Impatient Inventor and I have continued work on the solder extruder. To dispense the solder more consistently, we decided to try using a pump to pulse air into the solder chamber and hopefully thus pulse solder out the bottom of our extruder. This depends on an amount of pressure not possible with our previous nozzle. So, for this version, we opted to use a pipe tee: we will feed solder into a barbed fitting connected to the top, use an aquarium pump to pulse air in into a barbed fitting on the side, and extrude solder through a barbed fitting on the bottom.
Given that we had a bigger extruder head, we needed more heat or more patience. We opted for more heat: we decided to connect four soldering irons to the extruder. To do this, we got the help of a talented welder friend of Impatient Inventor’s. He welded four 1/4″ (the inner diameter of the soldering iron with its tip removed) aluminium posts on the bottom of the extruder.
With the extruder made, we hooked everything up. We loosened the set screws on the solder tips of four irons and fastened them to the posts. We connected an aquarium pump to the side barbed fitting. We used some wood to shim the irons such that the extruder was level.
With it assembled, we fed solder into the top of the extruder:
For the next version, we have a couple of improvements:
- Using a band saw, we shortened the soldering iron mounting posts to promote faster heating.
- We flipped the extruder upside down so the posts wouldn’t get in the way. To do this, we had to switch the fitting on the bottom and the fitting on the top. This was easier said than done.
- To find the right pressure and pulse frequency for the air, we wanted to find a device that allowed us to vary both. We will try connecting the tube to a speaker. Using software, we can vary the sound frequency and thus the pulse frequency. By increasing the volume, we increase the pressure. Through experimentation, we hope to discover a pulse frequency and pressure that yields the most continuous solder flow.