What is the best method to make large diameter tubes?  Diameters will range from 8in to 24 in.  The outside is the finished side.  This will be a large on-going product run, so I don't mind investing in equipment, but can't afford a large autoclave, but possibly could get an oven that size.  So that leaves me with OOA prepreg and Vac infusion.




I personally think that the easiest way will be to get cylindrical Acrylic tubes made in the desired inner diameter and build on the outside and vac infuse.  The issue with this is that I'll have to take the time to sand and clear the outside to get the desired finish. 

The second option is to do the same thing, but build on the inside of the form.  I don't see a problem doing it this way on the larger diameter tubes since its not to hard to get a vacuum bag on the inside, but the smaller ones might be an issue.  I've heard of using bladders to inflate on the inside, but have never seen it in action.

The problem with using prepreg in an oven is that I don't know what kind of temps the acrylic forms can sustain without failing.

What are the other options? 

Hahaha,

Your not Alan Gilby by any chance? if so you've built drums for me!

Are you building purely in carbon,

how do you intend to do the skin seat (forgot the word) you could work clever and have this as finished in the lay-up.

No, I ran a small custom durm shop in Florida.  I build with all materials.  There is only one company that makes carbon shells called Rocket Drums.  Beautiful work but expensive.  As far as the bearing edges, hopefully I'll be able to take care of all of that during layup.  I've got the ideas, now I just need to engineer it correctly......