The iron trapdoor recipe uses 4 iron ingots, while the copper trapdoor uses 6 copper blocks, each made with 9 ingots, making it considerably more expensive than the iron one.
the door has the same issue, being made of copper blocks rather than ingots.
Comments 2
I don't mean to be rude, but you should check the copper block recipe, it does in fact use 9 ingots. The 2x2 copper ingot recipe is unused, which I double checked before reporting to make sure a copper trapdoor crafted the same as iron wouldn't cause conflicts.
if copper doors/trapdoors can't be switched to use ingots, then perhaps the iron ones should use blocks (I personally hate this idea though)
(I'd also like to mention that getting 2 trapdoors from 6 blocks is an absurdly small return, you lose 5 whole blocks and then some)
This is intentional, as all the copper block variants (such as doors, trapdoors, and grates) are made with their respective block types with different oxidation levels and waxed states. Copper ingots cannot oxidize, so the blocks are required.
(Also, copper blocks are made with 4 copper and not 9 🙂)