rocket tubes?

I am starting on my first telescope making project, attempting to make a 6 inch f8 closed tube dob from scratch. I have looked around for the best tube option and of course I always see sonotube as the easiest and cheapest solution. I would think that a metal tube like aluminum would be the best, but the cost of the tube itself and having someone custom cut it would be way to much. I found a website that someone used rocket tubes for their telescope. Would phenolic material they use for model rocketry be up for the job? I supposedly waterproof and fairly durable and comes in the right size (7.5 ID and 4 ft long) but nobody ever really recommends it (at least I have not seen anything). Does that mean something is wrong with it? Should I just use sonotube? Also the rocket tube is only 48 inches long, so would thatbe cutting it too close for an 6 f8?

If it is Phenolic it would make a great tube. A few coats of polyurethane inside and out, a little sanding and then a final coat of paint. If you are careful with mirror cell and spider selection and placement, 48" would "just" make it, but you may have to add a "lens hood" at the front to prevent stray light glare and cut down on dewing. That could be made from just about anything.

Walt