For 1/8A - F BP motor clusters the very best igniters are the Q2g2 from Quest!.
But let me back up for a moment. Before using
any Igniter/Starter/initiator on the market; What is the very most important thing any rocketeer can do when using commerically available ignition product(s). The Answer!
TEST! TEST! TEST! Continuity and/or Ohm test each and every Igniter that is to be used in any cluster
BEFORE it is installed,
AFTER it is installed in the motor and One last time
ON THE PAD while hooking up the micro-clips.
All that said: Over the years I personally have used sucessfully Estes solar igniters (IF ALL are TESTED), and a number of pyrogen tipped Home dipped igniters.
For the last 20 or so years I've made my own using 30ga Nichrome wire & 1Ns APCP dipped igniters for all my cluster rocket applications 2 to 12 motors.
While that example may not be for everyone. There are still a couple very good igniter kits out there (Igniterman and FireStar) Unfortunately I haven't used these kits in a long time but still use the pyrogen every now and then on special projects.
Another thing to keep in mind when flying Multi motor clustered models: A controller with AA or AAA batteries is NOT going to have enough juice to sucessfully igniton clusters over two motors. ANY Cluster with 3 or more motors must use a 12V high amp/hr Battery.
I am a HUGE supporter of the
RELAY Ignition System for Clustered motor rocket ignition. If you are really interested in what has to happen in the first milliseconds after the launch button is pushed please visit
www.narhams.org from the left hand drop-down menu look for the Library section, go to the Tech Tip folder, If you'll download Tech Tip-006 "Clustering BP Motors" You'll find it will give you a complete look at everything you need to know about the three parts of a successful Cluster Ignition Launching. The Relay Ignition System, The Battery Choice, and Igniter Testing & Installation. You'll also see diagrams and parts lists for a couple different Relay ignition systems, Common motor connection methods, and an in depth igniter installation and checking continuity with a pocket easy to build igniter tester.
While noting is ever perfect: I can state that since converting ALL my cluster motor rockets to fly from either a HD 40amp DPDT relay ignition system or a 10amp DPDT Range Box Relay system. I can report over 2000 multi-motor cluster rockets launched (2- 16 motors) with Zero individual motor mis-fires on unlit motors since 1990.
I've said for the last couple decades: "Relay ignition systems are not A Way to successfully launch multi-motor rockets,
IT IS THE ONLY RELIABLE WAY to launch multi-motor model Rockets.
Back to the original question: If you can buy Quest Q2g2 igniters...Buy Them. if not use whatever pyrogen tipped igniters you can find, and TEST.
Hope this helps a bit. Much more info in Tech Tip-006