Hand Dispensing: Why use thumb plungers?
Dating back to the 1850s, the hand syringe remains the best way to dispense one off shapes and locations. These are ideal for rework, prototype builds and other needs where materials are needed in random location.
Loading the syringes can be done from the bottom or top. Normally loading from the top is easier, and loading from the bottom is better for air entrapment.
There are adaptors to transfer materials from large syringes to small one. Often the air bubbles can be removed. There are 2 comon ways: 1. Removing the plunger and tap - on a hard surface - to drive the heavier fluid down and the lighter air up, 2. centrifuge the air out. A centrifuge is powerful and the normal amount is 10-20 seconds at a moderate speed. You know when you have done too much, because the fluid will separate.
For more consistant and faster dispenseing an air over system is normally used.