diff --git a/common/buildcraft/silicon/TileAdvancedCraftingTable.java b/common/buildcraft/silicon/TileAdvancedCraftingTable.java
index 42ea61387f..8fd35a15ca 100644
--- a/common/buildcraft/silicon/TileAdvancedCraftingTable.java
+++ b/common/buildcraft/silicon/TileAdvancedCraftingTable.java
@@ -72,7 +72,6 @@ public ItemStack getStackInSlot(int slot) {
 				if (useRecipeStack || tempStacks == null) {
 					return craftingSlots.getStackInSlot(slot);
 				} else {
-
 					if (bindings[slot] >= 0) {
 						return tempStacks[bindings[slot]];
 					}
@@ -85,14 +84,14 @@ public ItemStack getStackInSlot(int slot) {
 
 		@Override
 		public void setInventorySlotContents(int slot, ItemStack par2ItemStack) {
-			if (tempStacks != null && slot >= 0 && slot < 9) {
+			if (tempStacks != null && slot >= 0 && slot < 9 && bindings[slot] >= 0) {
 				tempStacks[bindings[slot]] = par2ItemStack;
 			}
 		}
 
 		@Override
 		public ItemStack decrStackSize(int slot, int amount) {
-			if (tempStacks != null && slot >= 0 && slot < 9) {
+			if (tempStacks != null && slot >= 0 && slot < 9 && bindings[slot] >= 0) {
 				if (tempStacks[bindings[slot]].stackSize <= amount) {
 					ItemStack result = tempStacks[bindings[slot]];
 					tempStacks[bindings[slot]] = null;