My coil is up and already runs about 30-40min on different days.
I never get flashovers during this time.
Here are some improvements I figure out during this time.
- You need a carefully Antenna positioning - you get flashover to antenna if it is too close and flashover on the secondary when too far away! Optimal position (for me) is between 7,5 and 8,5 cm
- Only use your coil when the coating is really dry!!! If you put on around 10-15 layers it needs up to three days in the sun. You will get flashover on the secondary when you don't spend this time.
- Separate the primary from the secondary - when you don't recognise a blue corona in a really dark room all is fine. I use a textile insulation tape from Coroplast you find it sometimes in car cable trees.
- To avoid flashover from toroid to secondary/primary build a disc which is slightly larger than the toroid - around 1-2cm I use "vulkanfiber" for this.
Check out my picture and the two videos... more on my Youtube channel or Facebook