From Fab @ Home
Loading a Syringe
One key to successfully using the fabber is making sure that there are no air bubbles in the syringe. With air mixed in with the building material, the flow from the nozzle tip is not uniform, and results in poor dispensing. Some methods for avoiding air bubbles are outlined below.
Materials from Tubes
In the case of materials that come in tubes, like silicone, the easiest way to avoid air bubbles is to load the material through the tip. With the plunger inserted fully, the material can be pushed in from the tube, and will force the plunger backward as the syringe fills. As you can see in the rightmost picture below, sometimes a little extra force is needed to load the syringe this way.
With silicone in containers that use a caulking gun for extrusion, it is best to unscrew the tip from the tube, insert the stub into the top of the barrel, and rapidly extrude material into the syringe until it reaches the tip.
Getting Out Air Bubbles
If the above method will not work, you can slide a wire down alongside the plunger. As the plunger is depressed, the air can escape through the gap provided by the wire.