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Re: Beginner questions

Original poster: "Gerald  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>


Hi Tyler,

I'm presuming you are using a NST for your power source since this is your first coil. The wire between the NST and the main spark gap doesnt need to be heavy (this is a low current path). I do like to use 12AWG speaker wire cause it has lot of fine wire and is very flexable and the insulation is thick. I dont count on the insulation for HV protection however, I just keep it away from things it could arc to. The high current path is the connection from one side of the cap to the tap turn of the primary, from the other side of the cap to the spark gap, from the other side of the spark gap back to the inner turn of the primary coil. A single use of the same speaker wire will probably be fine until you use a NST farm. I use two 15KV 30ma NST and use both conductors of the speaker wire pair for making connections to the primary. I use brass buss bar to connect the ends of the cap strings together and one end of the cap string to the sparkgap. The high current path does need some attention and the importance of this goes up with the power (and current). It is also important to keep the leads and routing short in the high current path.

I would probably recommend 20 turns of primary so you can tap to what it takes to tune. This will give you good range for tuning. I'm currently tapped at turn 17 using the largest cap that my NST can charge (1.6*Cres for a static gap or 2.8*Cres for a SRSG gap). Once you size Cp to your power source, you can use the largest toroid that will still breakout and having a larger primary inductance range will give you more options here. The larger inductance from a 20 turn primary will also reduce the discharge currents in the primary (if your topload is big enough to allow tuning in this range) and be easier on your caps.

Gerry R.

Original poster: Tyler Pauly <rpggod714@xxxxxxxxx>

  Hello, I'm building my first coil. I have some
questions that only need to be asked once. They are:

1. What do you use to connect the "parts - aka the
capacitor, transformer, primary, etc.? Do you use
house wire (12 gauge)?

2. Do you have any words of wisdom on constructing the
primary? Mine will be 12 turns of .25 copper tubing
held by HDPE cutting board. They start at 6" diam. to
17". I originally planned for 6 supports, but not only
was it incredibly hard to "wind" it, but the glue
holding the plastic to the board support gave out. I
know glue wasn't the best idea, so I'm now routing
ruts into my board to slip the strips of HDPE into.
I'm kind of struggling. There's got to be an easier
way to this. Any ideas?

                         Thanks for the help,
                              Tyler