@Steve Tyler posted:Thanks for the sentiment, Mike, and I'll see your vacuum tubes and raise you a DIY relay! Well, at least the attempt . . .
Not having anything remotely resembling a suitable relay, neither as a discrete part nor in something I'd be willing to sacrifice to the effort, I decided to go full old-school science project and wind my own ( 😜
Well if you really want to build your own flasher, see the attached step-by-step instructions for building thermal time-delay relays. Just arrange one to control itself!