Saturday, March 28, 2015

Singer Restoration Saturday - Airbrush Cleaning

Yesterday, I was trying to put one last black basecoat on the bobbin winder parts for the Model 127 #1, but the airbrush would not behave -- the airflow was weak and the paint kept spitting in too-large droplets.  So, once again, it is time to break it all down and give each part a thorough cleaning.

Airbrush in need of cleaning
A word of warning: Many of these parts are really small. Be careful to put them in a safe place while cleaning and do not drop them, or you may be ordering another replacement part. 

First of all, you need to unscrew the needle chuck between the holes in the back section, and remove the long needle that runs from the ball at the tail of the airbrush to the nozzle at the tip.

Needle Removed
Removing the needle releases the trigger from being held in place. Take it out by pulling it straight up (if it doesn't fall out all by itself). 
Trigger no longer locked in place

Comes out nice and easy
 With the trigger out, the trigger back lever should be pushed forward to the front of its track.  Gently push it back to the rear end of the track, the cross track should give you room to wiggle the lever free.
Trigger and Trigger Back Lever Removed
To loosen the air valve, use a 1.5mm Allen wrench to loosen the nut at the end.  This is the smallest Allen wrench in the set I have, and some sets do not go this small.

Ready to loosen Air Valve
Once loosened, unscrew the rest of the air valve from the body of the airbrush, using the grip in the middle.  You might need to use a small pliers, if finger strength is not enough to get it started.

Notice how really tiny the nut you first loosened is, and also, the spring from inside the assembly.  Imagine trying to find them if you drop them on the floor! Also inside the air valve are a tiny O-ring and valve plunger (not pictured).
Tiny Parts of the Air Valve
Next, unscrew the Spray Regulator, Spray Head, and Spray Tip from the airbrush body.

Spray Regulator, Spray Head, Spray Tip

Finally, unscrew the cutaway handle at the back of the airbrush, then unscrew the tube shank assembly found inside.

Cutaway Handle removed
Tube Shank Unscrewed
Finally, you are ready to begin cleaning.  Using the appropriate solvent for the paint you have been using, clean out the paint cup and front of the airbrush body. Use a Q-tip or small brush to get down into the bottom of the cup, and the channel, out to the spray assembly. Make sure the air valve plunger moves freely inside the air valve, then re-assemble the air valve, and make sure the plunger still presses in easily and quickly springs back.

Cleaning out the paint cup

Make sure that paint (middle) channel is clean, too
 Now to put everything back together:  screw the spray regulator, head, and tip together on the front of the airbrush; the air valve on the underside; and the tube shank assembly at the rear.

Coming back together
If the tube shank assembly will not screw in all the way, turn its center post while pulling gently, until the post lines up with its channel.  Then you should be able to screw in the tube shank assembly the rest of the way.

Pulling the tube shank assembly post when lined up properly
Pull back on the post again, and work the trigger back lever into the slot at the back of its track. To hold it in place, you can push it to one side while you insert the trigger.

Putting in the trigger back lever
Lever pushed to the side for now
 Put the trigger in the front end of the slot, ahead of the trigger back lever.  Note that the holes in the trigger must face the front and back of the airbrush (the needle will go through them soon). Note also that the tip of the trigger must rest on the point of the air valve plunger.  When properly placed, you should be able to press down on the trigger and feel the plunger move, and then release it and feel it spring back.
In goes the trigger
Finally, thread the needle through the needle chuck, then through the holes in the tube shank, trigger back lever and trigger, spray regulator and tip. When the needle is properly place, the point of the needle will show through the end of the spray tip, visible through the hole in the spray regulator. Tighten the needle chuck, screw on the cutaway handle, and you are ready to go!
Nearly done
Or so I thought.  Even with all this cleaning, my airbrush still would not work!  It seemed like there was not any air getting through, even though the air valve was working fine. Finally, I found the problem in the spray regulator. 

The culprit
It does not show up very well on this picture, but I found a ring of dried paint around the inside of the hole in the spray regulator. This is where the air comes out to spray the paint when you press the trigger (the paint comes out the hole in the tip, inside the spray regulator hole, when you pull the trigger back). When I removed the spray regulator, cleaned that little bit of paint out, then reassembled it, the airbrush worked like a charm!

Susan says I need arrows.  I will rework this post when I figure out how I am going to get arrows on my images.


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