Items obtained from market as payment for goods sold seem to glitch out a bunch. My solution is to:
1. Obtain iron you can craft with.
2. Get the iron you can't craft with.
3. Get a crafting bench.
4. Open the crafting bench, with less than a stack of iron you can craft with in your inventory.
5. Put the iron you can't craft with into the crafting table, then shift click it back out. It should join with the iron you can craft with.
6. You can craft with the iron now.