I will add that very early on when I started I used Ping Pong ball lacquer for igniters. I used a particularly energetic, multi-component, oxidizer/metals pyrogen mixture I made from scratch.
They worked fine but I later bought some "real" NC lacquer and use that with the same pyrogen now. I wanted to be a "real" purist.
Probably PP ball lacquer with the BP pyrogen might not be the best way to go but anyone whose tested with it over time, feel free to correct me. As one has mentioned, the components in ping pong balls have probably changed over the years. I've read early on they were made out of true NC lacquer/plastic WITH an inhibitor added so they don't go "pop" when one hits them with a paddle. I assumed that's what I was working with 17 years ago but the pyrogen I mixed up was particularly energetic. (ie. came on light quickly, flared energetically without popping) That probably overcame any deficiencies with that early PP ball lacquer I made.
One tip (and I've mentioned this before): If one ends up with a batch of igniters that go "pop", meaning some pyrogen blows off the wire, breaks the wire and doesn't come up to heat, I suspect the oxidizer/metals ratio might be incorrect. Nonetheless, the igniter batch can be salvaged nicely with one simple trick. Take the igniter head and bend it to put one to three transverse cracks in the pyrogen depending on how long the pyrogen head is. Yeah, you might lose a little pyrogen but most of the time I can place the cracks and not lose pyrogen. Some of my pyrogen heads are probably longer than need be.
I started doing that and the igniters work great. I unfortunately ended up with a large batch of "poppers" and this trick saved them for use.
What I suspect is happening is there is uneven heating of the nichrome, gas builds up too fast leading to the igniter to "pop" and break the wire resulting in a dud. The cracks allow the uneven gas buildup to escape and the pyrogen doesn't pop off. It has time to catch and burn.
I took a "nearly drained" 12 volt battery and did some testing on the batch and it took longer for the heat flux to build up and the igniters burned nominally without cracking the pyrogen heads. There was no uneven gas buildup over the nichrome. O.K. if one wants to use a partially discharged battery and wait 2 to 3 seconds for the rocket to launch then fine. I think a few transverse "cracks" is an easier way to salvage a batch.
Oh note well: I never had this issue with commercial pyrogen kits at all. The ones I used work fine and I recommend a neophyte purchasing a kit to avoid all this rigamarole I went through. Get a wire wrap tool too. People can argue the need for silver soldering the nichrome to the copper lead wires but I got lazy and just use wire-wrapping alone with decent results. The acid flux needs to be neutralized and soldering is just an un-needed step.
O.k. If one is looking for "instant-on". That's another story that I have to admit I've never mastered. I've been told the magic word is "thermite" but can't really discuss that here because formulas would need to be mentioned which isn't appropriate here. Some of the thermites (the doctored ones) can be very dangerous. Some of the straight 2 component ones have a high heat of activation and are relatively safe. Caveat here: If a two component thermite mix is made with ultra-fine powders they can explode or conflagrate at a very high rate.
Example: I took a high heat of activation 2 component thermite mix that is not ordinarily sensitive to ignition. I mixed up 4 grams.
I placed 1.7 grams of the two component thermite in a small plastic canister that had a 12 volt igniter I use to ground test ejection charges. (No need to waste an ematch for ground testing BP ejection charges for rockets)
Took out my launch panel, stood 20 feet away and the thing went up like an M80. The components were too fine a grind, were apparently mixed well and just burned at a very fast rate and made a large "bang". Particle sizes are extremely important when working with powdered thermite.
Also, if one thinks they can have a cheap explosive here. Think again. I tried 10 more times with the same fine ground components and just observed a high speed burn with no bang. The stuff was too inconsistent to use for motor ignition as the flash didn't have a long enough duration and I presume heat flux to start an APCP motor. Those components were too finely ground to make for instant on or staging thermite ignition.
Some of the doctored thermites can go up with an ematch and need a healthy dose of respect and safety equipment.
Take my advice, if not experienced, buy a kit to make igniters for ground launch igniters. If wanting to do airstarts and staging, become an established friend of someone who does it consistently. I've never attempted either and would have to find somebody who does if I was going to try it.
Kurt