The best supplier of accurate carbon rods/tubes I can find is in Germany

http://www.shop-en.carbon-composite....st=KAT11-10113

They do high precision Carbon fibre tubes of various wall thicknesses some are centerless ground. I have bought from them in the past. The site is in english and you can use Paypal.

The best ali tubes are again from Germany and are gold anodised in colour. I had some tubes on one of my models bend and when I fitted better quality gold ones I also fitted a tube inside it glued in with PU glue. These have been perfect. If the tubes are small section they can be filled with wooden dowel rod but on a large plane will probably be too heavy.

I cannot find the German supplier of the tubes just now but if I find it I will post later.

John