Years ago I fell in love with the pretty rustic pictures showing bundles wrapped on pieces of wood. In reality wooden dowels tend to be heavier, do not heat from the inside out and waste energy as they themselves heat, are often not perfectly straight, and I kept the pieces of garden posts but no longer use them!
I very much prefer hollow metal pipes. My favourite one is a piece of a motorbike fork cut to fit in my steamer, I also rescued 4 stainless steel legs from an old coffee table with an even larger diameter.
Metal is a very good heat conductor so they heat evenly. Because they are hollow, they heat the inside of the bundle too, faster. I couldn’t do without them now! What do you prefer to use?
An exception to the metal pipe rule is my plastic indigo dip-dye pipe, for lower temperatures, which I believe was a downpipe in its previous life 🙂