10mm Rebar can be bent into circles by hand using simple tools. Watch how its done in this video. These rings are perfect for pillars. More Videos on Ferrocement on this channel. For more on ferrocement techniques, see Peter's book Fantastic Ferrocement: https://smile.amazon.com/Fantastic-Ferrocement-Practical-permanent-Architecture-ebook/dp/B007VQAJES and our site www.fantasticferrocement.com. Peter's arts and crafts, books etc for sale, with lots of pictures: www.peterharris.art. Enjoy, and explore the dream! Please see my Etsy Store WizardsForgeNZ.etsy.com