. Soak the metal parts in DOT 3 brake fluid overnight. Don't leave this where small children or pets can get at it. Disassemble stubborn parts from step two.
   
4. Wipe and scrub any remaining paint from the parts. If something is really stubborn, try acetone (adequate ventilation!!!!) Wash parts in hot, soapy water.
5. Inspect the parts for evidence of wear, corrosion, pitting, etc.  Consider the relatively low cost of a good, new airbrush. Replace as necessary.
6. Reassemble with new gaskets, seals, and replacement parts.
7. Attempt to use. If successful, you're done. If not, proceed to step eight.
8. Consider the relatively low cost of a good, new airbrush.

1. Insure that you have a plentiful supply of air.  No air blowing, no paint spraying.
2. As Ross said, COMPLETELY disassemble the brushes (remove the air valves!) and soak everything that is metal (no o-rings!) in solvent overnight.  I'd even disassemble the air valves and soak the metal parts (NOT the o-rings) in solvent.
3. Look at the airbrush from the front.  At the bottom of the body there is a hole drilled going to the air valve chamber.  Run a piece of wire down that hole to insure it is clear.  That supplies air to the head.
4. The head will have three or four holes in it that are visible when the crown is removed.  Insure that those are clear.  They provide air to the front of the airbrush to pull paint through the nozzle.
5. Reassemble correctly.  If you have plenty of air they should spray properly.  If not take them to a friend's house who has plenty of air and see if they work there.  If not go back to step 1.
6. Call Badger.  I have heard of cases where they refurbished Badger airbrushes for less than the cost of a new one.
7. As Ross said, consider the relative inexpensive cost of a new airbrush.

 PS ... Never strained paint in my life either, and I'm too old and too tired to start now.

If you want one brush to do it all, I recommend a Thayer & Chandler Omni 4000. I love this thing!

But take your time—there are many good airbrushes available. There have been several threads on airbrush purchasing recently—last 6 months or so. Search for them—more good advice than you can shake a hose at… 

Ross and Scott are dead on with the recommended cleaning regimen.  If you prefer not to use brake cleaner, remember, lacquer thinner is your friend. However, always use proper safety measures no matter what you use.  A lot of us learned this the hard way; no matter what new or "better"  brush you buy, without a good cleaning regimen, it'll stop spraying like the old brush in a heartbeat.

E

As Bill said, just because paints use the same general solvent, or even binder, does not mean they are compatible. Acrylics slightly more so than enamels—but you find the same problem when trying to combine lacquers and enamels, for example. As a general rule, I never mix paints of different brands without testing for compatibility, first.

 The compatibility of Gunze and Tamiya is possibly better than that of Tamiya and Model Master or PollyScale, but you will have to try each combination separately. I don't use Gunze—just a preference, I know people who won't use anything else. Both Gunze and Tamiya appear to have fairly complex formulations, but from what I recall, both are alcohol compatible (isopropyl, 90 percent).

To test compatibility, mix equal amounts of each paint in a small, glass, sealable container (old paint bottles, if thoroughly cleaned, are fine.) Thin them with a reducing solvent compatible with both. Let them sit for at least three days, then strain them. The results should be obvious—anything less than perfect mixtures without lumps or strings means that they are incompatible.