Rolling a length of putty between your fingers gives an uneven, tapered worm every time. A roll maker is two flat plates that do it properly: put a small ball of putty between them, move the top plate, and you get a rod of constant diameter as long as the plate allows. Change the pressure and you change the thickness, which means cables, hoses, straps, bedroll ties and trim all come out matching instead of approximate.
Work with a slightly damp surface so the rod releases, and roll just before you need it — a thin strand cures much faster than a lump. Soft, stretchy grades from epoxy putty roll best; stiff, fine-grained types tend to crack along the length. Once the strand is laid on the model, steel sculpting tools are what you use to press it into place and cut it cleanly. The rest of the branch is in sculpting tools and materials.
