Add a hook for the default color and use it for arrow fletchlings and bowstrings

src/main/java/tconstruct/items/tools/Arrow.java

@@ -8,7 +8,10 @@ import net.minecraft.item.*;
 import net.minecraft.nbt.NBTTagCompound;
 import net.minecraft.util.StatCollector;
 import net.minecraft.world.World;
+import tconstruct.library.TConstructRegistry;
 import tconstruct.library.crafting.ToolBuilder;
+import tconstruct.library.tools.BowstringMaterial;
+import tconstruct.library.tools.FletchingMaterial;
 import tconstruct.library.tools.ToolCore;
 import tconstruct.tools.TinkerTools;
 
@@ -41,6 +44,15 @@ public class Arrow extends ToolCore
         }
     }
 
+    @Override
+    protected int getDefaultColor(int renderPass, int materialID) {
+        // fletchling uses custom material
+        if(renderPass == 2)
+            return TConstructRegistry.getCustomMaterial(materialID, FletchingMaterial.class).color;
+
+        return super.getDefaultColor(renderPass, materialID);
+    }
+
     @Override
     public String getEffectSuffix ()
     {