5.3.1 Static gaps

Static gaps can take several forms. The most basic is just two electrodes spaced a small distance apart. This can be the heads of two heavy bolts or two brass knobs from the hardware store. This is an easy gap to implement and will serve Ok for the beginner. The spacing between the electrodes depends on the power supply voltage from your transformer. 9kv neons do well with about .150 inch of gap while 12kv neons can use up to .200 inch. 15kv neons can use up to .250 inch. Wider gaps than this should be avoided as they put a great deal of stressn your capacitor and transformer. The single static gap while easy to build is a poor performer. All the heat is dissipated in one area and the gap doesnt want to quench. The hot ions in between the gap electrodes tend to keep the gap lit at lower voltages. Blowing air through the gap with a fan or blower will improve the operation of this type of gap by removing these hot ions. A much better approach is to break up the single large gap into a series of smaller gaps in series. This is called a series static gap. This divides the arc up into smaller parts that develop less heat and operate more efficiently. This type of gap also benefits from a little forced air to remove hot ions. One such gap popularized by Richard Quick and often referred to as the RQ cylinder gap consists of multiple electrodes made from lengths of hard copper tubing. The electrodes are usually made from 3/4 or 1 inch copper tubing cut from 2 to 4 inches long. Larger and longer elctrodes provide more thermal mass and handle the heat better. These electrodes are mounted inside a piece of PVC pipe and spaced about .025-.03 inch apart. 7 such electrodes providing 6 gaps between then are normally used for 9kv neons and 9 electrodes providing 8 gaps are used for 12kv neons. Up to 11 electrodes with 10 gaps can be used for 15kv neons. A small muffin fan is mounted on the end of the PVC pipe holding the electrodes to provide cooling airflow.