Minecraft wiki entry for Scaffolding, associated text: Therefore, when combined with string into scaffolding, a certain amount of bamboo (each smelting 0.25 items) can smelt 8 times‌[until JE 1.19] or 24 times‌[BE only] as many items. When it comes to string costs, each string enables the smelting of 12 items‌[until JE 1.19] or 36 items‌[BE only].