Filament wound tubing, like Hawk Mountain, Dynacom and Giant Leap is not as strong axially as convolute wound tubing like Performance Rocketry makes. That is not to say it isn't strong enough, but that depends on the tubing, the motor, etc. etc. Personally I prefer convolute wound tubing.

You cannot push either of them hard enough to make them fail (convolute or filament). Convolute is waaaaay easier to drill and sand. That was my story when I was a dealer and I'm sticking with it...

Thanks Warren and John for the reply. I think most of us take for granted how valuable these forums are to this hobby. Appreciate it and I am sure I will have more questions building this project.

John, I want to qualify my "you can't push the tubing hard enough to make it fail" comment.... If you have a very tall rocket or a 2-stage that has a bad interstage coupler, all bets are off. That said, many of us have put astounding strain on glass airframes and they are generally fine... I've flown N's in minimum diameter glass, no problem.

Several of us have also put J570s in 38mm rockets that weighed about 1 lb. and they were just fine. If that same rocket was 6 feet tall with a bunch of joints - then that is a different deal...

John, I am looking at a rocket about 13 feet with a joint in booster for parachute deployment and the sustainer a dual deploy. Sims about 22,000 feet. I would use G-10 couplings and shear pins.

Backing up John on this, both of us flew very similar birds of about 32" in length with J570s and dual deploy within 15 minutes of one another. Not a problem... both filament wound Hawk Mtn type tubing and couplers.

Given what you're doing, go with convolute wound tubing if you're going minimum diameter.

This is not a minimum diameter project Warren. For the materials Performance Rocketry is about $100 more with some "waste" due to the tubing available only in 48" lengths. Hawk Mtn. has more variety of lengths.