Here are some details on the parts for those interested in building piezo igniters
– The piezo unit is from a common, cheap, one-use lighter. I haven't found any significant differences between units from different devices (the one from a more expensive household gas stove igniter looked the same). Connecting the wire that goes from it to the cable is a bit tricky when there is limited space in the housing as in this case – the connection has to be insulated well to prevent having the spark here – you can see in the third photo how I used some thin PE tube.
– I use teflon-insulated cables mainly to make sure they won't melt accidentally. Additionally, they have better insulating properties and more mechanical strength. Any common (vinyl-insulated) cable can be used but it might be less reliable.
– I guess the most difficult part to source is the insulator that holds the rod going to the burner. The rod might get hot, so it should be heat-resistant. It should have good insulating properties. Teflon is a perfect choice here, it is also water repellent so it should keep it's insulating properties even in wet environment. Polyimide (kapton) would be also fine. You can experiment with other heat-resistant plastic, some resin-based material would be the easiest to find.
– The sparking rod is a piece of a thin stainless steel welding wire. Titanium would be nicer… Anyway, it should be a metal with low thermal conductivity (these two are) as the tip gets red-hot.
– In the teflon insulator, there are three holes drilled vertically – two parallel, the third one in an angle so that it meets with the second one. Here is a figure:
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The U-shaped end of the sparking rod is pressed into the first two holes, the cable goes through the third one and meets the rod insides the block.
