Describe the bug
Make sure to include:

1. What did you expect to happen?

I expected the metal unit amount to decrease as the armor took durability hits

2. What actually happened instead (i.e. what was the bug)

the armor keeps the metal unit amount equal to the base creation cost, and it never changes

3. If it was a crash, upload the full log file (latest.log)

no crash

4. If they would help to explain the issue, include screenshots

Freshly crafted, undamaged helmet

Almost entirely used, destroyed helmet

results in 600 units of original metal

To Reproduce

1. Craft a piece of metal armor.
2. Check the melt value.
3. The value should be equal to the amount of units put in (it is).
4. Damage the armor by repeatedly taking damage while wearing it.
5. Check the melt value.
6. The value should be less than the amount of units put in (it's not).

Meta Info

• TFC Version: 0.23.8.75
• Were any other mods included? Can you reproduce it without these other mods?
  JEI, JMap, WAILA
• If necessary, what other mods (including versions) MUST be present to experience the bug?
  did not test