Need a simple timer for gas fired dragon display

[cts2013]

Good afternoon.
I am a gas engineer and built 2 x fire breathing dragons for a display.
Simple regulated gas supply to the nozzle (running through a 12volt supply solenoid) - ignited by a electronic switch that sparks the ignite.
The switch is a simple bridge connector and she sparks.

I need run this through a timer - I can use a simple electronic timer to say turn on the gas solenoid supply every hour on the hour for say 15 minutes...
but I don't want the igniter to be on for the 15 minutes - only need this to flash for say 5 to 15 seconds.

I though of doubling up the same timer - but the only domestic ones I can find have a minimum on time of 1 minute.
Any suggestions appreciated. I'm handy with a soldering iron so happy to build a small circuit if this would dot he job.

Thanks again,
Peter