Issue description:
As the title states, when extracting from the seared furnace, currently smelting items will still flow out to whereever an output source is, such as a hopper or item translocator

Versions:

• Minecraft: 1.12.2
• FTB Revelation: 3.4.0
• Forge: 14.23.5.2846
• Mantle: 1.3.3.55
• Tinkers Construct: 2.12.0.157

Can it be reproduced with just Tinkers Construct? If not, list the other mods required to reproduce the issue.

If this was an actual bug, that last question would have been important. Don't skip answering questions in the template.

However, this is intentional design for the block. We decided to leave the furnace dumb as a bit more of a challenge to automate as the primary design is a convenience for non-automated furnaces. The design may get reworked for 1.16 but for 1.12 its being left as non-trivial to automate. If you want something easy to automate, use a vanilla furnace.