Tinker I/O adds an item called “Solid Fuel”. Put the Fuel Input Machine next to close to the Smeltery Controller, and you can use this machine to put the Solid Fuel into the Smeltery Controller. As long as you collocate with “Speed Upgrade”, you can transform metals into the form of liquid immediately.

Download Tinker I/O Mod 1.7.10, 1.7.2